Super APES Prep

Chapter 0 - Introduction

Intro to Notes

• These notes are based on the “Exploring Environmental Science for AP, AP Enhanced Edition, 1st Edition.” You can find this textbook here.

AP Testing Tips

• BE VERY SPECIFIC! Especially about trends: say if the trend is rapidly increasing or slowly decreasing, and etc.

• BE VERY CONCISE! Only specify one of each thing: less forests == less ways to sequester CO2 == more CO2 in the atmosphere, causing climate change. That’s it.

Chapter 1 - Science, Matter, Energy, and Systems

1.1 - What do Scientists Do?

• Use Observations, measurements, and experimentation to understand science’s cause-and-effect patterns.

• Be skeptical about everything you read/hear

• Evaluate evidence/hypotheses with many reliable sources

• Take your personal assumptions/biases/beliefs into account, distinguishing between facts and opinion, before you come to a conclusion.

• Scientists can’t prove something absolutely due to degrees of uncertainty in measurements or hypotheses/theories. So, scientists use Probability: the certainty of a scientific theory of being useful for understanding some aspect of nature

• Scientists are Human, and may have bias. This is greatly reduced by the high standards for evidence and peer review.

• Many natural systems have many, many variables with complex interactions, making it too difficult, costly, and time consuming to test one variable at a time. Mathematical models are used to take into account multiple variables interacting.

• Statistical sampling and mathematical methods must be used because there’s no way to measure completely accurately.

1.2 - What is Matter and What Happens When it Undergoes Change?

• Physical Forms: solid, liquid, gas

• Chemical Forms: elements, compounds (2+ elements held together in fixed proportions)

• Atoms (smallest unit of matter in which an element can still have its chemical properties), which are themselves made up of 3 subatomic particles (proton/neutron/electron)

• Molecules (2+ atoms of the same/different elements)

• Ions (group of atoms with a net positive or negative charge):
• Use pH to measure acidity (comparative amounts of hydrogen H+ and hydroxide OH- ions)

• Has an Atomic Number (# of Protons) and an Atomic Mass (protons + neutrons)

• Isotopes: # of Protons ≠ # of Neutrons

• Hydrocarbons are compounds of carbon and hydrogen (wow, how crazy)

• Complex Carbohydrates have 2+ monomers of simple sugars (contain carbon, hydrogen, and oxygen atoms). Ex: Starch, cellulose

• Proteins (made of amino acids) and Nucleic Acids (made up of nucleotides) and Lipids (do not dissolve in water)

• Genes compose DNA Molecules, which contain genetic info (traits) that are passed on through reproduction. Genes compose chromosomes.

• Physical: No change in chemical compositions (ex: Aluminum foil cut into pieces, ice to water)

• Chemical: Chemical composition of the substances involved changes (ex: combustion reaction)

• Law of Conservation of Matter: Whenever matter undergoes any kind of change, no atoms are created or destroyed. Unless I’m involved.
• To abide by this law, you have to balance chemical equations.

1.3 - What is Energy and What Happens When it Undergoes Change?

• Moving Energy (Kinetic Energy - matter in motion)
• Electromagnetic Radiation: Form of Kinetic energy, where energy travels from one place to another through waves of varying wavelengths
• Heat/Thermal Energy: Form of Kinetic Energy, represents the total kinetic energy of all moving matter in an object.
• Radiation: Transfer of heat energy by electromagnetic radiation using infrared radiation
• Conduction: Transfer of heat from one solid substance to a cooler one through physical contact
• Convection: Transfer of energy through warmer liquids/gases rising to cooler liquids/gases, and vice versa.

• Stored Energy (Potential energy)
• Nuclear Energy: stored through the chemical bonds that hold particles together in the nuclei of atoms.

• Electric Power: Measured in watts, it is the rate at which electric energy is transferred through a wire or other material.

• 90% of the Commercial energy (energy sold in the marketplace) comes from burning fossil fuels.

• High Quality: concentrated energy with a high capacity to do useful work (high temp heat, concentrated sunlight, high-speed wind, burning fossil fuels)

• Low Quality: Little capacity to do useful work due to its dispersion (moving molecules in the atmosphere/ocean)

• High Quality: is concentrated/organized/can be combusted to release energy (wood, coal)

• Low Quality: Can’t do work with it (ashes - can’t be burnt again)

1. Conservation of Energy (Whenever energy is converted from one form to another in any type of change, no energy is lost.)

2. Entropy: Whenever energy is converted from one form to another, we end up with lower-quality or less-usable energy, usually taking the form of heat dispersing into the environment (AKA energy always goes from a more useful to a less useful form when changing from one form to another)

1.4 - What are Systems and How do they Respond to Change?

• Inputs of matter, energy, and info from the environment

• Flows/Throughputs of matter, energy, info within the system

• Outputs of matter, energy, and information to the environment.

• Positive Feedback Loop: causes a system to change further in the same direction

• Negative/Corrective Feedback Loop: changes a system in the opposite direction.

Chapter 2 - Ecosystems: What Are They and How Do They Work?

2.1 - How does the Earth’s Life-Support System Work?

• Atmosphere: Spherical mass of air, composed of the troposphere (innermost layer, contains the air we breathe), stratosphere (second layer, contains enough ozone to filter 95% of UV light)

• Hydrosphere: All the water on/near the earth’s surface (water vapor in atmosphere, liquid water on the surface, etc).

• Geosphere: Includes the earth’s rocks, minerals, and soil.

• Biosphere: Parts of the atmosphere, hydrosphere, and geosphere where life is found.

• One-way flow of high-quality solar energy (supports plant growth, providing energy for plants and animals. Also interacts with gases in the troposphere to warm it greenhouse effect - which keeps Earth from being too cold).

• Cycling/Recycling nutrients (chemicals necessary for an organism’s survival) through parts of the biosphere, since the Earth doesn’t get significant matter inputs from space.

• Gravity!! It holds the atmosphere and allows for the cycling of matter and chemicals through everything!

2.2 - What Are the Major Components of an Ecosystem?

• Biosphere and its ecosystems have living (biotic) and nonliving (abiotic) components

• Each organism in an ecosystem is assigned a feeding level (trophic level) based on where it gets its food/nutrients from. Organisms are also classified as either producers (autotrophs - make the nutrients they need from the elements in their environment - photosynthesis, for example) or consumers (heterotrophs - cannot produce the nutrients they need, and must gain them from feeding on other organisms/their waste and remains).
• Producer Examples: Trees and green plants, algae, aquatic plants, phytoplankton, cyanobacteria
• Consumer Types: Primary Consumers (herbivores, only consume producers), Secondary Consumers (feed on herbivores), Tertiary Consumers (feed on herbivores and other carnivores)
• Decomposers: Consumers that eat the wastes/remains of plants and animals (bacteria or fungi)
• Detritus Feeders/Detritivores: feed on the wastes or dead bodies of other organisms (earthworms, soil insects, hyenas, vultures)

• Slow renewable resource (becomes nonrenewable if we deplete it too fast - takes thousands of years for 1 inch of topsoil). Protecting and renewing this topsoil is a key to sustainability.

• Ex: Sea otters eat urchins, who eat kelp, the producer of this ecosystem. If sea otters disappeared, the urchin population would significantly increase, resulting in increased kelp consumption and a degradation of the kelp in the ecosystem. This would dissipate many of the populations that reside in and rely on the kelp.

2.3 - What Happens to Energy in an Ecosystem?

• Each transfer of energy from one level to the next involves a loss of some high-quality energy to the environment in the form of heat

• Only 10% of energy is transferred to the next trophic level (90% of the energy of the organism is lost as heat, usually when trying to kill the organism)
• Thus, Vegetarian diets (or lower trophic level diets) are more energy efficient than Carnivorous/ Higher trophic level diets, because there’s more energy in the lower levels.

• Both webs and chains show how producers/consumers/decomposers are connected to each other as energy flows through the trophic levels

• Measures how fast producers can make the chemical energy that is stored in their tissues + is potentially available to other organisms in an ecosystem.

• Ex of NPP vs. GPP: GPP would be your net salary, and NPP would be the money you have left after subtracting the necessities (transport, clothes, food, etc)

• Places with a large number and variety of producers have high NPPs. NPP itself represents the available nutrients for consumers - the planet’s NPP limits the number of consumers that can survive on the Earth.

• Ex: Many hectares of grass are required to support a single hawk, because when high-quality chemical energy from the lower trophic levels is transferred to another trophic level, 90% of it is lost, degraded to low-quality energy (heat) that dissipates into the environment, as per the second law of thermodynamics.

2.4 - How Do Species Interact?

• In total, competition reduces population size since there are fewer resources available.

• Temporal Partitioning: Using resource at different times

• Spatial Partitioning: using different areas of a shared resource

• Morphological Partitioning: using different resources based on different evolved body features

• Predation: one species acts as a predator, feeding directly on another species (prey). At its core, the predator benefits (it has food), and the prey is harmed (decreased population).

• Many predators use a variety of ways to help them capture prey, from speed, flight, good eyesight, working in groups, poison, or camouflaging.

• Meanwhile, prey species have evolved ways to avoid predators, through running, swimming, speed, highly developed senses of sight/sound/smell, protective shells, thick bark, spines and thorns, chemical warfare, mimicry, bad taste, foul smells, and camouflage.

• This species interaction has a strong effect on population sizes and ecosystems (ex: sea otters help to protect kelp forests by eating sea urchins).

• Edward O. Wilson’s criteria for the dangers of bright-colored animals: small and beautiful = poisonous, beautiful and easy to catch = deadly.

• Coevolution: a natural selection process where changes in the gene pool of one species leads to changes in the gene pool of another species - predators hunt the less fit prey, and as the prey evolve, only the fittest predators are able to survive, serving as an example of natural selection.

• Helps the predator and prey species become more competitive or to avoid/reduce competition

• Parasitism: A parasite species lives in or on another host species. The parasite benefits by extracting the host’s nutrients, and as a result, the host is harmed. The host isn’t killed, though, but weakened (why would you kill your source of nutrients)

• Ex: Tapeworms, mistletoe plants, fleas and ticks

• Mutualism: Both interacting species benefit by providing each other food, shelter, or some other combination of resources.

• Ex: Pollination of plants by bees (bees get nectar, plants get to spread their genes)

• While it appears to be cooperation between species, both species are only concerned for their survival.

• Commensalism: Benefitting one species but having little beneficial/harmful effect on the other

• ex: when a pitcher plant or bird nests itself in a tree, benefitting from the shelter while the tree gets no effect.

2.5 - What Happens to Matter in an Ecosystem?

• Powered by the Sun, whose solar energy causes evaporation (turning some of the liquid water in oceans/lakes/rivers/soil/plants to vapor, which thenrises in the atmosphere).

• Through precipitation (which mostly becomes surface runoff - water flowing off the land into bodies of surface water), water can flow into bodies of water to repeat the cycle, or be absorbed into the porous underground layers of soil, rock, sand, and gravel (aquifers), becoming groundwater (water that’s stored underground, in aquifers)

• Only 0.024% of the Earth’s water supply is available for organisms in the form of freshwater.

• How Humans Affect the Cycle:
• withdrawing water from rivers/lakes/aquifers at a faster rate than nature can replenish them
• clearing vegetation from land for agriculture, mining, road building, and other construction activities + covering much land with buildings, concrete, and asphalt -> increased water runoff, reduced infiltration into the ground (as a result, less groundwater)
• Draining and filling wetlands (act like sponges to absorb and hold overflows of water from drenching rains or melting snow) for farming and urban development

• CO2 makes up 0.04% of the troposphere, and, along with water vapor, affects the temperature of the atmosphere (greenhouse effect) -> even slight changes in this cycle can affect the climate, which can determine the types of life that can exist in some places

• Cycled through the biosphere through photosynthesis (which sequesters CO2 from the air/water) and aerobic respiration by producers/consumers/decomposers (which adds CO2 to the atmosphere). Some CO2 dissolves in the ocean while decomposers in the ocean also release carbon. Marine sediments are the largest deposits of carbon.

• How Humans Affect the Cycle:
• By using and burning fossil fuels, we’ve been adding CO2 to the atmosphere faster than the carbon cycle can remove it. As a result, CO2 levels have been rising since 1960.
• As a result, we warm the atmosphere and change the earth’s climate
• Clearing carbon-absorbing vegetation from forests (ex: cutting down trees in tropical forests) faster than they can grow back reduces the ability of the carbon cycle to remove excess CO2.

• Plants can use nitrogen in the form of NH3, NH4+, and NO3- (Ammonia, ammonium ions, and nitrate ions). These forms are created through lightning + specialized bacteria in topsoil (N2 to NH3- Bacterial Fixation). Other bacteria in topsoil + bottom sediments of aquatic systems convert NH3 to NH4+ and NO3-, which are then taken up by the roots of plants. The plants create various proteins/nucleic acids/vitamins that animals eat.

• Bacteria in waterlogged soil and bottom sediments of lakes/oceans/swamps/bogs convert nitrogen compounds into N2, (Denitrification) which is then released into the atmosphere again.

• Nitrogen Sink vs. Source: reservoir that takes nitrogen vs. releases nitrogen into the atmosphere

• How Humans Affect the Cycle:
• The high temps that result from burning fossil fuels convert some N2 and O2 in the air to NO (nitric oxide - Synthetic Fixation), which can then be converted to NO2 and HNO3 (Nitrogen dioxide and nitric acid vapor), which can return to the earth’s surface, causing acid deposition (acid rain). This damages buildings, statues, and forests.
• We remove large N2 from the atmosphere to create ammonia and ammonium ions for fertilizers + add nitrous oxide (N2O) to the atmosphere through the anaerobic bacteria in nitrogen-containing fertilizer or organic animal manure added to the soil, which warms the atmosphere and helps to deplete stratospheric ozone. Ozone blocks the sun’s UV rays, so this is extra super bad.
• By adding excess nitrates (NO3-) to aquatic ecosystems through agricultural runoff of fertilizers (excess fertilizer -> Ammonia Volatilization), animal manure, and discharges from sewage treatment systems (Leaching), this contaminates bodies of water, resulting in excessive algae growth which disrupts aquatic systems. (Eutrophication)

• Water running over exposed rocks slowly erodes inorganic compounds containing phosphate ions, which are then carried into the soil, absorbed by the roots of plants/other producers, and are then transferred by food webs from producers -> consumers -> detritus feeders and decomposers
• Weathering is so slow that Phosphorus is often a limiting nutrient in aquatic and terrestrial ecosystems

• Phosphate and phosphorus compounds that wash into the ocean are deposited as marine sediment and can remain trapped for millions of years (sedimentation - P sediments can be compressed into sedimentary rock by water pressure) until geological processes uplift and expose these seafloor deposits, which can then be eroded and freed up to expose the phosphate deposits and re-enter the phosphorus cycle.

• Geological Uplift: Tectonic plate collision forces up rock layers that form mountains - this restarts the P cycle with weathering and release of phosphates from rocks.

• As soil contains little phosphate, this limits plant growth on land (limiting nutrient) until phosphorus in the form of phosphate salts being mined from the earth are added to the soil as fertilizer. Lack of phosphorus also limits the growth of producer populations in freshwater streams/lakes, because phosphate salts are only slightly soluble in water and do not release many phosphate ions to producers in aquatic systems.

• Human Activities that Affect the Cycle:
• Removing large amounts of phosphate from the earth to make fertilizers
• Clearing tropical forests, reducing phosphate levels in tropical soils
• Phosphate ions being carried into streams/lakes/oceans due to eroded topsoil and fertilizer washed from fertilized crop fields/lawns/golf courses stimulate the growth of producers (ex: algae and other aquatic plants), which upsets chemical cycling and other processes in bodies of water.
• Our inputs of phosphorus into the environment (mostly bc fertilizers) have exceeded the planet’s environmental limit for phosphorus. Wait, how does that work???

• Algae Bloom covers surface of water blocking sunlight and killing plants below surface

• Algae eventually dies off, bacteria that breaks down dead algae uses up O2 in water (decomposition is an aerobic process)

• Lower O2 levels in water kills aquatic animals, especially fish

• Bacteria use up even more O2 to decompose dead aquatic animals in addition to algae

• This is a Positive Feedback Loop (Less O2 -> more dead organisms -> bacteria use O2 to decompose them -> Less O2)

• Disruption of the nitrogen and phosphorus cycles, mostly from greatly increased use of fertilizers to produce food

• Biodiversity loss from replacing biologically diverse forests and grasslands with simplified fields of single crops

• Land system change from agriculture and urban development

• Climate change from disrupting the carbon cycle, mostly by overloading the atmosphere with carbon dioxide produced by the burning of fossil fuels

2.6 - How Do Scientists Study Ecosystems?

• Using field research (going into forests/oceans/other natural settings to study the structure of ecosystems), laboratory research, and mathematical models to learn about ecosystems

• To study tropical forests, some scientists build tall cranes to read the canopies, climb trees, or install rope walkways, helping to identify and observe the diversity of species living in these habitats.

• Scientists also use aircraft/satellites with remote sensing devices to scan/collect data on Earth’s surface. They use Geographic Information System software to capture/store/analyze/display this information (ex: converting digital satellite images into global, regional, and local maps)

• Some attach tiny radio transmitters to animals and use GPS to track where/how far they go. This helps when studying endangered species. Scientists also use cell phone cameras, time-lapse cameras, and cameras on drones/stationary objects.

• Ecologists conduct laboratory research (creating, setting up, and observing simplified models of ecosystems and populations in containers like culture tubes, bottles, greenhouses, indoor/outdoor chambers, etc. while controlling for temperature, light, CO2, humidity, and other variables)
• Make it easier to carry out controlled experiments (less costly and faster than similar experiments in the field)
• Scientists, however, must reflect on how well their experiments reflect what takes place under the real conditions found in nature, which tend to be more complex and ever-changing.

• Ecologists call for greatly increased research on the condition of the world’s ecosystems to see how they’re changing, which will help them develop strategies to prevent and/or slow down their degradation + will help us avoid going beyond ecological tipping points.

• Life is sustained by the flow of energy from the sun through the biosphere, the cycling of nutrients within the biosphere, and gravity.

• Some organisms produce the nutrients they need, while others survive by consuming other organisms/ consuming the wastes and remains of other organisms while recycling nutrients to be used again by producers. This cycle continues on and is essential to life.

• Human activities are altering the flow of energy through food chains and food webs and the cycling of nutrients within ecosystems and the biosphere.

Chapter 3 - Terrestrial Biomes

3.1 - How Does Climate Affect the Nature and Location of Biomes?

• Different climates based on long-term average annual precipitation and temperatures, global air circulation patterns, and ocean currents, lead to the formation of tropical (hot), temperate (moderate), and polar (cold) deserts, grasslands, and forests.

• Avg. Precipitation and Temperature act as limiting factors over time, helping to determine the type of desert/grassland/forest in any particular area, and thus, the types of plants -> animals and decomposers found there, too.

• Biomes consist of a variety of areas with somewhat different biological communities but with similarities typical of the biome, thanks to irregular distribution of the resources required by plants and animals, and human activities altering the landscape and vegetation in these areas.

• Tropical Deserts: are hot and dry most of the year, with few plants and a hard, windblown surface strewn with rocks/sand.

• Temperate Deserts: have high summertime and low wintertime temperatures in the day, with more precipitation than in tropical deserts. They have sparse vegetation consisting of mostly dispersed, doubt-resistant shrubs, cacti, or other succulents adapted to the dry conditions and varying temperature.

• Cold Deserts: vegetation is sparse, winters are cold, summers are warm or hot, and precipitation is low.

• In All Deserts, plants and animals have evolved adaptations helping them stay cool and get enough water to survive (ex: dropping their leaves during hot spells to avoid transpiration, opening pores only at night to release CO2, spines to protect them from herbivores trying to steal their water)

• These desert ecosystems are vulnerable to disruption because:
• Slow plant growth
• Low species diversity
• Slow nutrient cycling
• Low bacterial activity in their soils
• Very little water
• It can take decades to centuries for their soils to recover from the smallest disturbances (ex: off-road vehicles), which can also destroy the habitats for a variety of animal species. Plus, the lack of vegetation in tropical/polar deserts make them vulnerable to heavy wind erosion from sandstorms.

• Tropical Grasslands (Savannas, for example): have widely scattered clumps of trees, warm temperatures year-round with alternating dry/wet seasons. They have herds of grazing/browsing animals migrating across to find water in food in response to seasonal/year-to-year variations in rainfall + food availability. The savanna plants are adapted to survive drought and extreme heat, with deep roots that use groundwater!
• Let’s talk about the African Savanna and its keystone species, the Elephant.
• Eating woody shrubs and young trees, they prevent the savanna from being overgrown and prevent the grasses, the foundation of the food web, from dying out. They also dig for water during droughts, creating or enlarging waterholes used by other animals.
• If they left, antelopes, zebras, and other grass-eaters would make the grass extinct and then leave the savanna in search of more food, and the carnivores would follow them. Thus the ecosystem would be left empty

• Temperate Grasslands (short-grass and more-precipitation-receiving tallgrass prairies): have bitterly cold winters, hot and dry summers, and sparse, uneven annual precipitation. They have deep, fertile topsoil, mostly because of the accumulation of dead grasses every year, which is held in place by a thick network of the grasses’ intertwined roots. These grasses are adapted to droughts and to fires that burn the plant parts above the ground but not the roots. Winds blow continuously and evaporation is rapid, leading to fires in the summer/fall.

• Cold Grasslands (arctic tundra): are treeless, bitterly cold, swept by frigid winds, and covered with ice and snow. They have long winters with few hours of daylight, and the little precipitation falls as snow. Under the snow lies a thick mat of low-growing plants (grasses, mosses, lichens, dwarf shrubs) as trees and other tall vegetation can’t survive in the cold, windy tundra. The plants in this tundra only really grow during the short 7-8 week summer, where daylight is continuous.
• This extreme cold causes the formation of permafrost (underground soil where captured water stays frozen for 2+ years). This keeps melted snow and ice from draining into the ground, and results in the formation of shallow lakes, marshes, bogs, ponds, and other seasonal wetlands after snow and frozen surface soil melt, attracting many insects for migratory birds.
• To survive this intense cold, animals have thick coats of fur/feathers or live underground.
• The tundra is vulnerable to disruption - the short growing season (the summer) means tundra soil and vegetation recover very slowly from damage, so human activities (oil/natural gas drilling sites, pipelines, mines, military bases) leave persistent scars.
• Alpine Tundras: occurs above the limit of tree growth but below the permanent slow line on high mountains. They have similar vegetation to that found in an arctic tundra, but it receives more sunlight, resulting in an array of beautiful wildflowers in the summer.

• Has mostly dense growths of low-growing evergreen shrubs, occasional small trees with leathery leaves. Animals include mule deer, chipmunks, lizards, and more. Has thin, not very fertile soil. During the long, hot, and dry summers, this vegetation dries out and in the late summer/early fall, fires start and spread fast.

• Chaparral is adapted to/maintained by these fires, as many of the shrubs store food reserves in their fire-resistant roots and have seeds that sprout only after a hot fire. After the first rain, grasses and wildflowers spring up, using the nutrients released by the fire. New shrubs grow quickly and the grasses are crowded out.

• Thanks to its moderate, sunny climate, humans love inhabiting this area, and as a result, there’s little natural chaparral left. But there’s the danger of frequent fires and mudslides brought by heavy rains.

• Tropical Rain Forests: found near the equator, where hot and moist air rises and dumps its moisture. Lush forests with year-round warm temperatures with high humidity and almost daily heavy rainfall, ideal for many plants and animals. They’re dominated by broadleaf evergreen plants which keep most of their leaves year-round. The relatively few plants at ground level have huge leaves to capture what little sunlight there is, as the tops of the trees form a dense canopy, blocking light from reaching the ocean floor.
• High net primary productivity - tons of biological diversity. Despite covering 2% of Earth, they’re home to 50% of the known terrestrial plant/animal species, with a single tree able to support several thousand different insect species. Plants from these regions contain many chemicals, essential for creating the world’s prescription drugs.
• The species here have a variety of specialized niches in distinct layers, contributing to their high species diversity. Vegetation layers are structured according to the plants need for sunlight, and much of the animal life lives in the sunny canopy later (abundant shelter, supplies of leaves/flowers/fruits)
• Dead plant/animal matter decomposes quickly because of the warm, moist conditions and the hordes of decomposers, with 90% of these decomposed nutrients being quickly taken up and stored by trees, vines, and other plants. The remaining nutrients are leached from the thin topsoil by the frequent rainfall and little plant litter builds up on the ground. This lack of fertile soil explains why rain forests aren’t good to clear up and build grazing lands on.
• Human activities (farming, for example) have destroyed at least half of the world’s tropical forests, and this pace is increasing. Without strong protective measures, most of these forests could be gone by the end of the century, taking their biodiversity along with them.

• Temperate Forests (Temperate deciduous - most common): have warm summers, cold winters, abundant precipitation in the summer and snow in the winter. They’re dominated by a few broadleaf deciduous tree species (oak, hickory, maple, aspen, birch), predators (wolves, foxes, wildcats) that feed on herbivores (white-tailed deer, squirrels, rabbits), and birds that live here during the spring and summer.
• Most of the leaves on the trees fall off, helping it survive the cold winters. Each spring, the leaves sprout again, and the trees spend their summers growing and producing until winter.
• With cooler temperatures and fewer decomposers, these forests have a slower rate of decomposition, allowing them to accumulate a thick layer of slowly decaying leaf litter, becoming a storehouse of soil nutrients.
• These forests have been degraded by many human activities (logging, urban expansion), more than ANY TERRESTRIAL BIOME.
• The Temperate Rain Forests are found in scattered coastal temperate areas, with ample rainfall and moisture from dense ocean fogs. These forests have thick strands of coniferous (large cone-bearing) trees that keep most of their (needles) leaves year-round. These can survive the intense cold and drought of winter.
• The ocean keeps winters mild and summers cool, and the trees in these moist forests depend on frequent rains and moisture from summer fogs. Most of the trees are evergreen because there’s a ton of water. And yes, little light reaches the forest floor.

• Cold (northern coniferous forests - boreal forests - taigas): Found south of arctic tundra, they have subarctic, cold, and moist climates with long, extremely cold winters that have 6-8 hours of sunlight. Summers are short, cool-warm temps, and up to 19+ hours of sunlight. Dominated by coniferous evergreen trees (spruce, fir, cedar) but have low plant diversity as few species can survive the winters when soil moisture is frozen.
• Partially decomposed conifer needles exist beneath these trees, and with the low temperatures + waxy coating on these needles + high soil acidity, decomposition is slow. These decomposing conifer needles kepe the topsoil acidic, preventing other plants (besides shrubs) from growing.
• Life includes bears, wolves, moose, lynx, and burrowing rodents. Lots of bugs too.

• 1.2 Billion people live in mountain ranges or their foothills, and 4 Billion people depend on mountain systems for all/some of their water. Their steep slopes allow for easy erosion as the vegetation holding them in place is removed by landslides, avalanches, or human activities (timber, agriculture).

• These mountains can be islands of biodiversity, surrounded by a sea of lower-elevation landscapes transformed by humans. We’re so cool.

• Play an Important Ecological Role: Containing a large portion of the world’s forests (which are habitats for much of the planet’s terrestrial diversity), they are often also habitats/sanctuaries for endemic species (species not found anywhere else on earth) and animals capable of migrating to higher altitudes and surviving there. Thanks to warming climate and human activities, more of these animals are driven to these mountain habitats from the lowland areas.

• Mountains also help to regulate the Earth’s climate; covered with glacial ice and snow, they reflect some solar radiation back into space, helping to cool the earth. However, when this ice melts, the rocks underneath absorb the solar radiation and heat up the atmosphere, thus melting more ice and causing a positive feedback loop.

• Mountains also help the hydrologic cycle by storing tons of water in the form of ice and snow. In the warmer weather of spring/summer, much of this ice/snow melts, releasing water to streams to be used by wildlife and by humans for drinking and irrigating crops. But increasing global temps causes earlier melting, lowering food production in certain areas (much of the water needed throughout the summer to irrigate crops is released too early and too quickly). Despite this issue, governments and many environmental organizations have not focused on these areas. sad.

• 60% of the world’s major terrestrial ecosystems are being degraded or used unsustainably; our ecological footprint gets bigger and bigger

• Many scientists call for a global effort to better understand the nature/state of the world’s major terrestrial ecosystems and biomes and to use such data to protect the world’s remaining wild areas from harmful forms of development. They also call to restore many of the degraded land areas, especially those rich in biodiversity.

• Differences in climate, based mostly on long-term differences in average temperature and precipitation, largely determine the types and locations of the earth’s deserts, grasslands, and forests.

• The earth’s terrestrial ecosystems provide important economic and ecosystem services.

• Human activities are degrading and disrupting many of the ecosystem and economic services provided by the earth’s terrestrial ecosystems.

Chapter 4 - Aquatic Biomes

4.1 - What is the General Nature of Aquatic Systems?

• They hold 98% of the earth’s water and are a third of the earth’s surface

• The distribution of organisms in these zones is determined by the water’s salinity (the amount of various salts dissolved in a given volume of water)

• Two Major Types of life zones
• Saltwater/Marine Life Zones: Include oceans, estuaries (contain both salt and freshwater, but scientists classify them as marine life zones), coastal wetlands, shorelines, coral reefs, and mangrove forests
• Freshwater Life Zones: lakes, rivers, streams, inland wetlands

• Plankton: a major type of organism present in both freshwater/saltwater life zones
• Phytoplankton: drifting organisms, including many types of algae
• Ultraplankton: the producers that make up the base of most aquatic food chains/webs. They’re even smaller than phytoplankton, and they produce half of the Earth’s oxygen.
• Zooplankton: feed on phytoplankton and other zooplankton. They range in size from single-celled protozoa to large invertebrates (jellyfish)

• Nekton: another major type of aquatic organism - strongly swimming consumers like fish, turtles, and whales

• Benthos: consists of bottom-dwellers (oysters, sea stars) that anchor themselves to ocean-bottom structures (clams/worms in sand, lobsters/crabs walking along sea floor)

• Decomposers: Mostly bacteria, they break down organic compounds into nutrients that the aquatic primary producers can use.

• Temperature

• Dissolved oxygen content

• Availability of food

• Availability of light/nutrients required for photosynthesis (Carbon as dissolved CO2, Nitrogen as NO3-, Phosphorus as PO43-)

• The depth of this zone is reduced due to increased turbidity (cloudiness caused by excess growth of algae - an algal bloom)

4.2 - Why are Marine Aquatic Systems Important?

• Oxygen through photosynthesis

• Water Purification

• Climate Moderation

• CO2 Absorption

• Nutrient Cycling

• Reduced Storm Damage

• Vital Part of the Water Cycle

• Biodiversity: species and habitats

• Food

• Energy from waves and tides

• Pharmaceuticals

• Harbors and Transportation routes

• Recreation/Tourism

• Employment

• Minerals

• Coastal Zone: the warm, nutrient rich, shallow water extending from the high tide mark to the sloping edge of the continental shelf (submerged part of the continents).
• Makes up <10% of ocean area but contains 90% of marine species + most large commercial fisheries
• Includes Estuaries, coastal marshes, mangrove forests, coral reefs

• Pelagic Zone (Open Sea): the water column of the open ocean. Low NPP except in upwelling areas, but because of its massive size, it makes the largest contribution to the Earth’s overall NPP. It is divided into three vertical zones/layers that vary in temperature based on the degree of sunlight penetration:
• Euphotic Zone: brightly lit upper zone, where drifting phytoplankton do 40% of the world’s photosynthesis. Large, fast-swimming predatory fish occupy this area too (swordfish, sharks, bluefin tuna).
• Nutrient Levels are low, Levels of Dissolved Oxygen are high (except in upwelling - upward movement of ocean water, bringing cool, nutrient rich water from the bottom of the ocean to the surface, supporting large populations of phytoplankton, zooplankton, fish, seabirds)
• Bathyal Zone: dimly lit middle zone receives little sunlight - no photosynthesizing producers. You can find zooplankton and smaller fishes in this zone; they migrate to feed on the surface at night.
• Abyssal Zone: The deepest ocean zone - it’s dark and cold with no sunlight and little dissolved oxygen, but very nutrient rich, allowing the ocean floor to be teeming with life. This zone’s organisms get their food from the dead/decaying organisms (marine snow) that drift down from the upper zones.
• Some are “deposit feeders” (taking mud into their guts and extracting its nutrients), while others are “filter feeders” (passing water through or over their bodies and extracting the nutrients in it).

• Ocean Bottom

• Freshwater Wetlands: swamps, marshes, bogs, fens, prairie potholes

• Marine Wetlands: estuaries, mangrove swamps, coastal marshes

• Provide important ecosystem/economic services: maintaining water quality in tropical coastal zones by filtering stuff (toxic pollutants, excess plant nutrients, sediments, absorbing other pollutants) and by providing food/habitats/nursery sites for many aquatic and terrestrial species. They also reduce storm damage and coastal erosion, absorbing waves and storing excess water.

• Associated with coastal wetlands (coastal land areas covered with water for all/part of the year) - coastal/salt marshes, mangrove forests.
• Have very productive ecosystems due to high nutrient input from rivers/land, tidal flow circulating nutrients rapidly, and ample sunlight penetrating its shallow waters.
• Seagrass Beds: another component of marine biodiversity, occur in shallow coastal waters, support a variety of marine species because of ample sunlight and plant nutrients that flow from the land

• Intertidal Zone: The area of shoreline between low and high tide
• To survive in this zone, organisms must avoid being swept or crushed by waves, being immersed or being left dry at high/low tides, and changing levels of salinity when heavy rains dilute water. They use protective shells, dig, or hold on tight.
• Thy have a a great variety of species, each occupying a different niche to deal with daily and seasonal changes in environmental conditions (temp, water flows, salinity)
• Steepy Rock shores pounded by waves, gently sloping barrier beaches/sandy shores, and barrier islands all have unique organisms.

• This + other forms of degradation could have devastating effects on the biodiversity and food webs of coral reefs, which will, in turn, degrade the ecosystem services that reefs provide.

4.3 - How have Human Activities Affected Marine Ecosystems?

• More than 35% of the world’s original mangrove forest area had been lost to agricultural/urban expansion, marinas, roadways, and other coastal development

• More than one of every 6 species of mangrove are in danger of extinction

• 29% of the world’s seagrass beds have been lost to pollution

• Human activities have affected 41% of the world’s ocean area

• About 45% of the world’s population lives along or near coasts

• Secondary Threat: Ocean Acidification. I’ve already talked about this, and how it’ll threaten coral reefs, phytoplankton, and many shellfish who rely on calcium carbonate.

• Coastal development, which destroys or degrades coastal habitats

• Runoff of pollutants such as fertilizers, pesticides, and livestock wastes and pollution from cruise ships and oil tanker spills

• Overfishing and depletion of commercial fish species populations

• Destruction of ocean bottom habitats by fishing trawlers dragging weighted nets

• Invasive species that deplete populations of native species

4.4 - Why are Freshwater Ecosystems Important?

• Climate Moderation

• Nutrient Cycling

• Waste Treatment

• Flood Control

• Groundwater recharge

• Habitat for many species

• Genetic resources and biodiversity

• Scientific information

• Food

• Drinking water

• Irrigation water

• Hydroelectricity

• Transportation corridors

• Recreation

• employment

• Vary in size, depth, and nutrient content

• Have 4 distinct live zones defined by their depth and distance from shore:
• Littoral Zone: Near the shore, consists of the shallow sunlit waters to the depth where rooted plants stop growing. High biodiversity bc ample sunlight and nutrients from surrounding land, and contain many rooted plants, frogs/turtles, and many fish.
• Limnetic Zone: open, sunlight surface layer away from the shore extending to the depth penetrated by sunlight. Main photosynthetic zone of lake (produces the food/oxygen that supports most of the lake’s consumers). Most abundant organisms: phytoplankton and zooplankton, with a few large species of fish spending most of their time here.
• Profundal Zone: volume of deeper water lying between the limnetic zone and lake bottom. Too dark for photosynthesis, and oxygen levels are low because of no plants/sunlight. Fishes adapted to the lake’s cooler, darker water.
• Benthic Zone: mostly decomposers, detritus feeders, some bottom-feeding species of fish (catfish). Nourished mainly by dead matter falling from the littoral/limnetic zones + sediment washing into the lake.

• Source Zone: shallow, cold, clear, fast headwater streams with large amounts of dissolved oxygen thanks to water tumbling over rocks/waterfalls. Not very productive because of a lack of nutrients and primary producers. Nutrients mainly from organic matter (leaves, branches, living/dead insects). Populated with cold-water fish that need lots of dissolved oxygen. They tend to have streamlined, muscular bodies helping them swim in these strong currents or compact, hard, flattened bodies to live among/under stones here. Most plants are algae and mosses.

• Transition Zone: merging of headwater streams to form wider, deeper, warmer streams flowing down gentler slopes w/ fewer obstacles. They’re more turbid (more suspended sediments) and slower with less dissolved oxygen. The warmer water + other conditions allow for more producers and more cool-water/warm-water fish species w/ lower oxygen requirements.

• Floodplain Zone: streams joining into wider, deeper rivers flowing across broad, flat valleys. Water is high temp, less dissolved oxygen, supporting large populations of producers (algae, cyanobacteria) and rooted aquatic plants along the shores.Water often muddy with lots of silt bc increased erosion and runoff over a larger area. Lots of fish supported, and at the water’s mouth, a river may divide into many channels as it flows through its delta (an area at the mouth of a river built up by deposited sediment)

• Coastal Deltas and Wetlands absorb/slow the velocity of flood waters from coastal storms/hurricanes/tsunamis and provide habitats

• Some are covered with water year-round, while seasonal wetlands remain under water/soggy for a short time each year (prairie potholes, floodplain wetlands, arctic tundra). Some stay dry for years.

• Highly productive bc abundance of nutrients.

• filtering and degrading toxic wastes and pollutants

• reducing flooding and erosion by absorbing storm water and releasing it slowly, and by absorbing overflows from streams and lakes

• sustaining stream flows during dry periods

• recharging groundwater aquifers

• maintaining biodiversity by providing habitats for a variety of species

• supplying valuable products such as fishes and shellfish, blueberries, cranberries, and wild rice

• providing recreation for birdwatchers, nature photographers, boaters, anglers, and waterfowl hunters.

4.5 - How have Human Activities Affect Freshwater Ecosystems?

• Dams and Canals restrict the flows of about 40% of the world’s 237 largest rivers
• This alters/destroys terrestrial and aquatic wildlife habitats along these rivers and in their coastal deltas and estuaries. They also lead to degraded coastal wetlands and greater damage from coastal storms.

• Flood Control Levees and dikes built along rivers disconnect the rivers from the floodplains, destroy aquatic habitats, and alter/degrade the functions of adjoining wetlands.
• Channelization - any type of engineering used to control or redirect a waterway, contributes greatly to the flow of sediments out to sea, rather than letting natural erosion and deposition occur in these ecosystems

• Cities and Farms add pollutants and excess plant nutrients to nearby streams, rivers, and lakes
• This can cause explosions in the populations of algae and cyanobacteria (eutrophication)

• Many inland wetlands have been drained or filled to grow crops or have been covered with concrete, asphalt, and buildings.
• Inland wetlands are disappearing, with many lost to mining, logging, oil and gas extraction, highway construction, urban development, and growing crops.

• RESULT: increasing flood damage, 90% of all inland wetlands in Germany/France destroyed

• Saltwater and freshwater aquatic life zones cover almost three-fourths of the earth’s surface, and oceans dominate the planet.

• The earth’s aquatic systems provide important ecosystem and economic services.

• Certain human activities threaten biodiversity and disrupt ecosystem and economic services provided by aquatic systems

Chapter 5 - Biodiversity

5.1 - What are the Major Types of Life on Earth?

• Eukaryotic Cells are the Building Blocks of the organisms that make up modern species.

• 2 Million species have been identified out of the world’s estimated 7-100 Million species.

5.2 - What is Biodiversity and Why is it Important?

• Species Diversity:  the # and abundance of different kinds of species living in an ecosystem.
• Species Richness: the number of different species in ecosystem
• Species Evenness: the relative abundance of all species in an ecosystem.

• Genetic Diversity: the variety of genes found in a population or in a species. High genetic diversity == better chance of surviving and adapting to environmental changes.

• Ecological Diversity: Earth’s diversity of biological communities (biomes - grasslands, deserts, mountains, forests, oceans, lakes, rivers, etc). They differ in their community structure based on the types, relative sizes, and stratification of their plant species.
• Edge Effect: The change in population of community structures that occur at the boundary of two habitats. present in large areas of forest and other biomes, they tend to have a core habitat/edge habitats with different environmental conditions and species.
• Ecotone: a region containing a mixture of species from adjacent ecosystems along with some migrant species not found in either of the bordering ecosystems. Higher species diversity in ecotones than the surrounding biomes.

• Functional Diversity: The variety of processes that occur within ecosystems as species interact with each other through food chains/webs (ex: energy flow, matter cycling)

1. Tropical Rainforest

2. Coniferous Forest

3. Deciduous Forest

4. Thorn Forest

5. Thorn Scrub

6. Tall-grass Prairie

7. Short-grass Prairie

8. Desert Scrub/Desert

9. Arctic Tundra

• Each species plays a specific ecological role, called its niche, in the ecosystems where it is found.

• As environmental conditions change, the genes in some individuals mutate and give those individuals genetic traits that enhance their abilities to survive and to produce offspring with these traits.

• The degree of balance between speciation and extinction in response to changing environmental conditions determines the earth’s biodiversity, which helps to sustain the earth’s life and our economies.

Chapter 6 - Biodiversity and Ecological Change

6.1 - How Does the Earth’s Life Change Over Time?

• Explains how the Earth’s life has changed and diversified over the past 3.8 billion years

• Involves a change in a population’s genetic makeup through successive generations. Populations evolve by becoming genetically different, NOT individuals evolving.

1. Development of Genetic Variability (a variety in the genetic makeup of individuals in a population): this occurs through mutations - changes in the coded genetic instructions in the DNA of a gene - in the reproductive cells. Those are the cells passed onto offspring.
1. These mutations can sometimes result in a new genetic trait (heritable trait).
2. Some mutations are beneficial, and some are harmful.
3. Genetic variability in a population means that they’re more resistant to change because there are more individuals with possible favorable traits, giving more chances of survival.

2. Natural Selection: explains how populations evolve in response to changes in environmental conditions. The individuals with advantageous traits that improve their ability to survive (ex: camouflage in the open desert - adaptive trait) are more likely to survive and reproduce.
1. Ex: genetic resistance (when 1+ organisms in a population have genes that can tolerate a chemical designed to kill them. When that chemical is used, only they survive and reproduce, and eventually, the entire population is resistant).
2. Selective Pressure/Force: the environmental condition that kills individuals without the favorable adaptation dictated by natural selection. Ex: birds are the selective pressure on beetles and stuff.
3. An organism’s habitat determines which traits are adaptations. This can change as environmental conditions change.
4. Species are usually incapable of adapting as fast as the environment changes; most will probably leave or die if a mass environmental change happens.

• Fossil Record: the total body of evidence (all the fossils). It’s uneven and incomplete because many past forms of life didn’t leave any fossils + some fossils decomposed

• It’s estimated that the fossils found represent only 1% of all the species that have ever lived.

• Strong Opposable Thumbs: allow us to grip and use tools better than the few other animals that have thumbs

• Ability to walk Upright: give us ability and frees up our hands

• A complex brain: allows us to develop many skills (talk, read, write, do calculus) to transmit complex ideas and information

1. Change in Environmental Conditions == adaptation only for genetic traits already present in a population’s gene pool.

2. A population’s ability to adapt may be limited by its reproductive capacity (species that reproduce fast can undergo natural selection fast. Species that take a long time to reproduce may take thousands or millions of years to adapt).

• Survival of the fittest == survival of the strongest.
• WRONG! Fitness == reproductive success.

• Evolution explains the origin of life.
• WRONG! It explains how species have evolved/diversified after life formed.

• Humans evolved from apes or monkeys
• WRONG! Fossil evidence shows that humans/apes/monkeys evolved along different paths from a common ancestor about 5-8 million years ago.

• Evolution by natural selection causes species to become perfectly adapted
• WRONG! Evidence shows that the forces of natural selection/random mutations can push evolution in a multitude of ways.

• Evolution by natural selection isn’t important because it’s just a theory.
• WRONG! It’s the best scientific explanation for the Earth’s biodiversity.

6.2 - What Factors Affect Biodiversity?

• The locations of continents and oceanic basins have greatly influenced the Earth’s climate, which therefore dictates where plants/animals can live and thrive.

• The breakup, moving, and joining of continents has allowed species to move and adapt to new environments

• Earthquakes cause fissures in earth’s crust that can separate and isolate populations of species on rare occasions. Over time, this can lead to the formation of new species.

• Volcanic eruptions (volcanoes stem from the drifting/collision of tectonic plates, and are located along the boundaries of tectonic plates) can also affect extinction and speciation by destroying habitats and reducing/isolating/wiping out populations of species.

• Geographic Isolation: when different groups of the same population of a species become physically isolated for a long time. This exposes the differing groups to different environmental conditions, which means that different traits are now more advantageous depending on the group.

• Reproductive Isolation: mutation and change by natural selection operate independently in the gene pools of geographically isolated populations. If this continues, members of isolated populations of sexually reproducing species can become different in genetic makeup, thus hindering their ability to produce live, fertile offspring if they are rejoined.

• The resulting population (which is smaller and randomly selected and less genetically diverse) is more vulnerable to future disturbances + doesn’t represent the original population’s genetic diversity.

• It’s not a form of speciation, and is limited to crossbreeding between genetic varieties of the same species.

• It’s given us food crops with higher yields, cows with more milk, and many different types of dogs/cats.

1. Identify a gene with the desired trait in the DNA found in the nucleus of a cell from the Donor organism.

2. Extract a small circular DNA molecule (plasmid) from a bacterial cell.

3. Insert the desired gene from Step 1 into the plasmid to form a recombinant DNA plasmid.

4. Insert this recombinant plasmid into a cell of another bacterium, which rapidly divides and reproduces large numbers of bacterial cells with the desired DNA trait.

5. Transfer the modified bacterial cells to a plant/animal that is to be genetically modified.
1. RESULT: a Genetically Modified Organism (GMO), with its genetic information modified in a way not found in natural organisms.

• Endemic Species (species found in only one area) are especially vulnerable, as they’re unlikely to be able to migrate or adapt to rapidly changing environmental conditions. Ex: many amphibians.

• Adaptation to the new conditions through natural selection

• Migration to another area with more favorable conditions

• Extinction.

• Provides opportunities for the evolution of new species that can fill unoccupied ecological niches or newly created ones -> every mass extinction is followed by an increase in species diversity, as new species rise to occupy new habitats or to exploit newly available resources.

• The largest cause of the rising rate of species extinctions is the loss, fragmentation, and degradation of habitats.

1. Larger Islands support more total species -> greater ecosystem diversity -> more food and habitat resources + more niches/roles that organisms can play in the ecosystem

2. Islands closer to the “mainland” support more species, as it’s easier for colonizing organisms to get to the island from the mainland. More colonizing organisms -> more genetic diversity.

6.3 - How Do Communities and Ecosystems Respond to Changing Environmental Conditions?

1. Primary Ecological Succession: gradual establishment of communities of different species in lifeless areas. Starts when there’s no soil in a terrestrial environment, or no bottom sediment in an aquatic environment -> bare rock exposed by retreating glacier, newly cooled lava, new river
1. Takes thousands of years because of the need to build up fertile soil/aquatic sediments to provide the nutrients needed for a plant community
2. Pioneer Species: species that quickly colonize the newly exposed land (lichens, mosses, often having seeds or spores that can travel long distances and quickly spread). These species release acids that can break down the rock and start the soil formation process.
3. Each successive wave of new organisms changes the environmental conditions in ways that provide more nutrients, habitats, and favorable environmental conditions for the next waves.

2. Secondary Ecological Succession: More common succession. It’s a series of terrestrial communities/ecosystems with different species developing in places containing soil or bottom sediment. Occurs where an ecosystem has been disturbed, removed, or destroyed, but with some soil/sediment remaining -> abandoned farmland, burned forests, polluted streams, etc.
1. New vegetation can grow within a few weeks, as some soil/sediment is already present.

• Important ecosystem service that can enrich the biodiversity of communities by increasing species diversity and interactions among species.
• These interactions enhance sustainability by promoting population control and increasing the complexity of food webs.
• Primary/Secondary ecological succession are examples of natural ecological restoration.

1. Pioneer Species: grows on bare rock (primary) or bare soil/sediment (secondary) after disturbance
1. Fast growing, tolerant of shallow soil and fill sunlight, seeds spread by wind or animals
2. In Primary: moss/lichen
3. In Secondary: grasses/sedges/wildflowers

2. Mid-Successional Species: grows on soil formed from pioneer species, full of nutrients from repeated cycles of growth and death
1. Relatively fast growing, larger plants that need deeper soils with more nutrients than pioneers, sun tolerant
2. Ex: shrubs, bushes, fast-growing trees (aspen, cherry, pine)

3. Climax Species: grows on deepened and enriched soil formed from prior stages
1. Large, slow-growing trees that are tolerant of shade and require deep soils for large root networks
2. Ex: maples, oaks, other large trees

1. Facilitation (one set of species makes an area suitable for species with different niche requirements while making it less suitable for itself -> lichens build up soil, allowing herbs and grasses to move in and crowd the lichens out)

2. Inhibition (one species hinders the establishment and growth of another species -> needles dropping from pine trees make the soil beneath it too acidic for plants to grow)

3. Tolerance (plants in the late stages of succession succeed because they’re not in direct competition with other plants for key resources -> shade-tolerant plants can live in shady forests because they don’t need as much sunlight as the trees above them do)

• Traditional:
• Ecological succession proceeds to stable climax communities
• Equilibrium is called the Balance of Nature.

• Current:
• Succession leads to a more complex, diverse, and resilient ecosystem
• Can withstand changes if not too large or sudden

1. Inertia/Persistence: the ability of an ecosystem to survive moderate disturbances

2. Resilience: the ability of an ecosystem to be restored through secondary ecological succession after a severe disturbance

• Ex: Tropical rainforests have high species diversity -> high inertia, but low resilience (if a large tract of it is cleared or severely damaged, the degradation may reach an ecological tipping point, where the forest might not be restored by secondary ecological succession)
• Low resilience probably because most of the nutrients are stored in the vegetation. Once the vegetation is cleared and the frequent rains remove the remaining nutrients in the soil, a tropical rainforest won’t come back to this area.

• Ex: grasslands have low species diversity -> low inertia, but very high resilience
• They can burn easily, so moderate disturbances are bad. But because most of their plant matter is stored in underground roots, they can recover quickly after a fire or something, because their root systems produce new grasses. Grasslands can only be destroyed by severe overgrazing or if its roots are plowed up and something is planted in its place.

• Periodic: occurs with regular frequency (dry-wet seasons)

• Episodic: occasional events with irregular frequency (hurricanes, droughts, fires)

• Random: no regular frequency - volcanoes, earthquakes, asteroids

Chapter 7 - Populations

7.1 - What Roles Do Species Play in Ecosystems?

• Narrow niche

• Smaller range of ecological tolerance
• SPECIFIC FOOD REQUIREMENTS - PICKY
• Low adaptability in new conditions

• More prone to extinction

• Has advantage in stable habitats

• Broad niche

• Larger range of ecological tolerance
• Nonspecific food requirements
• High adaptability in new conditions

• Less prone to extinction

• Has advantage in changing habitat

• Can spread rapidly, may not face the same predators/diseases that they faced in their native niches, may outcompete some native species in their new locations

• Ex: The American Alligator digs gator holes. These hold freshwater and serve as a refuge for aquatic life. In the 1930s they were hunted for sport, meat, and skin, and it harmed the subtropical wetland ecosystem they inhabited. They made an impressive comeback in 1977.

7.2 - What Limits the Growth of Populations?

• Vary in their distribution over their habitats (dispersion): some live together in groups, which allows organisms to cluster near resources + provides some protection from predators + gives some predator species a better chance of finding a meal.

• Increases With: birth and immigration (arrival of individuals from outside the population)

• Decreases With: death and emigration (departure of individuals)

• Described in terms of organisms in the pre-reproductive, reproductive, and post-reproductive stages.

• Individuals may vary in their tolerance ranges for temperature/physical/chemical factors because of small differences in their genetic makeup, health, and age, allowing for evolution through natural selection (wider tolerance == more fit)

• Optimal Range: range where the organism thrives, and can survive/grow/reproduce

• Zone of Physiological Stress: range where the organism survives, but experiences some stress (infertility, stunted growth, decreased activity)

• Zone of Intolerance: range where the organism will die (thermal shock, suffocation, lack of resources)

• Density Dependent: factors that become more important/severe as a population’s density increases (ex: disease, parasites, food)

• Density Independent: factors whose effect on the population isn’t exacerbated by a population’s density. (ex: natural disasters)

• Random (trees, resources are scattered)

• Clumped (herd, group animals, resources are in specific areas)

• Uniform (resources evenly distributed)

• Carrying Capacity (k): the maximum individuals in a population that an ecosystem can support due to limited resources/limiting factors (food, water, habitat space, disease). In the below graphs, Figure 2 is the realistic one.

• Overshoot: when a population exceeds carrying capacity
• Consequence: resource depletion, leading to die offs

• Die Off: resource depletion causes sharp population decline
• Consequence: population crashes (die back)

• Hard for population to recover after disturbance

• If parent dies, offspring will die

• Outcompeted by invasive species for resources

• Less likely to adapt, more likely to go extinct when facing environmental change

• Quick population recovery after disturbance

• If parent dies, offspring can still survive

• Likely to be the invasive species itself.

• More adaptable, lower chance of extinction

• Type 1: usually K selected. High survivorship early in life due to attentive, high parental care. High survivorship midlife due to large size and defensive behavior. But then it crashes. Because of old age.

• Type 2: in between K and r. Linear line, steadily decreasing survivorship throughout life

• Type 3: usually r-selected. Low survivorship early in life due to little/no parental care, few survive midlife, even fewer make it to adulthood

7.3 - How Many People Can the Earth Support?

• Less developed countries grow faster than more developed countries

• More people are moving from rural to urban areas

• Malthusian Theory: earth has a human carrying capacity, based on the linear growth of food production vs. the exponential growth of human population. TLDR: Humans will reach a carrying capacity limited by food.

• Technological Advancement: thanks to advances in technology, humans can alter Earth’s carrying capacity (ex: synthetic nitrogen fixation -> synthetic fertilizer -> dramatically increased food supply)

• Reducing biodiversity

• Increasing use of NPP

• Increasing genetic resistance in pest species and diseases-causing bacteria

• Introducing harmful species into natural communities

• Eliminating many natural predators

• Using some renewable resources faster than they can be replenished

• Disrupting natural chemical cycling and energy flow

• Relying mostly on polluting and climate-changing fossil fuels

• Despite there being a finite amount of this land, technological advancements and large fossil fuel usage in industrial agriculture has allowed food production to keep pace with population growth.

7.4 - What Factors Influence the Size of the Human Population?

• Crude Birth Rate: the number of live births per 1000 people in a population in a given year

• Crude Death Rate: the number of deaths per 1000 people in a population in a given year

• Replacement-level fertility rate: the average number of children that couples in a population must bear to replace themselves. It’s typically >2 because some children die before reaching their reproductive years (particularly in poorer countries)

• Total fertility rate (TFR): the average number of children born to the women of childbearing age in a population
• 1995-2017: Global TFR dropped from 5.0 to 2.5. Must drop to and remain at the replacement-level fertility rate to eventually halt population growth.

• Factors that Affect a Country’s Average Birth Rate/TFR:
• The importance of children as a part of the labor force: incentivises poor couples in developing countries to have many children, to help them haul drinking water, gather wood for heating and cooking, and grow/find food.
• The cost of raising and educating children: in more developed countries, raising children is more costly because they don’t enter the labor force until they’re in their late teens or twenties. As a result, birth/fertility rates are lower in developed nations.
• The Availability of Pension Systems: pensions reduce a couple’s need to have several children to replace those who die at an early age, reducing birth/fertility rates in undeveloped countries.
• Urbanization: people in urban areas generally have better access to family planning services and tend to have fewer children than those in rural areas.
• Educational/employment opportunities available for women: TFRs are low for women who have education/paid employment opportunities. In undeveloped countries, a woman with no education has approx. 2 more children than an educated woman.
• Average Age at Marriage: women normally have fewer children when their average age at marriage is 25 or older.
• Availability of reliable birth control methods: more developed countries/ urban areas have better access to contraceptives.
• Religious beliefs, traditions, cultural norms: some cultures say having many children is good. It’s not.

• Life Expectancy: key health indicator - the average number of years a person born in a particular year can be expected to live. 1955 -> 2017: 48 -> 72. Most affected by poverty, which can reduce lifespan by 7-10 years.

• Infant Mortality Rate: the number of babies out of every 1000 born who die before their first birthday. It’s one of society’s best measures of quality of life because it indicates the general levels of nutrition and healthcare. High rate == undernutrition or malnutrition (insufficient/poor food) and disease.

• Areas with lower infant mortality rates tend to have lower TFRs (women have fewer children because fewer of their children die at an early age)

• These rates have declined dramatically since 1965, but more than 4 million infants still die per year.

• Gross Domestic Product: key economic indicator - total monetary value of all goods and services produced in a country per quarter or year. Per capita == per each person, and GDP per capita == total GDP/total pop.
• High GDPs and Long Life Expectancies are indicators of development and low population growth.

• Higher TFR -> higher birth rate

• High infant mortality rate can drive up TFR (replacement children)

• High immigration

• Increased access to clean water, food, healthcare (decreased death rate)

• High death rate

• High infant mortality rate

• Increased development (education/affluence)

• Increased education for women

• Delayed age of first child

• Postponement of marriage age

7.5 - How Does a Population’s Age Structure Affect Its Growth or Decline?

• 0-14 Cohort > 15-44 Cohort: Current and Future Population Growth

• 0-14 Cohort = 15-44 Cohort: Current and Future Population Growth

• 0-14 Cohort < 15-44 Cohort: Current and Future Population Growth

• Slow decline is generally manageable

• Rapid decline leads to economic problems:
• Proportionally fewer young people working
• Labor shortages

• Other Problems Ensue:
• Can threaten economic growth
• Labor shortages
• Less government revenues with fewer workers
• Less entrepreneurship and new business formation
• Less likelihood for new tech development
• Increasing public deficits to fund higher pension/healthcare costs/social security
• Pensions may be cut and retirement age increased

7.6 - How Can We Slow Human Population Growth?

• Poverty declines as industrialization increases. Then, population growth slows.

• Threats to this transition include: extreme poverty and war, environmental degradation and resource depletion

• The Process of economic and social transition from an agrarian (farming) economy to an industrial (manufacturing) economy.

• Stages:
• Pre-Industrialized Less Developed: a country that has not yet made the agrarian to industrial transition. Low GDP (poor), high death rate, high infant mortality, high TFR for replacement children and extra child labor force.
• Industrializing Developing: partially through transition, rising GDP, decreasing death rate and infant mortality
• Industrialized Developed: completed transition. Very high GDP (rich), very low death rate and infant mortality, and low TFR (more opportunities)

• Pre-Industrial:
• High infant mortality and high death rate due to lack of access to clean water, stable food supply, healthcare, modern amenities.
• High TFR due to:
• Lack of access to education and contraceptives to women
• Need for child labor force (agricultural labor)
• Little to no population growth due to high CBR and CDR (birth/death rates) balancing each other out

• Industrializing/Developing:
• Declining infant mortality and death rate due to clean water, stable food supply, increasing healthcare
• TFR is high because:
• Lack of access to education
• Lack of access to contraceptives or family planning
• Need for child labor force (agricultural labor)
• Generational lag (time it takes for education/societal change to spread)
• Population Momentum (babies still need to grow up!)
• Rapid growth due to high CBR and declining CDR
• Indicators: Low GDP per capita, shorter life expectancy, high infant mortality, low literacy rate, low school life expectancy for girls

• Industrialized/Developed:
• Modernized economy and society increased family income, so TFR tends to decline due to:
• More educational opportunities for women
• Access to contraceptives or family planning
• Delayed age of marriage and first child to focus on education and/or career
• Slowing growth rate as CBR drops closer to CDR
• Indicators: high GDP per capita, long life expectancy, low infant mortality, TFR near replacement level (2.1), high literacy rate and school life expectancy for all

• Post-Industrialized/Highly Developed
• Highly modernized countries that are very affluent
• TFR declines even further as families become more wealthy and spend even more time on educational and career pursuits
• Increased wealth and education brings even more prevalent use of family planning and contraception
• CBR drops lower than CDR and population growth becomes negative -> pop decline!
• Indicators: very high GDP per capita, longest life expectancy, TFR below replacement level (2.1), highest contraceptive use rates

• Stage 5: Theoretical
• Birth rate rises again, death rate low, natural increase is stable or slow.

Chapter 8 - Land and Water Resources

8.1 - What are the Earth’s Major Geological Hazards?

• Core: A dense mass of solid nickel, iron, and radioactive elements releasing massive amounts of heat.

• Mantle: Liquid layer of magma surrounding core, kept liquified by the intense heat from the core.

• Asthenosphere: Solid, flexible outer layer of mantle, beneath the lithosphere

• Lithosphere: thin, brittle layer of rock floating on top of the liquid/molten mantle. This is broken up into Tectonic Plates: huge rigid plates that compose the lithosphere. They formed due to the flows of energy/heated material within the Earth’s convection cells, and the plates move extremely slowly (approx. the speed of fingernail growth) atop the asthenosphere.

• Crust: very outer layer of the lithosphere, earth’s surface

• Magma flows up from where the plates separate, forcing the plates to separate too.

• Forms: mid-oceanic ridges (chain of underwater mountains), volcanoes, seafloor spreading, rift valleys (on land)

• Convection Cycles:
• Magma heated by earth’s core rises towards lithosphere,
• Magma cools and expands which forces oceanic plates apart
• Creates mid-ocean ridges, volcanoes, spreading zones/”seafloor spreading”
• magma cools and solidified into new lithosphere,
• spreading magma forces oceanic plate and continental plate - subduction due to convergent boundary.

• Forms: mountains, island arcs, earthquakes, volcanoes

• When both plates rise, this forms mountain ranges. When one plate slides beneath the other, it melts and makes new magma that can rise through cracks and form volcanoes, while the overriding plate is pushed up and becomes mountainous terrain.

• Convergent Boundary Subduction Zones:
• Oceanic Oceanic: dense oceanic plate sinks - forces magma up to lithosphere surface, forming mid-ocean volcanoes -> magma arcs, or an off-shore trench
• Oceanic-Continental: dense oceanic plate sinks under continental plate and melts into magma - forces magma up to lithosphere surface, which may form mountains.
• Continental-Continental: one plate sinks under the other, forcing surface crust upward - mountains!

• Eruptions release chunks of lava rock, liquid lava, glowing hot ash, and gases. They are extremely explosive and destructive, but can be slower and much less destructive with lava spreading slowly across the land/sea floor. Slower eruptions form cone-shaped mountains.

• Eruptions can form majestic mountain ranges and lakes, and lava weathering creates fertile soils.

• Seismic waves move upward/outward from the Earthquake’s focus.

• We measure the severity of an Earthquake through the magnitude of its seismic waves (the shaking caused by the earthquake - amplitude of the seismic waves - measured by a seismograph)

• Seismologists measure earthquakes using the Richter Scale, where each unit has an amplitude 10 times greater than the unit before it. <4.0: Insignificant, 4.0-4.9: minor, 5.0-5.9: damaging, 6.0-6.9: destructive, 7.0-7.9: major, >8.0: great

• Primary Effects: shaking or a permanent vertical/horizontal displacement of a part of the crust.

• Also named tidal waves for some reason. They travel really fast and their waves can be far apart with their crests not very high. As it approaches shallower coasts, the wave crests squeeze closer together, their heights grow rapidly, and it hits the coast as a series of towering walls of water.

8.2 - What Processes lead to Soil Formation?

• Physical: wind, ice wedging, force of water breaking apart rock

• Chemical: acidic rain water reacting with rock minerals, producing soluble salts

• O: Leaf Litter/layer of organic matter on top of soil. This provides nutrients and limits H2O lost due to evaporation.

• A: topsoil
• Both the O and A horizon have the majority of organic matter and the roots of most plants. These layers teem with bacteria, fungi, earthworms, small insects, etc. in a fertile soil. They also have larger animal habitats (snails, reptiles, moles)
• Topsoil has billions of bacteria and other decomposers.
• A fertile soil would have a thick topsoil layer with a lot of humus mixed with minerals from weathered rock
• Black/dark brown topsoil is rich in nitrogen and organic matter while gray/bright yellow/ red topsoil is low in organic matter and needs nitrogen to support most crops.

• B: subsoil - lighter layer below the topsoil, mostly made of minerals with little to no organic matter and some nutrients

• C: weathered parent material
• These two layers contain most of the soil’s inorganic matter (broken down rock w/ sand, silt, gravel, and clay. The C-horizon sits on the soil’s parent material (bedrock)

• Deserts, for example, are warm but have little water and sparse vegetation so there’s no organic material that can become humus. Cold climates have limited liquid water and slow bacterial action.

• Tropical rainforests are wet and warm and very biodiverse but there’s intense competition for nutrients released by decomposition, so the soils there have little organic matter in the upper horizon and, therefore, low fertility.

• Factors Affecting Soil Formation:
• Parent Material: soil pH, nutrient content
• Topography: steep = too much erosion, flat = deposition
• Climate: warmer = faster breakdown of organic matter. More precipitation = more weathering, erosion + deposition.
• Organisms: soil organisms (bacteria, fungi, worms) break down organic matter

• Loss of Topsoil: tilling (turning soil for agriculture) and the loss of vegetation disturb soil and make it more easily eroded by wind and rain, drying out soil, removing nutrients and soil organisms.

• Compaction: compressing soil with machines, grazing livestock, and human activity, reduces a soil’s ability to hold moisture, drying it out. Dry soil erodes more easily and supports less plant growth/root structure -> more erosion.

• Nutrient Depletion: repeatedly growing crops on the same soil removes key nutrients over time, reducing ability to grow further crops

• Soils with more clay are more fertile, as clay particles often have a negative charge and bind with positively charged nutrient ions (Ca+, K+)

• There’s a direct relationship between porosity and permeability. More porous == more permeable.

• Nutrients: N, P, K+, Mg2+, Ca+, Na+
• Factors that Increase soil nutrients: organic matter (releases), humus (holds and releases), decomposer activity, clay, bases
• Factors that decrease: acids leaching positively charged nutrients, excessive lain/irrigation, excessive farming depleting nutrients, topsoil erosion.

• Water: needs to hold water, but not too much
• Factors that Increase H2O Holding Capacity: aerated soil, compost/humus/organic matter, clay content, root structure
• Factors that Decrease: compacted soil (livestock/machines), topsoil erosion, sand, root loss

• Effects on Soil Fertility: Soil that’s too sandy is too permeable - water drains too quick for roots + soil dries out. Clay-heavy soil isn’t very permeable - H2O doesn’t drain to roots or waterlogs, suffocating plants. Loam is best, because it balances porosity with H2O holding.

8.3 - Will We Have Enough Usable Water?

• Isn’t readily available: 0.024% of total water supply on Earth (groundwater, lakes, rivers streams)

• It moves in the seas, land, and air through the hydrologic cycle. However, water is distributed unevenly around the world.

• Is altered by humans, who withdraw and pollute the water as well as cause climate change.

• One of the Earth’s most important natural resources, vital for producing food and energy.

• However, it’s used inefficiently, commonly polluted, has low cost (incentivizing waste), and not accessible to many people (4k die daily due to lack of safe drinking water)

• Unconfined aquifers (aquifers whose water table is at atmospheric pressure AKA there’s some air left, and water can rise and fall) recharge quickly

• confined aquifers (an aquifer below the land surface that’s saturated with water) recharge slower due to being long term water deposits.

• ⅔ of surface runoff lost to seasonal floods

• The remaining ⅓ is the reliable source of freshwater.

• Worldwide Average Usage: 70% for irrigation of crops/livestock, 20% for industrial use, 10% for cities and residences.

8.4 - Is Groundwater a Sustainable Resource?

• Advantages:
• Useful for drinking and irrigation
• Exists everywhere
• Renewable if not over pumped or contaminated
• Cheaper to extract than more surface waters

• Disadvantages:
• Aquifer depletion from overpumping
• Sinking of land from overpumping
• Some deeper aquifers are nonrenewable
• Pollution of aquifers lasts decades or centuries

• Limits food production and raises prices

• Widens gap between rich and poor

• Land subsidence (sinkage)

• Groundwater overdrafts near coastal regions
• Contamination of groundwater with saltwater

8.5 - How can we Increase Freshwater Supplies?

• ½ to ⅔ of water is wasted from evaporation, leaks, and inefficient use. So we must cut water waste!!

• Government Subsidies mask the true cost of water. Use full cost pricing! Establish lifeline rates so the poor aren’t hurt!

• Slow Population growth

• Protect aquifers, forests, and other ecosystems that store and release freshwater

• Desalination: Turning seawater to freshwater
• Methods: Distillation (heats sea water to produce steam and collect freshwater) or Reverse Osmosis (applying high pressure to force sea water from one chamber into another through a semipermeable membrane that separates the salt)
• More than 17 desalination plants currently operating in 150+ countries
• Issues: high costs, high energy use, large amounts of salty wastewater.

• Aqueducts: Transferring water from one place to another.
• Ex: CA State Water project picks up water from Lake Oroville on the Feather River to 25 million people and 750k acres of farmland.
• Issues: water loss through evaporation and leaks, causes ecosystem degradation
• Diverting Water from the Aral Sea has led to wetland destruction, desertification, increased salinity, fish extinctions, blowing salt and dust destroying wildlife/crops, and increased glacial melting. It’s altered the local climate too. But restoration efforts are at hand.

• Reservoirs (Dams): Can generate hydroelectric power. By creating an artificial lake behind the dam, it can expand water supply in some areas. Damming rivers allows operators to allow more/less water through the channel, increasing or decreasing energy production.
• Reservoirs can provide irrigation water above and below it (in the bottom of a dam), provide water for drinking and recreational use, can produce cheap electricity, and reduce downstream flooding of cities and farms. Plus, it increases the reliable runoff available for use.
• Issues: Impairing ecological services of rivers, endangers plant and animal species, large losses due to evaporation, deprives downstream cropland/estuaries of nutrient-rich silt, risk of failure and flooding, disrupts migration of fish species.
• They can kill an estuary.
• Ex: Only a small amount of Colorado River water reaches the Gulf of California, threatening the aquatic species in the river and species that live in the estuary. The current rate of river withdrawal isn’t sustainable, and irrigation water is being used inefficiently.

8.6 - What is the Nature of the Atmosphere?

• Nitrogen: 78%, mostly as N2

• Oxygen: 21%, produced by photosynthesis and needed for human/animal/plant respiration

• Argon: 0.93%, inert and noble gas

• Water Vapor: 0-4%, varies by region and conditions, acts as temporary greenhouse gas but not as severe as CO2, quickly cycles through atmosphere

• Carbon Dioxide: 0.04%, most important GHG, leads to global warming, removed by photosynthesis

• Minute Traces of: Neon, helium, methane, krypton, hydrogen, xenon, ozone (O3)

• Exosphere: Outermost layer

• Thermosphere: therm = hottest temperatures here
• Absorbs harmful X-rays and UV rays
• Charged gas molecules glow under intense solar radiation, producing aurora borealis

• Mesosphere: meso = middle, even less dense

• Stratosphere: Second layer, less dense due to less pressure from layers above.
• Thickest Ozone (O3) layer here, absorbs UV-B and UV-C rays, which can mutate the DNA of animals -> causes cancer

• Troposphere: tropho = change (weather occurs here)
• Most dense due to pressure of other layers around it
• Most of atmosphere’s gas molecules are found here
• Where we’ll find planes, hot air balloons, etc
• Ozone in this layer is harmful to humans - respiratory irritant, damages plant stomata, forms smog

• Shift north and south as they follow boundaries of hot and cold air

• In both hemispheres, jet streams blow west to east.

• Below the jet stream, you’ll find the greenhouse gases.

• Thermosphere: temp increases due to absorption of highly energetic solar radiation

• Mesosphere: temp decreases as density decreases - fewer molecules to absorb sun rays (coldest place on earth)

• Stratosphere: temp increases as top layer of stratosphere is warmed by UV rays

• Troposphere: temp decreases as air gets further from the warmth of the earth’s surface (crust)

8.7 - What Factors Influence Weather?

• Moving masses of warm/cold air

• Atmospheric pressure changes

• Occasional shifts in major winds

• Wind is the movement of air from a region of high pressure to a region of low pressure.

• Its main cause is the unequal heating of the earth - as the sun heats the surface, hot air rises, leaving low pressure areas.

• Air cools as it rises and forms clouds, causing high pressure areas in the sky. Cold air sinks, and this high/low pressure difference causes air in the form of wind to flow into this partial vacuum.

• Maritime: Humid

• Continental: dry

• Arctic: cold

• Polar: cool

• Tropical: warm

• In a warm front, warm air moving in rises over denser, cold air.

• In a cold front, cold air moving in wedges (pushes) warm air upward.

• Warm Air rises, holding more moisture than cold air

• Rising air expands and cools

• Cold air can’t hold as much water vapor, which condenses into rain

• After cooling and expanding, air sinks.

• Air at 30° moves back to low pressure of equator
• North: deflects to right towards equator
• South: deflects to left towards equator

• 0-30°: Wind moves East to West because Earth spins from West to East.

• 30-60°: Wind moves West to East because Earth spins faster at 30° than at 60°.

• High pressure at 30° pushes air to low pressure at 0° and 60°
• Air rises at 0° and 60° due to low pressure
• Air sinks at 30° due to high pressure

• 0°-30° winds blow East to West -> Easterlies
• Ex: Northeasterly and Southeasterly Trade Winds. This also causes the ocean current to turn clockwise in the North hemisphere, and counterclockwise in the South hemisphere.

• 30° to 60° winds blow West to East -> Westerlies
• This drives the weather patterns of North America.

• E-W Easterly trade winds between 0-30° push equatorial currents East to West.

• Westerlies between 30-60° push mid-latina currents West to East.

• Upwelling Zones: ocean regions where winds blow warm surface water away from a landmass, allowing cold, deeper water to move up and replace it. This brings oxygen and nutrients to the surface.

• Warm water from the Gulf of Mexico moves towards the North pole, cooling and evaporating as it moves.

• Once it reaches, it’ll be saltier and denser, so it’ll sink and travel and spread along the ocean floor.

• Eventually, itll rise back up into shallow warm ocean currents at various upwelling zones.

• Impact: helps to mix the ocean waters, preventing the salt nutrients from settling on the colder, denser bottom of the ocean while keeping the warm surface waters from sitting still and preventing the mixing of deeper waters.

• Influenced by geological and geographical factors affecting different locations in different ways.

• El Niño Effects:
• Suppressed upwelling and less productive fisheries in SA
• Warmer winter for most of NA
• More precipitation and flooding in the Americas, especially the west coast
• Less hurricane activity in the Atlantic
• Drought in SE Asia/Australia
• Les Monsoon activity in India/SE Asia

• La Niña Effects:
• Stronger upwelling and more productive fisheries in SA than normal
• Cooler, drier weather in the Americas
• More tornado (US) and hurricane (Atlantic) activity.
• Rainier, warmer SE Asia
• More monsoon activity in SE Asia

8.8 - What Factors Influence Climate?

• Incoming solar energy

• Earth’s rotation

• Global air/water movement patterns

• Atmospheric Gases

• Earth’s surface features

• Cyclical air movement driven by solar energy

• Uneven heating of earth’s surface

• Latitude variation

• Earth’s axis tilt and resulting seasonal changes

• Earth’s rotation

• Ocean currents distributing sun's heat

• Radiation intensity is determined by the angle (how directly rays strike the earth’s surface) of the sun’s rays and the quantity of rays that pass through. The shape of the earth causes the latitude that is directly horizontal to the solar radiation to have the most intensity

• Highest solar radiation per unit area at the equator, decreases towards the poles

• Solar radiation received at a location on the Earth’s surface varies seasonally - because of the orbit of the Earth around the sun and the axis tilt changes depending on the season-with the most radiation received during the location’s longest summer day, and the least on the shortest winter day.

• Urban Heat Island: urban areas are hotter than rural areas bc low albedo of manmade materials

• Also, Geography:
• Mountains: Disrupt wind and produce rain shadow effect (warm, moist air from the ocean hits the windward side of the mountain, rising and cooling and condensing, forming rain and lush, green vegetation on that side. Dry air descends the leeward side of the mountain, warming as it sinks, causing arid/desert conditions.
• Oceans: moderate temperature and add moisture to the air

Chapter 9 - The Environment and Sustainability

9.1 - What are some Key Principles of Sustainability?

• Ecosystems: A set of organisms within a defined habitat that interact with one another and their environment. These ecological interactions take place in the biosphere, the parts of the earth where life is found.

• Dependence on Solar Energy: The sun’s energy warms the planet and provides energy for plants, who produce nutrients that we require to survive.

• Biodiversity: The variety of genes, species, ecosystems, and ecological processes that provide vital ecosystem services, keep populations from growing too large, and provide ways for species to adapt to changing environments

• Chemical (Nutrient) Cycling: The chemicals or nutrients (soil, water) needed to sustain life from the environment through various organisms and back to the environment.

1. Inexhaustible/Perpetual Resources: Expected to last for a long, long time (ex: solar energy)

2. Renewable Resources: Resources that can be replenished within hours to decades (a reasonable time frame).
• Sustainable Yield: The highest rate at which people can use a renewable resource indefinitely without depleting it

3. Non Renewable/Exhaustible Resources: Exist in a fixed amount (stock), taking millions to billions of years to form through geological processes (not a realistic time frame).

• Nutrient Cycling: A scientific principle of sustainability and a vital ecosystem service.

• Full-Cost Pricing: Including the harmful environmental/health costs of producing and using goods/services in their market prices

• Win-win Solutions: Using cooperation and compromise to benefit the largest number of people as well as the environment

• Responsibility to Future Generations: It’s our responsibility to leave Earth’s Life support system in a condition that is as good or better than how it is now.

9.2 - How are our Ecological Footprints Affecting the Earth?

• We can degrade or sustain the Earth’s life-support system in many, many ways.

• We’ve developed so many useful materials and products, harnessed much of the Earth’s resources, and basically controlled the planet.

• Carbon Footprint: The amount of carbon compounds (e.g. CO2) emitted by a person/city/country due to burning fossil fuels. Us humans have a lot.

• Globally, lifespans are increasing, infant mortality is decreasing, education is increasing, diseases are being conquered, and population growth has slowed!

• We are living unsustainably, and we do a lot of Environmental (Natural Capital) Degradation (wasting, depleting, and degrading much of the Earth’s life sustaining natural resources)

• Human activities directly affect 83% of Earth’s land surface, shrinking renewable forests, increasing deserts, eroding topsoil, lowering the lower atmosphere, causing glaciers to melt and increasing the intensity of natural disasters, and species are dying.

• This evaluates the biocapacity (ability) of the earth’s productive ecosystems to regenerate these renewable resources used by a population/city/area within a given year (ex: per capita ecological footprint - average ecological footprint of an individual in a given area).

• Agricultural Revolution (10k years ago) transformed us from hunter-gatherers to breeding plants and animals for food, clothing, and other purposes, giving us a more reliable source of food, helping us live longer, and helping produce more surviving children

• The Industrial-Medical Revolution (300 years ago) involved the creation of machines for the large-scale production of goods in factories, causing many to move from rural areas to cities. This involved learning how to extract fossil fuel energy, and how to grow large, efficient crop quantities.

• Information-Globalization Revolution (50 years ago) helped us gain rapid access to all kinds of information and resources on a global scale

• Sustainability Revolution: A potential fourth major cultural change that would involve us learning to live more sustainably by not degrading/depleting the vital natural capital that supports our lives and economies.

9.3 - Why do we have Environmental Problems?

• Population Growth

• Wasteful/unsustainable resource use

• Poverty

• Omission of harmful environment/health costs in market prices

• Increasing isolation from nature

• Competing environmental worldviews

• In 2012, 5 Earths would be needed to sustain the world’s population at the US average per capita resource consumption rate

• Having more children may be a matter of survival, as they help those in poverty gather firewood, haul water, and tend crops/livestock, as well as support them in their old ages (no social security, health care, retirement funds), etc. This is why the population growth rates in poor countries are high.

• Environmental degradation can lead to malnutrition, illness (lack of access to adequate sanitation/ clean drinking water)

• Reduce malnutrition and infectious diseases

• Provide universal primary school education for all children and for all of the world’s illiterate adults

• Reducing population growth by elevating the social/economic status of women, reducing poverty, and providing access to family planning

• Make small, low-interest loans to poor people who want to increase their income.

• With the main goal of maximizing profits, companies rarely do this.

• Planetary Management: Humans managing nature mostly for their own benefit

• Stewardship: Humans managing nature for their benefit and for the rest of nature

• Environmental Wisdom: Learning how nature has sustained life for 3.8 billion years and integrating these lessons from nature into our actions

• Using a shared or open-access renewable resource at a rate well below its estimated sustainable yield

• Converting open-access renewable resources to private ownership in order to be inclined to “protect your investment”

9.4 - What is the Role of Economics?

• Natural Capital: Resources and ecosystem services produced by the Earth’s natural processes that support all life and all economies.

• Human Capital: Physical/mental talents of the people who provide labor, organizational/ management skills, and innovation.

• Economic Growth: An increase in the capacity of a nation/state/city/company to provide goods and services to people

• Environmental scientists and economics call for phasing out these harmful subsidies and replacing them with environmentally beneficial subsidies and tax breaks, going to businesses involved in pollution and waste prevention, sustainable forestry and agriculture, conservation of water supplies, efficient and renewable energy improvements, and measures to slow climate change

• Instead of taxing wages and profits, economists are also calling for taxing pollution and wastes. Lower taxes on income, labor, and wealth, and raised taxes on harmful environmental activities would help.

• Biodiversity: Genetic, species, and ecosystem - higher biodiversity means healthier ecosystems while declining biodiversity can indicate pollution, habitat destruction, and climate change

• Food Production: Ability of the Earth’s soil, water, and climate to support agriculture. Major threats include climate change, soil degradation, and groundwater depletion, and increased meat consumption too.

• Atmospheric Temperature and CO2: Life depends on a narrow temperature range, and CO2, being a GHG, traps infrared radiation and warms the atmosphere. Deforestation and fossil fuel burning increase CO2 too. TLDR, increased CO2 is unsustainable, as it dries out farmable land, destroys habitats, and worsens storm intensity/ climate.

• Human Population and Resource Depletion: as the human population grows, resource depletion grows, and our resources are already harvested unsustainable from natural ecosystems, degrading ecosystem health (more paper = deforestation, more food = deforestation, soil erosion, and groundwater depletion, more travel = fossil fuel mining, air water and soil pollution, and habitat destruction)

9.5 - What is the Role of Government?

• These kinds of laws have provided millions of jobs and profits from many new technologies for reducing pollution and environmental degradation.

• Ecologists and many economists call for governments to increase their efforts for providing environmental security (as well as military and economic security), as well as recognizing that all 3 are interrelated.

• Without policy, natural capital would be degraded or destroyed, and our economy, dependent on natural capital, would ultimately collapse.

9.6 - What is an Environmentally Sustainable Society?

• Learn from nature

• Protect natural capital

• Don’t waste resources

• Recycle and reuse nonrenewable resources

• Use renewable resources no faster than nature can replenish them

• Incorporate the harmful health/environmental impacts of producing and using goods and services in their market prices

• Prevent further ecological damage and repair past damage

• Cooperate with one another to find win-win solutions to the environmental problems we face

• Accept the ethical responsibility to pass the Earth that sustains us on to future generations in a condition as good as or better than what we inherited

• We can ensure a more sustainable future by relying more on solar energy/ other renewable energy sources protecting biodiversity through the preservation of natural capital, and avoiding the disruption of the Earth’s vital chemical cycles

• Full-cost pricing is a major goal for achieving a sustainable future

• By committing ourselves to finding win-win solutions to the Earth’s environmental problems and to leaving the planet’s life-support system in a better shape than it is now, we will benefit ourselves and our future generations

• Population growth rate would be optimal; not too slow, not too quick

• Enough fish are left after the harvest to repopulate the population

• It doesn’t deplete the resource!

• Privatization and government regulation are ways to help preserve commons. Privatization isn’t preferred for the conservation of water resources or the species within them, because water sources are constantly mixing and moving.

• When determining if food is sustainable, you must take into account the number of fossil fuels used to produce, process, transport, and store the food; the number of herbicides, pesticides, and antibiotics used; the amount of water pollution; and the depletion of soil nutrients and water sources.

• Locally raised food uses less fuel to transfer the food to the market (bc it’s local - closer!), and grass-fed animals are best because no fuel, land, or water is being used to grow crops to feed the animals

Chapter 10 - Renewable Resource Use

10.1 - How Should We Manage and Sustain Forests and Public Lands?

• Super biodiverse because they’ve been allowed to undergo the later stages of ecological succession, providing niches to a multitude of wildlife species

• Benefits: Can provide wood rapidly + can supply most of the wood used for industrial purposes (paper, construction -> protects old-growth and second-growth forests)

• Occupy 7% of the world’s forest Area

• Downsides: less biologically diverse, less sustainable, not as much wildlife habitat or ecosystem services as diverse natural forests have, repeated cutting and planting can deplete nutrients in soil

• Provides ecosystem services far greater in value than the value of wood and other raw materials -> since 1997, the world has been losing $20.2 Trillion worth of ecosystem services from forests per year

• Full-Cost Pricing is a necessity in prices of forest goods and services + halting government subsidies that hasten their destruction, protecting old-growth forests, and sustainably harvesting trees

• Cover approx. 30% of land area, support more than 80% of US wildlife species and contain ⅔ of US surface water

• Energy flow

• Chemical Cycling

• Reduced Soil Erosion

• Absorbing/Releasing Water

• Purifying water and air
• Stomata (leaf pores) remove VOCs, NO2, PM from air and store in tree

• Influencing local/regional climate

• Storing atmospheric carbon
• This also helps to stabilize atmospheric temperatures

• Providing numerous wildlife habitats
• Up to ⅔ of the world’s terrestrial species, as many live in forests (biodiversity, ecotourism)

• Fuelwood, lumber

• Pulp for Paper

• Mining

• Livestock Grazing

• Recreation

• Jobs

• Ex: 0% Discount Rate == $10 Million Dollars worth of trees in 2015 will be $10 Million Dollars in 2045. 10% Discount Rate == $10 Million worth of trees in 2015 will be $10k in 45 years.

• Selective Cutting: intermediate to mature-aged trees are cut singly or in small groups

• Clear Cutting: removing all trees in an area
• Soil Erosion: caused by the loss of stabilizing root structure, this removes soil organic matter and nutrients from the forest while depositing soil sediments in local streams, warming the water and making it more turbid (cloudy)
• Increased Soil/Stream Temperatures: without tree shade, soil temperature increases, with its lower albedo than the leaves of trees (absorb more sunlight). Plus, the loss of tree shade along streams and rivers warms them as well, and the increased turbidity of these waters contributes to increased warming.
• Flooding and Landslides: logging machinery compacts soil, increased sunlight dries out soil, loss of root structure causes the erosion of topsoil and organic matter -> decreased water holding capacity of soil, causing water to accumulate on top and forming floods and landslides

• Strip Cutting: clear-cutting in strips

• Water pollution and soil degradation from erosion

• Acceleration of flooding

• Local extinction of specialist species

• Habitat loss for native and migrating species

• Reduced air filtration and carbon storing
• Cutting trees releases CO2 from decomposition of leftover organic material

• Slash and Burn (cutting trees and burning them for agriculture space) releases Greenhouse gases into the atmosphere (CO2, N2O)

• Forestry that minimizes damage to ecosystem (habitat destruction, soil erosion, etc)

• Selective or Strip Cutting: only cutting some of the trees (biggest/oldest) in an area to preserve habitat and topsoil

• Using Human/Pack Animal Labor to minimize soil compaction from machinery

• Replanting same species being logged

• Maximizes long-term productivity of land and preserves forest for future generations

• Use Recycled wood or repurpose wood without recycling (reuse -> furniture, decoration)

• Wood chips can be used for mulch for gardens or agricultural fields

• Reforestation: replanting of trees in areas that have been deforested

• Selectively Removing diseased trees to prevent spread of infection through entire forest
• This removes the host for disease and decreases density, making the spread less likely

• Release nutrients stored in dead biomass while burning other flammable material to make future fires less likely/destructive

• Controls destructive pest species and insects while allowing for the germination of seeds for some tree varieties (lodgepole pines, giant sequoia)

• Due to climate change, the fire season is getting longer.

1. Stopping Natural Fires
1. Putting out all natural forest fires as soon as they start

2. More Biomass Buildup
1. Immediate fire suppression == more biomass == more fuel for future fires

3. Monitoring Instead
1. Cann prevent fire damage and worse future fires

1. Dead Biomass Builds Up
1. Dead biomass is fuel. There are nutrients in biomass.
2. Dead trees also may have disease and pests.

2. Small, Controlled Fires Burn this Biomass
1. Uses up dead biomass as fuel, preventing larger forest fires later

3. Nutrient Cycling Happens!
1. Nutrients in dead biomass are recycled

• Protect the most diverse, endangered areas

• Educate settlers about sustainable agriculture and forestry

• Subsidize only sustainable forest use

• Protect forests through debt-for-nature swaps and conservation concessions

• Certified sustainably grown timber

• Reduce poverty and slow population growth

• Encourage regrowth through secondary succession

• Rehabilitate degraded areas

• Concentrate farming and ranching in already-cleared areas (make tree plantations only in deforested, degraded areas)

1. Protect biodiversity, wildlife habitats, and ecosystems

2. Do not provide government subsidies for using/extracting resources

3. Require the users of public hands to reimburse Americans for use of their property

4. Hold all users of resources on public lands responsible for their environmental damage

10.2 - How Can We Manage and Sustain Grasslands?

• Reduces grass cover

• Animals can compact soil -> decreased water holding capacity -> more topsoil erosion by water and wind

• Promotes invasion of plant species that won’t be eaten

• Can cause desertification (if plants killed + soil too dry because over compaction)

• Sustaining the productivity of grasslands
• Controls the numbers and distribution of livestock
• Restores degraded grasslands

• Rotational Grazing
• Fence off damaged areas
• Cattle graze in one area, then move to the next, allowing regrowth

• Holistic Herd Management
• Short-term herd trampling aerates soil, allowing for increased nutrient cycling and soil fertility (dead grasses pushed into soil, bringing yummy nutrients)

10.3 - How Can We Sustain Terrestrial Biodiversity and Ecosystem Services?

• Establish/protect wilderness parks and other areas where humans interact with nature

• Identify and protect biological hotspots -> threatened areas of biodiversity

• Protect ecosystem services and restore damaged ecosystems

• Shift new development to degraded/cleared lands

• Increase crop productivity on existing cropland

Chapter 11 - Nonrenewable Resource Use

11.1 - What are the Earth’s Major Geological Processes and What are Mineral Resources?

• Core -> Mantle -> Asthenosphere -> crust

• Mineral Resource: concentration of 1+ minerals in earth’s crust that we can extract and process into raw materials and useful products at an affordable cost

• Sedimentary: compressed sediments, can include plant and animal remains.

• Igneous: magma cools and solidifies

• Metamorphic: other rocks changed by heat and pressure

• Erosion, Melting, Metamorphism -> Sedimentary, Igneous, Metamorphic Rocks

11.2 - How Long Might Supplies of Nonrenewable Resources Last?

• Economically Depleted: when it costs more than it is worth to find, extract, and process the remaining deposits

• High vs. Low Grade: high concentrations vs. low concentrations/densities of desired minerals.

• Geological processes determine the quantity and location of a mineral resource on the Earth.

• What Limits the Mining of Lower-Grade Ores: increased cost/energy to mine and process larger volumes of ore, availability of freshwater, environmental impact of land disruption

• Mining Tech for Ores: biomining (using GM or natural bacteria to remove desired metals from ores, leaving surrounding environment undisturbed and reducing air/water pollution BUT is very, very slow, taking decades. Only economically feasible for low-grade ores).

• To Combat Economic Depletion: recycle or reuse current supplies, waste less, use less, find a substitute, or do without.

• There’s been a sharp rise in total/per capita use of mineral resources in the U.S. since 1900, and we’ve economically depleted lead, aluminum, and iron.

• Encourage exploration for new deposits

• Stimulate development of better mining tech

• Makes it profitable to mine lower-grade ores

• Promotes conservation and theft

• Hindered by high costs, threat to marine ecosystems, and arguments over the rights to the minerals in deep ocean areas not controlled by any specific country.

11.3 - What are the Environmental Effects of Using Nonrenewable Mineral Resources?

• Types:
• Open-Pit: machines dig large pits and remove metal ores containing copper/gold/etc or sand/gravel/stone.
• Strip Mining: extracting mineral deposits that lie in large horizontal beds close to the Earth’s surface
• Area Strip Mining: used on flat terrain, huge earthmover strips overburden, power shovel removed mineral resource, and trench filled with overburden.
• Contour Strip Mining: used for extracting coal and various mineral resources on hilly, mountainous terrain, they cut a series of terraces onto the hillside, remove the overburden, extract the coal, and dump the previous overburden back onto it.
• Result: A series of spoils banks and a highly erodible hill of soil and rock (highwall)
• Strip mountaintop removal: big boom booms used to remove top of mountain to expose coal. Then, waste rock and dirt are plied into the valleys below, destroying forests, burying mountain streams, and increasing the risk of flooding.
• This also creates wastewater and toxic sludge (gooey mixture of toxic chemicals and solids removed from wastewater), which is stored in dams that can collapse.

• Effects: topsoil erosion, habitat loss, removal of vegetation and soil, increased stream turbidity, increased PM in the air

• More Expensive (higher insurance/healthcare costs for workers)

• Less Land disturbed (less than 1/10 compared to Surface Mining)

• Less Waste Material produced

• Risks: poor ventilation -> toxic gas exposure, mine shaft collapse, injury from falling rock, lung cancer, asbestos, fires, explosions, subsidence

• Rainwater leaking into abandoned mine tunnels can mix with pyrite to form sulfuric acid

• Sulfuric Acid can be carried by rainwater into streams or into groundwater

• Water pH lowers -> toxic metals (mercury, aluminum) become more soluble in water -> fish die

• Coal Mining releases Methane (has to be vented out of mine to prevent explosion + continues to seep out after mine closes) -> Greenhouse gas!

• Topsoil erosion, habitat loss, increased stream turbidity, all that fun stuff

• Soot and Particulates from mining release PM, irritating lungs.

• Large amounts of solid waste in both types of mining operations

• Filling empty mine shafts/hole

• Restoring original contours of land

• Returning topsoil, with acids/metals/tailings removed

• Replanting native plants to restore community to its near-original state

11.4 - How Can We Use Mineral Resources More Sustainably?

• Try to find Substitutes for scarce resources
• Materials Revolution
• Silicon replacing some metals for common uses
• New Technologies
• Nanotechnology, high-strength plastics
• Graphene and phosphorene
• Substitution doesn’t always work
• Platinum-industrial Catalyst

• Reduce resource Waste

• Recycle and Reuse Minerals
• Lower environmental impact than mining and processing metals from ores
• Extract valuable metals from electronic waste

• Dynamic forces that move matter within the earth and on its surface recycle the earth’s rocks, form deposits of mineral resources, and cause volcanic eruptions, earthquakes, and tsunamis.

• The available supply of a mineral resource depends on how much of it is in the earth’s crust, how fast we use it, the mining technology used to obtain it, its market prices, and the harmful environmental effects of removing and using it.

• We can use mineral resources more sustainably by trying to find substitutes for scarce resources, reducing resource waste, and reusing and recycling nonrenewable minerals.

Chapter 12 - Agriculture and Urbanization

12.1 - Why is Good Nutrition Important?

• Most hungry people live in low-income, underdeveloped countries and can only afford a low-protein, high-carb, vegetarian diet with mostly grains (living low on food chain)

• Those who are underfed/underweight or overfed/overweight face the same health risks: lower life expectancy, greater susceptibility to disease, lower productivity and quality of life

• Other things that prevent food security: war, corruption, bad weather, climate change

12.2 - How is Food Produced?

• Depend on small # of plant/animal species (14/30k edible species supply about 90% of world’s food resources). Half of the world survives on vegetarian diet (can’t afford meat)

• Food specialization violates the biodiversity principle of sustainability (depending on a variety of food sources as ecological insurance policy against changing environmental conditions)

1. Irrigation (a variety of methods that help water be supplied to crops artificially)

2. Synthetic Fertilizers (manufactured chemicals that contain nutrients like nitrogen, phosphorus, potassium, calcium, and many others)

3. Synthetic Pesticides (chemicals manufactured to kill or control populations of organisms that interfere with crop production)

• Used on 25% of all cropland, mostly in developed countries, and produces about 80% of the world’s food

• Plantation Agriculture: form of industrialized agriculture used primarily in less-developed tropical countries. It involves growing cash crops (bananas, coffee, vegetables, soybeans, sugarcane, palm oil) on large monoculture plantations, mostly for export to more developed countries.

• Traditional Subsistence Agriculture: energy from the sun + labor of humans and draft animals == enough crops for a farm family’s survival, with a little left over to sell or store as reserve

• Traditional Intensive Agriculture: farmers try to obtain higher crop yields by increasing their inputs of human/draft animal labor, animal manure for fertilizer, and water. If weather permits, they can produce enough food to feed their families and even sell for income.

• Some traditional farmers practice polyculture (growing several crops on the same plot -> relies on solar energy and natural fertilizers, and the various crops mature at different times).
• This provides food year-round and keeps the topsoil covered to reduce erosion from wind and water, while also lessening the need for fertilizer and water (root systems at diff depths capture moisture and nutrients more efficiently).
• Plus, this reduces weeds (they have trouble competing with the variety and density of crop plants) and reduces the chance of losing most or all of the crop yield to pests, bad weather, and other harmful things.
• Slash-and-burn agriculture: burning and clearing small plots in tropical forests, growing a variety of crops for a few years until the soil is depleted of nutrients, and then shifting to other plots to begin the process again.

• “USDA Certified Organic” == 100% Organic == product is produced only by organic methods and contains all organic ingredients

• “Organic” == At least 95% organic ingredients

• “Made with Organic Ingredients” == at least 70%

1. Develop and plant monocultures of selectively bred/genetically engineered high-yield varieties of key crops (rice, wheat, corn)

2. Produce high yields w/ large inputs of water, synthetic inorganic fertilizers, pesticides

3. Increase the number of crops grown per year on a plot of land

• Increased use of mechanization, GMOs, irrigation, fertilizers, and pesticides

• Benefits: greatly increases efficiency of lands, short-term profitability, food supply, decreased world hunger, increased Earth’s human carrying capacity

• Drawbacks: increased soil erosion, biodiversity loss, ground/surface water contamination

• First Green Revolution (1950-1970) dramatically raised crop yields in developed countries (U.S)

• Second Green Revolution (1967) saw middle-income, less developed countries (ex: India, China, Brazil) get fast growing varieties of rice and wheat specifically for tropical/subtropical climates

• Increases reliance on fossil fields, contributing to climate change

• Heavy machinery compacts soil, decreasing H2O holding capacity and making topsoil more prone to erosion

• Increased yield and food stability in regions prone to famine (India, Pakistan, Mexico)

• Since 1974, global meat consumption has doubled (1: pork, 2: poultry, 3: beef), and it’s likely to double again by 2050 as incomes rise

• Half of the world’s meat comes from livestock grazing on grass in unfenced rangelands and enclosed pastures.

• The other half is grown in feedlots or CAFOs (Concentrated Animal Feeding Operations -> Factory Farms) where animals are fed grain, soybeans, fishmeal, or fish oil, lace with growth hormones and antibiotics to accelerate livestock growth.

• Methods used: global satellite positioning equipment, sonar fish-finding devices, huge nets, long fishing lines, spotter planes, refrigerated factory ships

• Fish/Shellfish are also produced through aquaculture (fish farming): raising fish in freshwater ponds, lakes, reservoirs, and rice paddies and in underwater cages in coastal/deeper ocean waters
• Amount produced through aquacultures grew 12x since 1980
• Most involve raising species that feed on algae and other plants, but the farming of meat-eating species of fish is rising rapidly (shrimp, salmon) in developed countries.

• 57% of oceans are being harvested at full capacity, and 30% are being overfished. Overfishing -> threatens food security for the 3 billion people who depend on fish for at least 20% of their animal protein

• It takes about 10 units of fossil fuel energy for 1 unit of food energy on the tableFishing fleets use 12.5 units of energy for 1 unit of food energy from seafood on the table (large net energy loss)

• Takes much less time than traditional crossbreeding, costs less, and allows the insertion of a gene from any other organism, not just the same species.

• Benefits:
• May need less fertilizer, pesticides, and water
• Can be resistant to insects, disease, frost, drought
• Can grow faster and raise yields
• May tolerate more herbicide levels
• Longer shelf life

• Drawbacks:
• Unpredictable genetic/ecological effects
• May put toxins in food
• Copd repel or harm pollinators
• Could promote pesticide-resistant insects, herbicide resistant weeds, and plant diseases
• Could disrupt seed market and reduce biodiversity

12.3 - What are the Environmental Effects of Environmental Food Production?

• Converts grasslands, forests, and wetlands to crops or rangeland (60% of the world’s ice-free land)

• Fish die from pesticide runoff

• Wild predators are killed to protect livestock

• Agrobiodiversity (the genetic variety of animal/plant species used on plants to produce food) is lost in place of monoculture strains
• Approx. 75% of the genetic diversity of agricultural crops has been lost since 1900. About 97% of the food plant varieties available to farmers in the U.S. 1940s no longer exist
• Losing agrobiodiversity -> shrinking of the world’s genetic “library” of plant varieties -> can decrease food yields -> violates biodiversity principle of sustainability

• Erosion (movement of soil components, especially surface litter and topsoil, because of water and wind actions).
• Three types of flowing water erosion: sheet erosion (on level land, removes thin sheets of topsoil), rill erosion (tiny streams/rivulets of water that carve small channels/rolls into topsoil), gully erosion (larger streams of water removing enough soil to create gullies)
• Wind erosion loosens and blows topsoil particles away, especially in dry areas with relatively flat land not covered by vegetation
• Undisturbed, vegetated ecosystems are able to reduce erosion through the roots of plants anchoring topsoil. But when this vegetation is removed through farming, deforestation, overgrazing, and other human activities, it can erode much faster. On ⅓ of the world’s cropland, topsoil is eroding faster than it forms.
• Major Harmful Effects: Loss of soil fertility through depletion of plant nutrients, water pollution in surface waters that can cause eutrophication by overloading the water with plant nutrients, and release of carbon stored in the soil contributing to climate change

• loss of fertility, salinization, waterlogging, desertification (when the productive potential of topsoil falls by 10% or more because of a prolonged drought + human activities that expose topsoil to erosion)
• Desertification can be moderate to severe, and can even expand existing deserts/create new ones. The natural process of desertification has been exacerbated by human activities by excessive plowing, overgrazing, and deforestation

• Excessive Irrigation can Pollute Soil/Water
• Accounts for 70% of the water used by humanity. 16% of irrigated cropland accounts for 44% of the world’s food.
• Most irrigation water is a dilute solution of various salts (NaCl) picked up as the water flows over soil and rocks. Irrigation water that isn’t absorbed evaporates, leaving a thin crust o f dissolved mineral salts in the topsoil. Repeated irrigation water evaporation in dry climates -> accumulation of salts in the upper soil layers -> soil salinization
• Stunts crop growth, lowers crop yields, can kill plants and ruin the land
• Also, waterlogging (water accumulates underground and gradually raises the water table, lowering the productivity of crop plants and kills them after prolonged exposure because it deprives plants of oxygen. Caused by excessive irrigation water added in attempts to reduce salinization)
• It’s mostly just depleted our water supply.

• Accounts for 70% of the freshwater removed from aquifers and surface waters worldwide.

• Produces 60% of all water pollution

• Increased runoff, sediment pollution, and flooding from cleared land, as well as pollution from pesticides

• Algal blooms caused by runoff of fertilizers and farm wastes kills marine life/ecosystem

• Over Fertilizing fields leads to excess fertilizer runoff, contributing to eutrophication + nitrates percolating down through the soil where they contaminate groundwater

• Emits 25% of the world’s greenhouse gas emissions (CO2 from fossil fuels, N2O from inorganic fertilizer use, CH4 from cattle)

• Nitrates in drinking water causing blue baby

• Pesticide residues in water/food/air

• Livestock wastes in drinking and swimming water

• Bacterial contamination of meat

• Large inputs of water/synthetic inorganic fertilizers and pesticide needed for green revolution/ genetically modified crop varieties to produce higher yields than traditional strains. Plus, they cost too much for subsistence farmers in less-developed countries

• There’s a point where yields won’t increase because of the inability of crop plants to take up nutrients from additional fertilizer/irrigation water

• Population growth, limited availability of irrigation water, soil salinization, and lack of money among the world’s conventional farmers prevent the expansion of irrigation for cropland

• Climate change, melting mountain glaciers, rising sea levels flooding croplands, longer and more intense droughts

• We could use more land, but massive clearing of forests would decrease biodiversity, speed up climate change, and increase soil erosion. Plus, they have terrible soil fertility and steep slopes and are expensive to clear.

• feedlots/CAFOs produce widespread harmful health/environmental effects. Plus, the meat produced is cheap but doesn’t include the harmful environmental and health costs (violates full-cost principle). They also don’t use much land, reduce overgrazing, reduce soil erosion, and protect biodiversity. But there’s SO MANY NEGATIVES.
• HUGE amounts of water used to irrigate the grain crops that fed the livestock (1700 liters of water per quarter-pound hamburger -> more water than it takes to raise the same quantities of pork, chicken, eggs, and milk combined).
• Inefficient use of irrigation water + depletes groundwater supplies + using it to wash away livestock wastes leads to most of it flowing into streams and other waterways, polluting those aquatic ecosystems
• Manure from CAFOs should be returned to the soil (chemical cycling principle of sustainability), but its not, and is often contaminated with residues of antibiotics and pesticides that makes it unfit for fertilizing use
• Odor problems + large quantities of greenhouse gases emitted from CAFO animal waste
• Large amounts of energy used (mostly from oil) AND cows release lots of methane (25x the warming potential of CO2 per molecule) -> industrialized livestock production generates 18% of the world’s greenhouse gases, more than all the world’s vehicles combined.
• Antibiotic use in these facilities plays a role in the rise of genetic resistance among many disease-causing bacteria, resulting in new, more genetically resistant infectious disease organisms, some of which can infect humans

• ⅓ of the wild fish caught from the oceans are used to make the fishmeal/fish oil that is fed to farmed fish and livestock, depleting many populations of fish crucial to marine food webs. Aquaculture uses 70$ of all fishmeal and 90% of all fish oil which is BAD.
• Ex: Some countries are using tons of Krill from Antarctic waters. These krill are the base of the antarctic food web, and thus, all species, including endangered penguins and whales, depend on them

• PCBs and Dioxins (75 chlorinated hydrocarbon compounds formed as unwanted byproducts) contaminate some of the fishmeal/fish oil, contaminating farm-raised fish and people who eat them. Plus, some fish farms that raise carnivorous fish have large amounts of polluting waste.

• Use of pesticides/antibiotics on fish farms pollutes too. Some farmed species (shrimp, tilapia, salmon, trout) have 5 diff antibiotics, which can lead to microbial resistance which is bAD

• It can also degrate aquatic ecosystems (especially mangrove forests, which have been cleared for shrimp farms -> loss of biodiversity and valuable ecosystem services)

12.4 - How can we Protect Crops from Pests more Sustainably?

• Biopesticides (chemicals that plants have been historically using to ward off, deceive, or poison the pests that feed on them) were the first generation pesticides that we began harnessing.

• DDT (dichlorodiphenyl- trichloroethane): first of the second-generation pesticides that became the world’s most used pesticide. However, some of these second-gen pesticides, including DDT, have turned out to be hazardous for birds, wildlife, and even humans (Rachel Carson’s “Silent Spring” led to a reduction in DDT usage)

• Advantages:
• Human lives saved from malaria
• Increased food supplies and reduced food losses
• Helps control erosion and build soil fertility by avoiding plowing
• Helps farmers reduce costs and raise profits

• Disadvantages:
• Accelerates development of genetic resistance in pests, rendering it ineffective after a while (1942 - 1947: crop losses from insects increased from 7-13% even with 10x increase in pesticide use)
• Genetic biodiversity gives some pests resistance to pesticide, and pesticide artificially selects for the pests that have this resistance. Over time, only the resistant pests remain and reproduce.
• Expensive for farmers
• Some insecticides (broad-spectrum agents) kill natural predators of the pests (natural enemies). Narrow-spectrum, or selective agents, are effective against a narrow range of organisms.
• Causes environmental pollution/ harms some wildlife and even people

• U.S Federal Agencies and their laws
• EPA, USDA, FDA
• Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), 1947 (used to ban or severely restrict to use of many chlorinated hydrocarbon insecticides (organic compound made up of atoms of carbon, hydrogen, and chlorine)
• Food Quality Protection Act, 1996 (required EPA to reduce the allowed levels of pesticide residues in food by a factor of 10 when there’s inadequate information on its effects on children)

• These laws, however, are often inadequate and poorly enforced. Plus, the U.S. exports many banned pesticides, and through the circle of poison effect, pesticides banned in one country but exported to others can return to the host country through residues on imported food

• Biological Control: natural predators, parasites, disease-causing bacteria/viruses, sex attractants and hormones to control the developmental processes of pests/lure them into traps
• Benefits: usually nontoxic to other species and less costly than pesticides
• Drawbacks: difficult to mass produce, slower and more difficult to apply, can become pests themselves

• Ecological Controls: using polyculture/plant diversity to provide habitats for the natural enemies of pest species

• Cultivation Controls: planting different crops from year to year and adjusting planting times to starve pests

• Genetic Engineering: speeding up development of pest and disease-resistant crop strains
• GMOs: gene for pest resistant trait is added to the plant through genetic modification (ex: BT corn that produces Bt crystals toxic to pests -> has decreased insecticide use, since corn makes its own insecticide) (ex: Roundup Ready crops made resistant to broad herbicide -> has increased herbicide use because crops can’t be harmed by it)
• Benefits: may require less fertilizer, pesticides, and water, may have longer shelf life, may grow faster and increase yields, could improve food security
• Drawbacks: little information about long-term health effects, could promote pesticide-resistant insects or herbicide-resistant weeds, potential environmental effects of GM-populations in the wild

• Integrated Pest Management: A combination of methods used to effectively control pest species while minimizing the disruption to the environment/pesticide usage.
• Researching and monitoring pests and targeting methods to specific pest life cycles
• Biocontrol: bringing in a natural predator/parasite/competitor to control the pest, including purchasing and spreading the control organisms in fields or building homes for them to attract them naturally
• Crop Rotation: prevents pests from becoming established by disrupting their preferred food choice (many pests prefer one specific crop, laying eggs in the soil so their babies can eat the crop) + disrupting weed growth by preventing bare soil from being taken over by weeds (different crops can be planted at different times)
• Intercropping: growing 2+ crops in the same proximity, using resources more efficiently than single crops (more yields and profit). These mixtures have lower pest densities because the mixture confuses the insects and attracts beneficial predators. It also allows for more effective management of cover crops.
• Benefits:
• Reduces death/mutation of non-target species
• Reduces effects on human consumers of produce
• Reduces contamination of surface and ground water by agricultural runoff w/ pesticides
• Drawbacks:
• Can be more time consuming and costly than just crop dusting pesticides

12.5 - How can we use Freshwater more Sustainably?

1. Low costs of freshwater due to government subsidies (violates the full-cost principle of sustainability) gives little incentive to invest in water-saving technologies
1. Higher prices encourage water conservation BUT makes it difficult for low-income farmers and city dwellers to meet their needs. Lifeline rates (set amount of free/low priced water, and then gradually increasing cost of water as water use increases) helps with this problem

2. Lack of government subsidies for improving water use efficiency
1. Farmers that receive subsidies to keep water prices low have vigorously opposed efforts to eliminate or reduce them.

• Only about 60% of the world’s irrigation water reaches crops -> most irrigation systems are highly inefficient

• Industrial (power plants, metal and plastic manufacturing)

• Municipal (households - toilet, shower, laundry, drinking water, cooking)

• Agricultural (water for livestock, irrigation for crops)

• Saltwater Intrusion: excessive pumping near the coast lowers the water table’s pressure, allowing saltwater to seep into groundwater and contributing to the salinization of crops

• Cone of Depression: forms when water table is lowered by excessive pumpkin, depleting water and drying nearby wells while also contributing to subsidence

• Flood Irrigation: flooding a field with water
• Benefits: inexpensive, easier to do
• Drawbacks: 50-80% efficient, with 20-50% of water lost to evaporation and runoff. Waterlogged soil is disruptive to some plants (too much water is left to sit in the soil -> water table raised, inhibits plants’ ability to absorb gases through their roots)

• Furrow Irrigation: cutting furrows between crop rows and filling them with water
• Benefits: inexpensive, easy
• Drawbacks: 66% efficient with 33% of water lost to evaporation or runoff

• Spray Irrigation: pumps ground water into spray nozzles across an agricultural field
• Benefits: more efficient than flood and furrow irrigation -> 75% efficiency with less than 25% of water lost to evaporation or runoff
• Drawbacks: more expensive, requires energy to run
• Center-Pivot, low-pressure sprinkler, which uses pumps to spray water on a crop, allows 80% of water to reach crops. Low-energy, precision application (LEPA) sprinklers, another form of center-pivot irrigation, have 90-95% efficiency.

• Drip Irrigation: uses perforated hoses to release small amounts of water to roots
• Benefits: 95% efficient, with approx 5% of water lost to evaporation and runoff
• Drawbacks: expensive, so not often used

• Hydroponics: not really irrigation, but there’s no soil, bathed in H2O with nutrients, little to no pesticide use, water can be tested and recycled, roots are supported, and can be vertical and indoors.

• Solutions: drip irrigation, soil aeration, flushing with fresh water, switching to freshwater source

• Desalinization: removing dissolved salts from ocean water or brackish (slightly salty). Helps to increase supplies of freshwater.
• Distillation: heating saltwater until it evaporates, leaving behind salts in solid form, and condenses as freshwater
• Reverse Osmosis/Microfiltration: high pressure to force saltwater through a membrane filter with pores small enough to remove the salt and other impurities
• Drawbacks: high cost, requires many chemicals that sterilize the water and keep algae growth to a minimum but kill many marine organisms and require lots of money, and produces lots of salty wastewater that must be disposed of

• Also, Rainwater Harvesting (using pipes from rooftops and channels in the ground to direct water to underground/aboveground storage tanks (cisterns), ponds, and plastic barrels for use during dry seasons

• Also, polyculture (for more canopy cover and to reduce evaporative water losses), planting deep-rooted perennial crop varieties (plants that can live for 2+ years), controlling weeds, and mulching fields used to increase the amount of crop per drop of rainfall.

• Don’t use thirsty crops in dry areas

• Import water intensive crops and meat rather than cultivating them

• Encourage organic farming and polyculture to retain soil moisture

• Monitor soil moisture to add water only when necessary

• Expand drip irrigation/other efficient irrigation methods

• Irrigate at night to reduce evaporation

• Line canals that bring water to irrigation ditches

• Irrigate with treated wastewater

• Redesign manufacturing processes to use less water

• Recycle water in industry

• Fix water leaks

• Landscape yards with plants that require little water

• Use drip irrigation often

• Use water=saving shower heads, faucets, appliances, and toilets (or waterless composting toilets)

• College and reuse gray water in/around houses, apartments, office buildings

• Raise water prices, use meters

• Use water-saving toilets, showerheads, faucets

• Take short showers and not baths

• Turn off sink faucets when not in use

• Wash only full loads of clothes or use the lowest possible water-level setting

• Repair water leaks

12.6 - How can we reduce the threat of Flooding?

• Fertile soil on flat land suitable for crops, ample freshwater for irrigation, availability of nearby rivers for transportation and recreation

1. Removal of Water-Absorbing Vegetation: removing trees on on a hillside for timber/livestock/fuelwood allows freshwater to rush down the slopes, eroding precious topsoil while increasing flooding and pollution in local streams + clearing trees makes landslides and mudflows more likely

2. Draining of Wetlands that naturally absorb floodwaters: these areas are then covered with pavement and buildings that greatly increase runoff, contributing to increased flooding and pollution of surface waters.

3. Rise in Sea Levels: contributes to flooding of coastal cities in the near future

• Preserve forests in watersheds

• Preserve and restore wetlands on floodplains

• Tax development on floodplains

• Increase use of plains for sustainable agriculture and forestry

• Rely more on nature’s systems (wetlands - naturally absorb excess water and release it back slowly)

• Rely less on engineering devices (dams, levees, channelized streams)

• Don't build in areas that are subject to frequent flooding

• Strengthen and deepen streams (channelization)

• Building levees or floodwalls along streams (however, levees can make floods worse sometimes. Be careful.)

• Build dams

12.7 - How can we produce Food more Sustainably?

1. Conserve Topsoil
1. Soil Conservation: using various methods to reduce topsoil erosion and restore soil fertility, mostly by keeping the land covered with vegetation.
1. Terracing: converting steeply sloped land into a series of broad, nearly level terraces that run across the land’s contours, retaining water for crops while reducing topsoil erosion by controlling runoff
2. Contour Planting: plowing and planting crops in rows across the slope of the land rather than up and down, with each row being a small dam that helps hold topsoil by slowing runoff
3. Strip Cropping: alternating rows of a row crop and a cover crop (completely covers the soil -> traps topsoil that erodes from the row crop and catches/reduces runoff)
4. Alley Cropping/Agroforestry: crops that add nitrogen to the soil (legumes) are planted together in alleys between orchard trees/fruit-bearing shrubs that provide them shade, helping reduce water loss by evaporation and helps retain/slowly release moisture
5. Windbreaks (shelterbelts): planting trees around crop fields to reduce wind erosion, retain soil moisture, supply food for fuel, and provide habitats for birds/insects that control pests and pollinate.
6. No-till / conservation-tillage farming: Eliminate/Minimizing Plowing/tilling of topsoil, leaving crop residues on the ground. This increases crop yields and reduces soil erosion/water pollution from sediment and fertilizer runoff, but it involve greater use of herbicides. And we all know the dangers of herbicides.
7. Hydroponics: growing the plants without soil.
8. Using Perennial Crops: living for 2+ years, they can be harvested multiple times, with longer, more established roots and prevention of bare soil between harvests.

2. Restore Soil Fertility: restores nutrient levels in the soil
1. Crop Rotation: replanting the same crops continuously depletes the soil of the same nutrients, and crop rotation can allow the soil to recover from nitrogen-demanding crops (corn). For example, planting peas/beans (legumes -> have nitrogen fixing bacteria in their root nodules) helps return nitrogen to the soil
2. Limestone: releases calcium carbonate (base), neutralizing acidic soil
1. Acidic soil has a high H+ ion concentration, displacing positively charged nutrients from the soil (leeching them out). Acidic soil also makes toxic metals more soluble in soil (ex: aluminum)
2. Calcium is a necessary plant nutrient as well
3. Organic Fertilizer: derived from plant/animal materials or synthetic inorganic fertilizer made of inorganic compounds containing many nutrients.
1. Animal manure (dung/urine of cattle, horses, poultry, and other farm animals. Helps improve topsoil structure, adds organic nitrogen, and stimulates the growth of beneficial soil bacteria and fungi)
2. Green manure: leftover plant matter from a cover crop (crop planted in the offseason, between harvest and replanting of the main crop)
1. Cover crop roots stabilize soil limiting topsoil erosion
2. The remains of cover crops (green manure) left on the field break down to release nutrients back into the soil
3. Compost (when microorganisms break down organic matter in the presence of oxygen)
4. Rotational Grazing: regular rotation of livestock to different pastures to prevent overgrazing
1. Overgrazing kills plants, compacts and erodes soil.
2. Rotational grazing can actually promote pasture growth at a faster than normal rate
3. Clips grass back to length where growth is fastest, encouraging deeper root growth

3. Reduce Soil Salinization and Desertification
1. To Prevent:
1. Reduce irrigation
2. Use more efficient irrigation methods
3. Switch to salt-tolerant crops
2. To Clean Up:
1. Flush soil (expensive and inefficient)
2. Stop growing crops for 2-5 years
3. Install underground drainage systems
3. Other Stuff:
1. We can’t control the timing/location of droughts
2. But we can reduce population growth, overgrazing, deforestation, and destructive forms of planting/irrigation.
3. We can also decrease human contribution to climate change.
4. We can also plant trees and other plants that anchor topsoil and hold water, as well as growing trees and crops together + establish windbreaks.

4. Produce and Consume Meat/Dairy Products More Sustainably
1. Meat consumption is the largest contributor to the ecological footprints of individuals in affluent nations
2. Some Meats are More Efficient than others. For every 1000 calories of meat for human consumption:
1. Beef - 36,200 calories
2. Pork: 11,300 calories
3. Poultry: 8800 calories
4. Eggs: 6300 calories
5. Dairy: 5900 calories
3. Insects are a good form of protein, as well as fiber, healthy fats, and vital micronutrients (calcium, iron, B vitamins, zinc)
4. Add meatless days to our week + eliminate meat from our diets and switch to a vegetarian diet of protein-rich plant foods! delicious!

5. Managing and Sustaining Fisheries
1. Fishery Regulations
1. Set low catch limits
2. Improve monitoring and enforcement
2. Economic Approaches
1. reduce/eliminate fishing subsidies
2. Certify sustainable fisheries
3. Protection
1. Establish no-fishing areas
2. Establish more marine protected areas
4. Consumer Information
1. Label sustainably harvested fish
2. Publicize overfished and threatened species
5. Bycatch
1. Use nets that allow escape of smaller fish
2. Use net escape devices for seabirds and sea turtles
6. Aquaculture
1. Restrict locations of fish farms
2. Improve pollution control
7. Nonnative Invasions
1. kill/filter organisms from ship ballast water
2. Clean aquatic recreation gear

6. Practice More SUstainable Aquaculture
1. Open-Ocean Aquaculture: raising large carnivorous fish in large underwater pens located far offshore
2. Recirculating Aquaculture Systems: water used to raise fish is continuously recycled, converted to fertilizer, and used to grow other stuff, eliminating fish waste pollution of aquatic systems and reduces need for antibiotics and other chemicals to combat diseases among farmed fish + reduces problem of farmed fish escaping
3. Polyaquaculture: raising fish/shrimp with algae, seaweeds, and shellfish in coastal lagoons/ponds/tanks, applying the chemical cycling/biodiversity principles of sustainability
4. Consumers choosing fish species that eat algae and other vegetation rather than fish oil/fishmeal produced from other fish, because raising carnivorous fishes contributes to overfishing, population crashes, and is altogether unsustainable

7. Expand Organic Agriculture
1. Builds soil organic matter
2. Reduces erosion and water pollution
3. Uses less fossil fuel energy
4. Cuts greenhouse gas emissions
5. Organic yields == conventional yields
6. More weed tolerant
7. Compare favorably in years of drought
8. Can be more profitable
9. Consumers reduce exposure to pesticide residues and to bacteria-resistant antibiotics
10. Requires more human labor!!

8. Shift to more Sustainably Food Production
1. More of:
1. High-yield polyculture
2. Organic fertilizers
3. Biological pest control
4. Integrated pest management
5. Efficient irrigation
6. Perennial crops
7. Crop rotation
8. Water-efficient crops
9. Soil conservation
10. Subsidies for sustainable farming
2. Less of:
1. Soil erosion
2. Soil salinization
3. Water pollution
4. Aquifer depletion
5. Overgrazing
6. Overfishing
7. Loss of biodiversity/agrobiodiversity
8. Fossil fuel use
9. Greenhouse gas emissions
10. Subsidies for unsustainable farming

12.8 - How can we Improve Food Security?

• Reducing poverty and chronic malnutrition

• Producing food sustainably

• Relying on locally grown food (CSA - community supported agriculture)

• Cutting food waste in restaurants, homes, and supermarkets

• Government policies to improve food production and security
• Controlled food prices: Placing legally mandated upper limit on prices to keep them artificially low
• Helps consumers, makes it harder for farmers to make a living
• Provided subsidies: price supports, tax breaks, and other financial support
• helps farmers stay in business and encourages increased food production
• Low-interest loans
• Immunization and vitamins

12.9 - How can Cities become more Sustainable and Livable?

• The percentage of the global population that lives in urban areas has grown sharply, and this trend is projected to continue

• The numbers/sizes of urban areas are increasing! (30 megacities in 2015)

• Poverty is becoming increasingly urbanized, mostly in less-developed countries

1. People migrated from rural areas to large central cities (jobs, entertainment, cultural attractions)

2. From these large central cities, people went to nearby smaller cities and suburbs

3. Then, people went from the North/east to the South/West

• Replaces soil, vegetation, wetlands, etc. with impervious (water can’t penetrate) surfaces, like cement, concrete, or asphalt
• Prevents water infiltration and groundwater recharge
• Water will runoff into local bodies

• CO2 Emits from:
• Cement production
• Construction machinery
• Deforestation (less carbon sequestration and decomposition of cut trees)
• Landfills for trash from large populations

• In Coastal Cities: population growth can lead to saltwater intrusion b/c of sea level rise and excessive groundwater withdrawal

• Centers of economic development, innovation, education, technological advances, social/cultural diversity, and jobs

• Better healthcare/family planning/educational/social service access

• Recycling more feasible, occupy less land, reduces stress on wildlife habitats outside of urban areas, less driving (more mass transportation, carpooling, walking, biking)

• Unsustainable; consume 75% of world’s resources and produce 75% of world’s pollution -> huge ecological footprints that make them unsustainable

• Lack vegetation, can suffer from flooding, concentrate pollution and health problems, excessive noise

• Lots of heat generated by cars/factories/lights/ACs/dark roofs/streets that create an urban heat island surrounded by cooler suburban and rural areas

• Causes of Urban Sprawl:
• Cheaper property in suburbs than cities (larger properties for same price)
• Cars make it easy to get from suburbs to city
• Domino effect (neighbors leave, you leave too)
• Fewer residents in cities -> decline in city tax revenue -> living in city is worse, because theres a decrease in city services
• Residents leave, so businesses follow
• Abandoned homes + businesses create blight (unsightly, rundown infrastructure), making more people leave
• Expanded highway system makes travel easier and increases driving
• Increase in driving == more fuel tax revenue, used to build more highways
• Highway expansion == easier to commute from suburbs into urban areas

• Undesirable Impacts:
• Land and Biodiversity
• Loss of cropland
• Loss and fragmentation of forests, grasslands, wetlands, and wildlife habitat
• Water
• Increased use and pollution of surface water and groundwater
• Increased runoff and flooding
• Energy, Air, and Climate
• Increased energy use and waste
• Increased emissions of carbon dioxide and other air pollutants
• Economic Effects
• Decline of downtown business districts
• More unemployment in central cities

1. Bicycles
1. Advantages:
1. Quiet, non polluting
2. Requires few resources to manufacture and maintain (low cost)
3. Burns no fossil fuels
4. Requires little parking space
2. Disadvantages:
1. Little protection in an accident
2. No protection against weather and environment
3. Impractical for long trips
4. Bike lanes/secure bike storage not widespread

2. Bus Rapid-Transit (BRT) /Conventional Bus Systems
1. Advantages:
1. Reduces car use and air pollution + congestion of traffic
2. Can be rerouted as needed
3. Cheaper than heavy-rail system
2. Disadvantages:
1. Can lose money (require affordable fares)
2. Can get caught in traffic, adding to noise and pollution
3. Commit riders to transportation schedules

3. Mass Transit Rail
1. Advantages:
1. Uses less energy/produces less air pollution than cars
2. Uses less land than roads/parking lots do
3. Causes fewer injuries and deaths than cars
2. Disadvantages:
1. Expensive to build and maintain
2. Cost-effective only in densely populated areas
3. Commits riders to transportation schedules

4. Rapid Rail
1. Advantages:
1. Much more energy efficient per rider than cars/planes
2. Produces less air pollution than cars/planes
3. Can reduce need for air/car travel, roads, and parking areas
2. Disadvantages:
1. Costly to run and maintain
2. Causes noise and vibration for nearby residents
3. 4dAdds risk of collision at car crossings

• 15 Minute City: a city with public transport and a walkable city design that attracts residents to stay
• Mixed land use: residential, business, entertainment buildings all located in the same area of a city
• Enables walkability and sense of place

• Zoning is the most common (areas of land are designated for certain uses - residential, commercial, or mixed)
• Pros: can be used to control growth and to protect areas from certain types of development
• Drawbacks:
• can threaten or destroy wetlands, prime cropland, forested areas, and open space
• Often favors high-priced housing, factories, hotels, and other business over protecting environmentally sensitive areas/providing low-cost housing (most governments depend on property taxes)
• Overly strict zoning == less innovative approaches to solve urban problems

• Limits and Regulations
• Limit building permits
• Draw urban growth boundaries
• Create greenbelt around cities

• Zoning
• Promote mixed use of housing and small businesses
• Concentrate development along mass transportation routes

• Planning
• Ecological land-use planning
• Environmental impact analysis
• Integrated regional planning

• Protection
• Preserve and buy new open space
• Prohibit certain types of development

• Taxes
• Tax land, not buildings, on its actual use instead of highest value as developed land
• Provide tax breaks for agreeing not to allow certain types of development on land, and for cleaning up/developing abandoned urban cities

• Revitalization and New Growth
• Revitalize existing towns/cities by building well-planned new towns and villages within cities

• Abandoned lots/industrial sites are cleaned up and used, nearby forests/grasslands/farms are preserved, food comes from nearby organic farms/solar greenhouses/community gardens, and parks are readily available.

• Salt (plant/insect death through salinization)

• Sediment (contributes to turbidity)

• Fertilizer (eutrophication)

• Pesticides (kills non-target species -> loss of species diversity)

• oil/gasoline (suffocates fish/kill aquatic insects and creatures)

1. Permeable (Pervious) Pavement
1. Specifically designed to allow stormwater to infiltrate and recharge groundwater
2. Decreases runoff, decreasing pollutants carried into storm drains and into local surface water
3. Decreases likelihood of flooding during heavy rainfall
4. Drawbacks: more costly than traditional pavement

2. Rain Garden
1. Decrease runoff by allowing it to soak into garden soil surrounding storm drain
2. Decreases likelihood of flooding during heavy rainfall
3. Creates habitat for pollinators, sense of place and stores CO2

3. Build Up, Not out
1. Building vertically decreases impervious surfaces, decreasing urban runoff
2. Can combine “green roof” or rooftop gardens to further decrease runoff
1. Green roof also sequesters CO2 and filters air pollutants out
2. Plants absorb NO2, PM, and other pollutants into stomata and store in tissue or soil

4. Public Transit
1. More cars on road == more pollutants on streets to runoff into storm drains and local waters (motor oil, tire pieces, gasoline, antifreeze)
2. More cars == more lanes and parking lots (impervious surfaces) and more stormwater runoff
3. Public transit == less urban runoff, less pollutants, less CO2 emissions from cars on the road, and less traffic overall. So nice.

Chapter 13 - Nonrenewable Energy

13.1 - What Types of Energy Resources Do We Use?

• Fossil Fuels: fossilized remains of ancient biomass, takes millions of years to form (coal, oil, natural gas)
• Most Common Fuel source Globally:
• Oil -> Gasoline == fuel for vehicles
• Coal == primary fuel for electricity generation
• Natural Gas == secondary fuel for electricity generation, primary fuel for heating
• Non Renewable and will eventually be depleted but short term economic profit drives extraction and use (discovered but unharvested reserves represent economic benefit to countries)
• Tar/Oil Sands: bitumen deposits where crude oil can be recovered but with higher water and energy inputs
• This extends the world’s supply of crude oil

• Nuclear: energy generated from uranium or other radioactive fuels
• Third largest source of energy: uranium fission -> heat to turn water into steam -> turns turbine to generate electricity

• Depletable Renewables: can run out if overused (biomass -> wood, charcoal, ethanol)

• Nondepletable Renewables: don’t run out at all (solar, wind, hydroelectric, geothermal)
• Hydroelectric energy (Dams) are 2nd largest source: water spins turbine to generate electricity

• Avg U.S. resident uses 5x as much energy as the world average

• Still industrializing, population still growing rapidly -> energy will also increase on a per-person basis as their economies industrialize and residents achieve higher standards of living

• Many rely on subsistence fuels (biomass that is easy to gather and/or purchase; can drive deforestation)

• Economic Development -> affluence -> higher GDP per capita -> higher energy use

• As developing nations develop, fossil fuel consumption will increase: Oil for gasoline, Coal/Natural gas for electricity (more demand for electricity as homes and manufacturing increase)

• Availability: fossil fuel use depends on discovered reserves and the accessibility of them

• Price: fossil fuel prices fluctuate dramatically as new reserves are discovered and existing reserves are depleted
• Fracking (blasting fluid deep below the earth's surface to crack sedimentary rock formations, like shale, sandstone, limestone, etc) opens new NG reserves, increasing availability and decreasing price -> more use

• Government Regulation: can mandate certain energy source (ex: 25% renewable by 2025)
• The government CANNOT directly raise/lower prices of energy sources
• The government CAN:
• Issue tax increases to discourage companies from building fossil fuel plants
• Issue rebates (tax credits) to encourage development of renewable energy

• Geological Features: shale formations, sandstone beds, coal seams, limestone

• Each step in making energy available requires high-quality energy (ex: oil must be found, pumped, transferred to refinery, converted to gasoline, and delivered to consumers)

• Wood/Charcoal most common in developing nations: wood is free, cheap to cut down and use as fuel; can cause deforestation and habitat loss. Charcoal is made by heating wood under low oxygen for a while

• Peat: partially decomposed organic matter found in wet, acidic ecosystems (bogs, moors). Can be dried and used as biomass fuel source

• Combustion is a step in the carbon cycle;, as hydrocarbons are burned to release energy, the carbon stored in them reacts with O2 in the air to form CO2.

• #1 Source is Coal, #2 is natural gas

• Hydrocarbons/Fossil Fuels include: Methane, Gasoline, propane, butane, coal
• Wood/Biomass work the same way; they are burned to release heat and CO2.

• Coal is 30% efficient in this process (30% of energy from the bonds in the hydrocarbons are converted to electricity)

• Natural Gas is 60% efficient -> energy “lost” or not converted escapes as heat

• Cogeneration: the heat produced from electricity generation is used to provide heat (air/hot water) to a building. CHP (combined heat and power) systems are close to 90% efficient.

13.2 - What Are the Advantages and Disadvantages of Using Oil?

• Formed By: decayed remains of ancient microorganisms compacted beneath layers of rock and subjected to high pressures and temperatures over millions of years

• Landscapes surveyed -> seismic survey of rock formations -> 3D Seismic maps show locations/sizes of underground rock formations, including those containing oil -> drill exploratory well -> if profitably, a well is drilled and oil flows to bottom, where it’s pumped to the surface

• Peak Production: the point in time when the pressure in an oil well/all oil wells in a nation drops and its rate of conventional crude oil production starts declining. Usually occurs after a decade.

• Pumped out -> transported to refinery by truck/pipeline/rail/ship -> heated in pressurized vessels to separate it into various fuels and other components (refining -> requires high quality energy input, decreases net energy of oil)
• Petrochemicals: approx. 2% of the products of refining, they’re used as raw materials to make industrial organic chemicals, cleaning fluids, pesticides, plastics, synthetic fibers, paints, medicines, etc.

• Crude oil is trapped UNDER rocks.

• Largest Proven Reserves: Venezuela, Saudi Arabia, Canada

• The US has had to import most of its oil, but thanks to oil produced from shale rock, we’ve been able to rely less and less on suppliers (Canada, Saudi Arabia, Venezuela, Mexico, Colombia)

• However, oil produced from shale rock is likely to get depleted by 2020.

• Big Issues: US uses 20% of world’s oil prod, produces 13%, has only 3.2% of reserves

• Ample supply for several decades

• Net Energy is Medium (but decreasing)

• Low Land Disruption

• Efficient distribution System

• Water pollution from oil spills and leaks

• Environmental costs not included in market price

• Releases CO2 and other air pollutants when burned

• Vulnerable to international supply interruptions

• Oil produced from shale rock is named shale oil. It’s dispersed within bodies of shale rock compared to conventional oil trapped between layers.
• Mining, crushing, heating oil shale rock -> extracting kerogen (mixture of hydrocarbons that can be distilled to produce shale oil) -> must be heated to increase flow rate -> processed to remove impurities -> reduced net energy
• 72% of shale rock reserves are buried in US government-owned land in Colorado, Wyoming, and Utah. Lots of supply, low net energy + harmful environmental impact (rock waste, possible kerogen leaks, wastewater, high water use)

• Oil Sands/Tar Sands: mixture of clay/sand/water/organic material named bitumen (thick sticky, tar-like heavy oil with high sulfur content). Most are in Canada, some in the US too.
• Drill vertical wells -> pump steam to melt bitumen embedded in sand -> pump to surface in order to convert to heavy synthetic oil
• Requires clear cutting forests, strip mining the land -> produces large amounts of natural gas to heat water to remove bitumen to convert to heavy synthetic oil to flow through pipeline.

• Advantages of Heavy Oil from Oil Sands: large potential supplies, easily transported within and between countries, efficient distribution system in place

• Disadvantages: low net energy, major harmful impacts on land, air (more CO2 than the production of conventional crude oil), water, wildlife, climate (2-4 tons of oil sands and 2-5 barrels of water to produce 1 barrel of heavy synthetic oil), expensive.

13.3 - What Are the Advantages and Disadvantages of Using Natural Gas?

• Formed By: Decaying remains of marine life are buried under layers of rock and converted by pressure into oil and natural gas over time (TLDR: same process as petroleum)
• Forms when oil is trapped in a porous, sedimentary rock, underneath a harder, impermeable rock layer that doesn’t let the gas escape. AKA, it’s trapped IN a rock.

• Considered the “cleanest” fossil fuel - produces the least air pollutants and least CO2 when burned
• ½ as much CO2 as the CO2 generated by coal when burned for electricity
• Produces virtually no PM (ash/soot)
• Produces far less SOx, NOx than coal/oil, and no mercury at all!

• A vertical well is drilled down to sedimentary rock layer -> turns horizontally into rock layer -> perforating gun fractures rock layer around well to make it more permeable -> fracking fluid (water, salt, detergents, acids) is pumped into well at high pressure to crack the rock more and allow natural gas to flow out
• The natural gas is then collected at surface and shipped for processing and use while flowback water (fracking fluid) flows back out the well and is collected/stored in containers or ponds nearby
• TLDR: Hole drilled into shale rock, water/sand/chemicals pumped into borehole, pressure in bore causes fractures in the rock, gas from the shale flows into pipe and back to surface

• Environmental Consequences:
• Habitat Loss, CH4 Release (methane, a greenhouse gas)
• Possibility of well leaking and contaminating groundwater with fracking fluid/hydrocarbons
• Ponds can overflow/leach into ground, contaminating surface or ground waters with fracking fluid. This is toxic to plants/animals that rely on these water sources
• Depletion of ground/surface waters nearby (for fracking fluid)
• Increased seismic activity linked with wastewater injection wells (places where fracking fluid is stored, deep underground)

• Ample supply

• Versatile Fuel

• Medium net energy yield, low production cost

• Burns cleaner than oil and coal
• Less CO2 and other pollutants than other fossil fuels when burned

• Production/delivery may emit more CO2 and CH4 per unit of energy produced than coal
• CH4 is a LOT worse than CO2!!

• Fracking uses and pollutes large amounts of water

• Low price of natural gas can slow the shift to renewable energy -> must use full-cost pricing!

13.4 - What Are the Advantages and Disadvantages of Using Coal?

• Formed by: pressure from overlying rock and sediment layers compacting peat over long periods of time. The order above represents increasing energy density and quality, as well as increasing time periods of compaction
• The deeper a coal reserve is buried, the more pressure from overlying rock layers, forming more dense (better albeit rarer) coal

• High energy density == more energy released -> anthracite is best (highest quality but rarest)

• Environmental Consequences:
• Habitat destruction to clear land for mining (ex: all the harmful mining tactics, clear-cutting and all)
• Produces pollutants and releases the most CO2 when used for electricity generation
• Releases PM (soot,ash), irritating respiratory tracts of humans/animals
• Produces toxic ash contaminated with lead, mercury, arsenic
• Taken to landfills or stored in ash ponds; both can leak into ground/surface waters or into soil.
• Releases SOx and NOx (Sulfur/Nitrogen oxides), irritating respiratory systems and contributing to smog/acid precipitation

• Plentiful supply in many countries

• Medium-high net energy yield

• Low cost (when excluding environmental costs/full costs pricing)

• HIGH environmental impact from mining and burning
• Severe land disruption
• Water pollution (ex: acid mine drainage, mercury release)
• Air pollution (NOx, SOx, soot)
• Produces coal ash, which must be safely stored
• Mercury emissions can threaten human health

13.5 - What Are the Advantages and Disadvantages of Using Nuclear Power?

• Heat -> water to steam -> steam turns turbine -> turbine powers generator -> electricity!!

• How it Works:
• Neutron fired into nucleus of radioactive element (ex; Uranium, Plutonium)
• Nucleus breaks apart, releasing lots of energy (heat) and more neutrons that break more nuclei apart, releasing more and more energy.
• Radioactivity: the energy given off by the nucleus of a radioactive isotope (Uranium-235)
• Radioactive nuclei decay/breakdown, giving off energy (radiation) even without fission; fission just releases tons of energy at once
• Radioactive Half-Life: the amount of time it takes for 50% of a radioactive substance to decay (breakdown)
• The radioactive element is stored in fuel rods, submerged in water in the reactor core. Heat from the nuclear fission turns the water into steam.
• Control rods are lowered into the core as well to absorb neutrons and slow down the reaction, preventing a meltdown (explosion -> think nuclear weapons)
• Water pump brings in cool water to be turned into steam and also cools reactor down from overheating
• Cooling tower allows steam from turbine to condense back into liquid and cool down before being reused (giving off steam)

• This is because radioactive elements like uranium are limited. BUT:

• No Air Pollutants (PM, SOx/NOx) or GHG (CO2, CH4) are emitted when electricity is generated.

• Mining of uranium and plant construction still release GHGs.

• Only water vapor is released from electricity generation. It’s technically a GHG, but it stays in the atmosphere for a very very short time.

• Nuclear meltdown possibility and radioactive contamination are the greatest drawbacks.
• Ex - Three Mile Island: partial meltdown because testing error -> radiation released, no deaths or residual cancer cases
• Ex - Fukushima: earthquake/tsunami -> cooling pump failure -> meltdown, widespread radiation release
• Ex - Chernobyl: stuck cooling valve during test -> complete meltdown (reactor core exploded), widespread radiation release, many deaths
• Consequences of Nuclear Meltdowns:
• Contaminated Soil (radiation can remain in soil and harm plants and animals for a long, long time -> genetic mutations, DNA destruction)
• Radiation Spread (radiation can be carried by the wind over long distances, affecting ecosystems far beyond the meltdown site)

• Spent Fuel Rods: used fuel rods remain radioactive for millions of years, and they need to be stored in lead containers on site (at nuclear power plants)

• Mine Tailings: leftover rock and soil from mining may have radioactive elements that can contaminate water/soil nearby

• Water Use: nuclear power plants require lots of water and can deplete local surface/ground water sources

• Thermal Pollution: hot water from power plants released back into surface waters can cause thermal shock -> decrease O2 and suffocation of marine life

• Low Environmental Impact (without accidents)

• Emits 1/8th the CO2 of Coal, and none during electricity generation

• Very low accident risk in modern plants

• Low net energy yield

• High costs

• Fear of accidents

• Produces harmful, long-lived radioactive wastes

• Role in spread of nuclear weapons tech

Chapter 14 - Renewable Energy and Energy Efficiency

14.1 - Why Do We Need a New Energy Transition?

• Improve energy efficiency and reduce energy waste

• Decrease our dependence on nonrenewable fossil fuels

• Rely more on a mix of renewable energy from the sun, wind, geothermal, hydropower, and biomass.

• Modernize electrical grids that distribute energy produced from the above resources

14.2 - Why Is Improving Energy Efficiency and Reducing Energy Waste an Important Energy Resource?

• No energy-using device will operate at 100% efficiency; some energy is always lost as heat

• To Improve:
• Cogeneration (combined heat and power - two forms of energy from the same fuel source)
• Replace energy-wasting motors with hybrid or fully electric vehicles
• Recycle materials
• Use energy-efficient LED lighting
• Meter energy use
• Shut down unused computers and lights

• To Reduce Energy Use in Buildings (decreasing the amount of energy required to build larger buildings and heat/cool them):
• Insulate building, plug leafs
• Use energy-efficient windows
• Stop other heating and cooling losses
• Heat interior spaces more efficiently
• Heat water more efficiently
• Use energy-efficient appliances, computers, lighting
• Green roof or walls -> decreasing runoff, absorbing sun’s heat, decreasing energy needed for cooling building and surrounding area -> reduces heat island effect
• Sun lights on roof, windows on sides can decrease electricity used for lighting
• Recycled materials and stuff

• Sources of Waste: poorly insulated buildings, data centers filled with electronic servers, reliance on motor vehicles with internal combustion engines, nuclear/coal/natural gas plants, etc

• Small Scale Conservation:
• Lowering thermostat to use less heat or use AC less often
• Conserving water with native plants instead of grass, low flow shower heads, efficient toilets, dishwashers, dryers
• Energy efficient appliances, better insulation to keep more heat in home

• Large Scale Conservation:
• Improving fuel economy standards (20 to 30 mpg)
• Subsidizing electric vehicles, charging stations, hybrids
• Increased public transport (buses/light rails), green building design

• The U.S. is replacing its 100-year-old electrical grid system with digitally controlled, ultra-high-voltage (UHV), and hi-capacity system with super efficient transmission lines. It’ll cost around $800 Billion but save the U.S. $2 trillion during the period of building.

• Peak Demand: the time of day/year (early nighttime hours or very hot weather events) that electricity demand is the highest.
• Demand>supply: blackout
• To manage peak demand, some utilities use a variable price model for electricity
• Users pay a higher rate during peak demand hours or events (discourages use) and pay a lower rate/kWh when using a lower amount of energy (incentivizes lower overall use)

• Smart Grid: the idea of managing demand and energy sources in a more varied way; smart meters for variable price models, allowing rooftop solar to direct electricity back to grid, integrating more total energy sources -> renewable!!

• Passive solar design trap sun's heat and decrease energy from heating system (heat absorbing walls, 2x/3x paned windows)

• Well-insulated walls trap heat in winter and trap cold air from AC in summer, decreasing electricity used by AC unit and energy used by heating system

• Deciduous shade trees for landscaping; leaves block out sun in summer, no leaves in winter allow max sun exposure

• Native plants require less watering than traditional lawns while increasing the biodiversity of pollinators and requiring less fertilizer

• Low-flow showers, toilets, and dishwashers do the same job with less total water (less energy to purify and pump to homes)

• Rain barrels allow rain water to be used for watering plants or washing cars

• 28% of total U.S energy use came from transportation of goods and people in 2019.
• Improving fuel economy of US fleet of vehicles conserves energy as less gasoline/diesel is required to travel the same distance
• Hybrids have both gasoline and an electric motor, bringing higher MPG ratings
• Regenerative Braking System charges the electric battery which powers the electric motor
• PHEV: Regenerative braking system AND the ability to charge like a conventional EV. How cool.
• Electric Vehicles (EVs, BEVs) use no gasoline, but still require electricity
• They’re only as clean as their source of electricity.
• Public transit and carpooling are even better energy-saving transport options

14.3 - What Are the Advantages and Disadvantages of Using Solar Energy?

• Examples: Orienting building design to block sunlight in warmer months and absorb sunlight during colder months, double paned windows, southern facing windows with roof overhang, deciduous shade trees, skylight to decrease electricity use, dark colored floor absorbs heat, using sun’s heat to cook food in a solar oven

• Examples: solar water heaters capture sun’s heat in water or circulating fluid and transfer heat to warm water for home in place of electric/gas water heater, PV cells convert light rays directly into electricity

• Photons (particles carrying energy from sun) cause separation of charges between two semiconductor layers (neutron/proton); electrons separate from protons and flow through circuit to load, delivering energy as electricity

• PV Cells on a roof can directly power the building or send excess electricity back to the grid for other users -> you earn a credit from the utility company!

• Drawbacks:
• Intermittency (solar energy can only be generated during the day): “duck” curve shows lower energy demand during the day–energy is generated by PV cells from sunlight– but demand for energy is growing higher at night during peak hours.
• These can be solved by cheaper, larger batteries that can store energy generated during the day for use at night, but they aren’t cost-effective yet.

• Drawback: habitat destruction, light beams frying birds mid-air

• On FRQs, make sure to differentiate between community vs. rooftop solar energy.

• No Air Pollutants (NOx, SOx, PM) released when generating electricity

• No CO2 released when generating electricity -> no GHG emissions!

• Renewable!! Won’t run out!! Sun is everywhere!

• No mining fossil fuels!

• Semiconductor metals (silicon) still need to be mined to produce PV cells (solar panels)
• This brings all the problems associated with mining; disrupting habitats, polluting water with mine tailings, polluting air with PM, polluting atmosphere with CO2 emissions
• Silicon is limited!

• Solar Panel Farms can displace habitats

14.4 - What Are the Advantages and Disadvantages of Using Wind Power?

• Largest potential areas are in rural areas, and backup power may be needed (use a smart grid to connect wind farms together!)

• How it Works: kinetic energy of moving air spins a turbine (those huge blades), which in turn spins a generator which converts this mechanical energy into electricity
• More Complex: blades connected to gearbox by shaft that rotates; rotating gears create mechanical energy that the generator transforms into electricity
• Avg. the turbine can power 460 homes with a 15-30% capacity factor (% of total possible energy it could generate). It only produces electricity in 8-55 mpg winds, and a motorized drive within the shaft can turn the turbine to face the wind.
• In terms of location, they’re normally clustered in groups (wind projects/farms) in flat, open, usually rural areas, onshore or offshore. This makes service, repair, and building transmission lines to them easier while making it possible to share land with agriculture.
• Offshore wind = wind farms in oceans or lakes -> capitalizes on faster wind speeds but does require transmission lines built across long distances to reach land

• Non-depletable (isn’t decreased by its use, SUPERIOR TO RENEWABLE)

• No GHG emissions or air pollutants released when generating electricity

• No CO2 or NOx/SOx/PM emitted

• Can share land uses (doesn’t destroy habitat or cause soil/water contamination as Fossil fuels do)

• Intermittency (isn’t always available - wind chooses to exist sometimes)

• Can’t replace base-load power (sources that are ALWAYS AVAILABLE -> Fossil fuels, geothermal, nuclear)

• Can kill birds and bats, especially larger, migratory birds

• Can be considered an eyesore or source of noise pollution by some

14.5 - What Are the Advantages and Disadvantages of Using Geothermal Energy?

• To generate electricity: naturally heated water reservoirs underground are drilled into and piped up to the surface (or piped down into naturally heated rock layers), where it’s heated by the heat from the mantle which:
• turns water to steam -> steam turns turbine -> turbine to generator -> electricity!! -> water cooled in cooling tower and returned to ground to start over
• This is renewable energy because the heat from Earth’s core won’t run out until the Earth dies or if the groundwater is returned.

• 10 feet underground, the ground is a consistent 50-60˚F due to heat from the sun, NOT from geothermal energy from magma. Heat absorbing fluid is pumped through a pipe into a ground where it takes on heat from the ground or gives off heat to the ground.
• Summer: heat from home transfers to liquid and it transfers heat to ground, cooling house
• Winter: liquid takes heat from ground and transfers it to house, warming it

• Heated water is piped up to the surface and sent to homes or businesses to heat them.

• It’s technically renewable, if you pipe the water back into the ground for its reuse.

• Much less CO2 emissions than FF electricity

• No release of PM/SOx/NOx/CO, as compared to Fossil fuels

• Not everywhere on Earth has access to geothermal energy reaching close enough to the surface to drill down and access it

• Hydrogen sulfide can be released, which is toxic and/or lethal to humans and animals

• Cost of drilling deep into Earth can be costly and sometimes not even economically viable.

14.6 - What Are the Advantages and Disadvantages of Using Biomass as an Energy Source?

• Examples: wood, charcoal, dried animal waste, dead leaves

• Easy to harvest, Available, Cheap, and Free -> Subsistence Fuel

• Can be burned in Power Plants to generate electricity, although this is very uncommon.

• Burning biomass releases CO2, but doesn’t increase atmospheric CO2 levels like Fossil Fuel does:
• Burning biomass releases modern carbon (CO2 that was recently sequestered/taken out of the atmosphere)
• As a result, it’s considered “carbon neutral”
• Burning biomass also releases CO, NOx, PM, and VOCs -> respiratory irritants. With 3 billion people cooking on open biomass fires (in the developing world) and many cooking indoors, the effects are bad:
• Worsened asthma
• Bronchitis
• COPD
• Emphysema
• Eye irritation
• Meanwhile, burning fossil fuels releases fossil carbon that has been stored for millions of years. Thus, it is NOT carbon neutral.

• Environmental Consequences: deforestation, release of air pollutants
• Due to a lack of environmental protection laws and financial resources for other fuels in developing nations, more and more biomass deforestation occurs there. This causes:
• Habitat loss
• Soil erosion
• Loss of CO2 sequestering
• Air and H2O filtration loss
• Smog Formation (thanks to NOx, VOCs, PM)

• Biodiesel: liquid fuels produced specifically from plant oils (soy, canola, palm)
• Palm oil biodiesel emits 98% more greenhouse gasses than fossil fuels due to clearing of forest for palm plantations. NOT GOOD!
• It COULD be more sustainable if already cleared land is used or if plantations are continuously replaced. But these bring agricultural environmental consequences (ex: soil compaction, nutrient depletion)

• How it Forms: corn/sugarcane are broken down, yeast ferments it into ethanol, mixed with gasoline to be used in flex-fuel vehicles (E85/Flex Fuel)
• This decreases oil consumption for transport but is less efficient than pure gasoline

• It’s “renewable” to the extent that the production of corn is sustainable (sugarcane is perennial–lasts a long time–and is thus more sustainable)

• Algae produces oils that can be used as biofuels more sustainable than corn!

• Environmental Consequences: all the consequences of monocrop agriculture;
• Soil erosion
• Habitat loss
• GHG release (from compacted soils, tractors, fertilizers)
• Excess Water Use
• Lots of corn needed for fuel; can compete with human consumption

• Widely available

• Moderate costs

• Medium net energy (remember, the higher, the better!)

• No net CO2 increase (aka Carbon Neutral) IF HARVESTED, BURNED, AND REPLANTED SUSTAINABLY

• Plantations can help restore degraded lands

• Deforestation

• Clear-cutting -> soil erosion, water pollution, loss of wildlife habitat

• Can open ecosystems to invasive species

• Increases CO2 emissions if harvested/burned unsustainably

• Reduced CO2 emissions for some crops

• Medium net energy for biodiesel from oil plants

• Medium net energy for ethanol from sugarcane

• Can compete with food crops for land, raising food prices

• Fuel crops can be invasive

• Low net energy for corn ethanol and soybean biodiesel

• Higher CO2 emissions from corn ethanol

14.7 - What Are the Advantages and Disadvantages of Using Hydropower?

• Water flow is an indirect form of solar energy. It moves either with the current of river/tides or by falling through a channel in a dam. Top Producers: China, Brazil, Canada

• With a dam, operators can allow more/less water through the channel in the dam, increasing or decreasing electricity production (flows through channel -> turns turbine -> powers generator -> electricity

• This also allows for control of flow downstream, prevention of seasonal flooding due to high rainfall.

• Reservoirs are a source of recreation money (boating fees, tourism, increased property values, fishing, etc)

• Harmful Impacts: flooding of ecosystems behind dam, sedimentation (buildup of sediments behind dam)

• Benefits:
• Less impactful to surrounding ecosystem since no reservoir is formed and ecosystems behind dam aren’t flooded
• Doesn’t strop natural flow of sediments downstream, unlike water impoundment systems.

• Drawback: Doesn’t generate nearly as much power and may be unavailable in warmer seasons when river water levels are lower.

• Allows migratory fish to continue breeding + provides food source for predators (large birds, bears) and humans (fishing $)

• Alternative: “salmon cannon” - enables salmon to be captured or directed into a tube that carries them over the dam

• No GHG emissions when producing electricity (initial construction does require cement and machines that emit GHGs)
• Reservoir and dam can be tourist attractions
• Jobs to maintain the dam
• Reliable electricity source for nearby area
• No air pollutants released (No PM/SOx/NOx)

• Allows for control of seasonal flooding downstream
• Only 3% of dams are for hydroelectric. 37% are for recreation/scenic purposes. And the 2nd most common purpose is flood control (allowing humans to build closer to rivers in floodplains that would normally be flooded seasonally)
• This flood prevention is good for humans but deprives river floodplains of nutrient-rich sediment that supports plant growth and nearby wetland habitats

• Prevents upstream fish migration that need to swim upstream to spawning grounds

• Reservoir floods habitats behind dam (destroys forests/wetlands, river becomes a lake)

• Sedimentation changes upstream and downstream conditions
• Upstream becomes warmer (less dissolved O2) and rocky streambed habitats become covered in sediment
• Downstream loses sediment (important nutrient source), decreased water level, loses streambed habitats. Downstream wetlands especially suffer since nutrients in sediment don't reach them.

• Fossil Fuel consumption during dam construction -> increased evaporation due to larger surface area of reservoir + methane release due to anaerobic decomposition of organic matter in reservoir

• Loss of ecosystem services from downstream wetlands, potential loss of fishing revenue if salmon breeding is disrupted

• Human homes and businesses have to be relocated due to reservoir flooding.
• Initial construction of homes/businesses creates jobs but is costly
• Sediment buildup must be dredged (removed by crane) eventually

14.8 - What Are the Advantages and Disadvantages of Using Hydrogen as an Energy Source?

• How it Works: H2 gas enters fuel cell, split into protons and electrons by an electrolyte membrane that only lets protons pass through, electrons take alternative route around membrane (circuit) which generates electric current, O2 molecules break into individual O atoms and form H2O with two hydrogen ions -> water byproduct, only emissions from these.

• Key Challenge: Obtaining the hydrogen (gas is scarce on Earth, but it’s the most abundant in the universe). Separating H2 gas from other molecules (H2O, CH4) is very energy intensive.

• Main Processes to PRODUCE H:
• Steam Reforming: 95% of all H production. It involves turning natural gas (CH4) and using steam to separate the hydrogen gas from the methane.
• Emits CO2 and requires natural gas input/fossil fuel
• Electrolysis: Less common H production, but much more sustainable. It involves an electrical current applied to water, breaking it into O2 and H2
• No CO2 emission, but does require electricity

• H2 gas can be stored in pressurized tanks -> it can be transported for use creating electricity later, in a different location, unlike solar/hydro/wind, where the electricity must be used as soon as it’s generated and relatively close to the location.

• Can be used as fuel for vehicles, replacing gasoline, or to create ammonia for fertilizer, or in the chemical industry
• It emits no air pollutants (NOx/PM/CO) and only H2O.
• Manufacturing of many industrial chemicals requires H2 gas
• Can be stored as liquid or gas -> easy transport
• Hydrogen fuel cells are 80% efficient in converting chemical energy in H2 and O2 into electricity. In contrast, coal power plants are 35% efficient.

• Environmentally Friendly, as it does not emit CO2 when generating electricity.

• Revitalization of local Economies, as it increases local business opportunities

• Supplies both electricity and heat -> effective use of energy

• Helpful in emergencies, thanks to its ability to be stored

• 95% of H2 production requires methane (CH4) -> Hydrogen fuel cells are based on a non-renewable, carbon-emitting energy source
• If electrolysis is used instead, it’s only as sustainable as the electricity source
• Widespread hydrogen fuel usage would require widespread hydrogen fuel distribution networks (aka hydrogen fuel stations)
• Hydrogen fuel stored in gas form in vehicles would require MUCH larger tanks than current gasoline tanks

14.9 - How Can We Make the Transition to a More Sustainable Energy Future?

• Use full-cost pricing to include the harmful health and environmental costs of using fossil fuels and all other energy resources in their market prices

• Tax Carbon Emissions. THis is supported by most economists and many business leaders, and is now done in 40 countries. With this revenue, you can reduce taxes on income and wealth, promoting investments and research in new energy-efficient and renewable energy technologies.

• Decrease and eliminate government subsidies for fossil fuel industries, which are well-established, profitable businesses.

• Establish a national feed-in tariff that guarantees owners of find worms, solar power plants, and home solar systems a long-term price for energy.

• Mandate a certain percentage of the electricity generated by utility companies be from renewable resources (typically, this can be 20-40%)

• Increase government fuel efficiency (CAFE) standards for new vehicles to 43 k/liter (100 mpg) by 2040.

• Walk, bike, or use mass transit/carpool to get to work or school

• Drive only vehicles that get at least 17 km per liter (40 mpg)

• Have an energy audit done in the place you live

• Super Insulate the place where you live and plug all air leaks

• Use passive solar heating

• For cooling, open windows and use fans

• Use a programmable thermostat and energy-efficient heating and cooling systems, lights, and appliances

• Turn down your water heater’s thermostat to 43-49˚C (110-120˚F) and insulate hot water pipes

• Turn off lights, TVs, computers, and other electronics when not in use

• Wash laundry in cold water and air dry it on racks

• For sustainable economies, we need to reduce our use of fossil fuels (notably coal) and greatly increase energy efficiency, reduce energy waste, and use a mix of renewable energy resources (most specifically, solar and wind).

• Making this energy shift will have important economic and environmental benefits.

• Making the transition to a more sustainable energy future will require including the harmful environmental and health costs of all energy resources in their market prices, taxing carbon emissions, and greatly increasing government subsidies and research and development for improving energy efficiency and developing renewable energy resources.

Chapter 15 - Air Pollution

15.1 - What are the Major Outdoor Air Pollution Problems?

• Industrial Smog
• Caused primarily by burning coal

• Photochemical Smog
• Caused by emissions from motor vehicles, industrial facilities, power plants

• Air pollution (presence of chemicals in the atmosphere)
• Concentrations high enough to harm organisms, ecosystems, human-made chemicals, or alter climate

• Natural Sources
• Wind-blown dust
• Pollutants from wildfires and volcanic eruptions
• Volatile organics released by plants

• Human Sources
• Mostly in industrialized, urban areas
• Stationary: power plants, industrial facilities
• Mobile: motor vehicles

• FRQ TIP! Write about specific molecules/particles when talking about air pollution (AKA, specific air pollutants)

• Per the Clean Air Act, the EPA is responsible for monitoring/limiting Six Air Pollutant Criteria:
• SO2 (Sulfur Dioxide, from Coal Combustion)
• Respiratory Irritant, Smog, Acid Rain
• Worsens asthma and bronchitis
• Sulfur aerosols (suspended sulfate particles) block incoming sun, reducing visibility and photosynthesis
• Forms sulfurous (grey) smog
• Combines with water and O2 in atmosphere to form sulfuric acid -> acid rain
• NOx (Nitrogen Oxides, from all FF combustion and combustion in general)
• O3, Photochemical Smog, Acid Rain
• Worsens asthma and bronchitis
• Leads to tropospheric ozone (O3) formation -> photochemical smog
• Combines with water and O2 in atmosphere to form nitric acid -> acid rain
• CO (Carbon Monoxide, from incomplete combustion)
• O3, Lethal to Humans
• PM (Particulate matter, from FF/Biomass matter)
• Respiratory Irritant, Smog
• O3 (Ozone, from photochemical oxidation of NO2)
• Respiratory Irritant, Smog, Plant Damage
• Pb (Lead, from metal plants/waste incineration)
• Neurotoxicant

• Important Chemical Reactions:
• 2C + O2 → 2CO
• C + O2 → CO2
• N2 + O2 → 2NO
• 2NO + O2 → 2NO2
• S + O2 → SO2

• Ex: CO2 is NOT one of the 6 criteria pollutants mentioned in the Clean Air Act
• However, a 2007 Supreme Court Ruling gave the EPA the power to regulate GHG emissions, and it began doing so in 2009.

• CO2 does not directly lower air quality, from a human health standpoint
• Not toxic to organisms to breathe
• Not damaging to lungs/eyes
• Does not lead to smog, decreased visibility

• CO2 is a GHG, which leads to Earth Warming -> environmental/human health consequences

• FRQ TIP! Do NOT include CO2 as an air pollutant. Stick to SO2, NOx, O3, PM, VOCs

• Lead used to be a common gasoline additive until the EPA began phasing it out; now, all gasoline is UNLEADED.

• Vehicles made after 1974 are required to have catalytic converters to reduce NOx, CO, and Hydrocarbon emissions. Lead damages these converters.

• Lead is also a known neurotoxicant, damaging the nervous systems of humans

• Prevention:
• Replace lead pipes/plumbing fixtures containing lead solder
• Phase out leaded gasoline worldwide
• Phase out waste incineration
• Ban use of lead solder
• Ban use of lead in computer/TV monitors
• Ban lead glazing for ceramicware used to serve food
• Wash fresh fruits and vegetables

• Control:
• Remove leaded paint and lead dust from older houses and apartments
• Sharply reduce lead emissions from incinerators
• Remove lead from TV sets and computer monitors before incineration or land disposal
• Test blood for led by age 1
• Test for lead in existing ceramicware used to serve food

• Conditions:
• Sunlight: breaks down NO2 into NO and O, driving O3 formation
• Warmth: hotter atmosphere -> speedier O3 formation, evaporation of VOCs -> smog

• Precursors:
• N (Burning Fossil Fuels): binds with O2 to form NO2
• NO2: Sunlight breaks NO2 into NO and O
• Water Vapor and UV Radiation play a role in between this stage and the next. Maybe these break the NO2.
• O3: Free O binds with O2 to form O3
• VOCS: Volatile Organic Compounds + NO form photochemical oxidants
• VOCs are carbon-based compounds that volatilize (evaporate) easily, making them “smelly.” They come from gasoline, formaldehyde, cleaning fluids, oil-based paints, and even coniferous trees

• Formation:
• NO2 from car exhaust accumulates during morning/afternoon commute
• Daylight sun fuels breakdown of NO2 into NO + O
• Free O + Atmospheric O2 forms O3 (ozone)
• NO binds to VOCs to form photochemical oxidants
• O3 + photochemical oxidants form photochemical smog

1. NO2 from car exhaust accumulates during morning/afternoon commute

2. Daylight sun fuels breakdown of NO2 into NO + O

3. Free O + Atmospheric O2 forms O3 (ozone)
1. Peaks in the afternoon, when sunlight is direct and NO2 emissions from commuting have peaked. By evening, the free O from NO2 reacts with NO to reform NO2 and O2. This drops ozone levels. If there isn’t enough NO to react with, more O3 accumulates overnight.

• Environmental:
• O3 damages plant stomata
• Irritates animal respiratory tracts
• Reduces sunlight, limiting photosynthesis

• Human:
• Irritates eyes
• Respiratory irritant
• Worsens asthma, bronchitis, COPD

• Economic:
• Increased costs to treat health issues
• Lost productivity due to workers missing work (sick) or dying
• Decreased agricultural yields due to sunlight and stomata issues

• Energy: increased electricity production from renewable sources that don’t emit NOx OR using natural gas instead, which releases far less NOx than coal
• Solar, Wind, Hydro

• Vehicles: Decrease the number of vehicles on the road to curb NO2 emissions. Less vehicles == less gas == less VOCs!
• Carpooling, public transport, biking, walking, working from home

• Because cold air is trapped at the surface beneath the warmer layer, convection currents cannot carry pollutants up and away.

• These can take place in a location surrounded by mountain ranges and under the inversion layer or blown by sea breezes and trapped against a mountain range and under the conversion layer.

• Effects: air pollutants (smog/PM/ozone/SO2/NOx) are trapped closer to Earth’s surface
• Respiratory Irritation; asthma flare-ups, worsened COPD, emphysema
• Decreased Tourism Revenue
• Decreased photosynthetic rate

• Lightning Strikes: Convert N2 in atmosphere to NOx

• Plants: emit VOCs
• Ex: Terpenes/Ethylene from Pine/Fir/Spruce Trees form natural photochemical smog in Smoky Mountains

• Forest Fires: CO2, PM, NOx
• Combustion of biomass also releases CO2 and H2O vapor (GHGs)

• Volcanoes: SO2, PM, CO, NOx

• Respiration: all living things release CO2

• Aerobic Decomposition: decomposition of organic matter by decomposers, releases CO2

• Natural PM Sources: sea salt, pollen, ash from forest fires/volcanoes dust (windborne soil)
• Leads to Haze (scattering of sunlight and reduced visibility)

• Anaerobic Decomposition: decomposition of organic matter by decomposers in low/oxygen free environments -> releases CH4

15.2 - What is Acid Deposition and Why Is It a Problem?

• Caused mainly by NOx and SOx from coal-burning power plants and vehicle emissions remaining in the atmosphere for 2-14 days

• Threatens human health, aquatic life and ecosystems, forests, and human-built structures

• Wet Deposition: acidic rain, snow, fog, cloud vapor

• Dry Deposition: acidic particles

1. NOx and SOx react with O2 and H2O in the atmosphere to form nitric and sulfuric Acid

2. Acidic rain water (Higher H+ concentration) decreases soil and water pH, limiting tree growth in forests downwind from major SO2 and NOx sources

3. In the presence of water, sulfuric and nitric acid dissociate into sulfate, nitrate, and hydrogen ions

• Soil/Water Acidification (higher H+ concentration → lower pH → death)
• H+ ions displace or leech other positively charged nutrients (CA2+, K+) from soil while also making toxic metals (aluminum, mercury) more soluble in soil/water, slowing growth or killing plants/animals living in the soil or water.

• pH Tolerance
• As pH decreases (more acidic) outside optimal range for a species, population declines
• When pH leaves range of tolerance, they cannot survive at all (aluminum toxicity, disrupted blood osmolarity; Na+/Cl- balance disrupted at low pH)
• Indicator species can be surveyed and used to determine the conditions of an ecosystem (soil, water, etc)
• Ex: high whitemoss/filamentous algae population indicates pH < 6.0, high crustacean population indicates pH > 6.0

• Limestone (Calcium Carbonate): a natural base that neutralizes acidity, which increases pH.
• Calcium Carbonate (CaCO3) reacts with H+ ions to form HCO3 and Ca2+, which neutralizes acidic water/soil, moving it closer to a pH of 7
• Regions with limestone bedrock have some natural buffering of acid rain. Additionally, humans can add crushed limestone to soils/waters to neutralize.
• Acid rain can corrode human structures, especially those made from limestone.

• Limiting SO2 and NOx: These pollutants drive acid rain. Reducing it, through renewable energy sources, fluidized bed combustion and lower burning temp for existing coal power plants, dry or wet scrubbers, can reduce acid rain.

• Prevention:
• Reduce coal use and burn only low-sulfur coal
• Use natural gas and renewable energy resources in place of coal
• Remove SO2 and NOx from smokestack gases and remove NOx from motor vehicle exhaust
• Tax SO2 emissions

• Cleanup:
• Add lime to neutralize acidified lakes
• Add phosphate fertilizer to neutralize acidified lakes
• Add lime to neutralize acidified soils

• Prevention is Always Less Costly than Cleanup. Use Renewable Sources.

15.3 - What Are the Major Indoor Air Pollution Problems?

• Indoor burning of wood, charcoal, dung, crop residues, coal

• Greatest risk to low-income populations
• These nations rely on subsistence fuels (wood, manure, charcoal - biomass), which release CO, PM, NOx, VOCs (can cause deforestation) and are often combusted indoors w/ poor ventilation, leading to high concentrations.
• 3 Billion people globally cook with subsistence fuels, resulting in an estimated 3.5- 4.3 million deaths annually.

• Tobacco smoke

• Formaldehyde

• Radioactive radon-222 gas

• Very small particles
• More commercial fuels (coal, oil, natural gas) are used, typically burned in closed, well-ventilated furnaces or stoves.
• Major indoor pollutants in these nations come from chemicals in products: adhesives in furniture, cleaning supplies, insulation, or lead paint.

• To Remove: trained professionals w/ proper respiratory equipment, ventilation in the area, and plastic to seal off the area.

• Developed Nations: CO released into home by poor natural gas furnace ventilation, but can be detected by carbon monoxide detectors

• Undeveloped Nations: CO emitted from indoor biomass combustion for heating/cooking.

• Adhesives/sealants: chemicals used to glue carpet down, hold furniture together. Formaldehyde, for example, is a common adhesive in particle board and carpet glues (new carpet/furniture smell)

• Cleaners: common cleaners and deodorizers

• Plastics and Fabrics: both can release VOCs themselves or from adhesives used in production

• 2nd leading cause of lung cancer, after smoking.

• Use an airborne radon monitor to test homes for radon leaks, seal cracks in the foundation, and/or increase ventilation.

• Radon Exposure in CA Limited By: soil containing less radon -222 gas, and less basements (aka, no digging down and, therefore, less exposure)

• Dust settles in homes naturally, is disturbed by movement, entering air and then respiratory tract

• Mold develops in dark, damp, not well-ventilated areas (under sinks/showers, behind panels in walls and ceilings).
• Ex: black mold, known for releasing spores into the air. It’s especially harmful to the respiratory system, but can be removed by physically cleaning it out and fixing the water/ventilation issue that lead to mold forming.

• Damages central nervous system of children due to developing brain

15.4 - What Are The Health Effects of Air Pollution?

• Asthma

• Chronic Bronchitis

• Emphysema

• Lung Cancer

• Heart Attack

• Stroke

• 125k people per year in the U.S. develop cancer from breathing diesel fumes

• 14% of the U.S. population is exposed to excessive particulate pollution levels daily.
• Air Pollution can overwhelm our natural defenses (mucus, cilia, hairs)

15.5 - How Should We Deal with Air Pollution?

• Prevention:
• Walk, bike, or use mass transit
• Improve fuel efficiency
• Get older, polluting cars off the road

• Reduction:
• Require emission control devices
• Vapor Recovery Nozzle: captures hydrocarbon VOCs released from gasoline fuels during refueling through a separate tube inside the nozzle, returning them to an underground storage tank beneath the gas station and reducing VOCs/Benzene
• Catalytic Converter (CC): required on all vehicles after 1975, this contains metals (platinum, palladium) that bind to NOx, CO, and other hydrocarbons into CO2, N2, O2, and H2O.
• Inspect car exhaust systems twice a year
• Set strict emission standards

• Prevention:
• Ban indoor smoking
• Set strict formaldehyde emissions standards for carpet, furniture, and building materials
• Prevent radon infiltration
• Use naturally based cleaning agents, paints, and other products

• Reduction/Dilution:
• Use adjustable fresh air vents for work spaces
• Circulate air more frequently
• Circulate a building’s air through rooftop greenhouses
• Use solar cookers and efficient, vented wood-burning stoves

• What YOU can do:
• Test for radon/formaldehyde inside home, take corrective action
• Do not buy products containing formaldehyde
• Test home/workplace for asbestos fiber levels, check for crumbling materials
• Smoke outside or in a closed, well-ventilated area
• Wood-burning stoves/fireplaces and kerosene/gas burning heaters are properly installed, vented, and maintained
• Install carbon monoxide detectors in all sleeping areas
• Use fans to circulate air
• Grow house plants
• Don’t store gasoline/solvents/volatile hazardous chemicals inside home or attached garage
• Remove shoes before entering house to reduce inputs of dust/lead/pesticides

• Drive less, walk/bike/bus more

• Conserve electricity w/ smart bulbs and appliances (ex: LED bulbs > incandescent)

• Eat more plants and less meat

• Renewable, non-pollution emitting energy (solar, wind, hydroelectric)

• Clean Air Acts of 1970, 1977, 1990: allows EPA to set acceptable levels for criteria air pollutants. They can monitor emissions levels from power plants/facilities and tax, sue, or fine corporations that release too much emissions.
• EPA has established air quality standards for: carbon monoxide, nitrogen dioxide, sulfur dioxide, suspended particulate matter, ozone, and lead!
• Emission standards for 188 hazardous air pollutants (HAPs) as well (Toxic Release Inventory)
• New US regulations limit CO2 emissions from coal-fired power plants, and new air quality standards in China ban high-sulfur, high-ash-content coal in major cities.

• Pollution Credits: similar to ITQs for fish, these credits can be given to companies that reduce emissions well below EPA-set levels, who can then sell them to other companies that release more than acceptable levels.

• CAFE Vehicle Standards: requires the entire US “fleet” of vehicles to meet certain average fuel economy standards, requiring vehicle manufacturers to create more efficient vehicles that burn less gasoline and, therefore, release less NOx/PM/CO/CO2

• Pollutant levels have dropped despite increases in other factors, such as GDP, Pop, etc.

• This allows coal to be combusted at lower temperatures, emitting less NOx

• Electrostatic Precipitator: power plant/factory emissions are passed through a device with a negatively charged electrode, giving the particles a negative charge. They then stick to positively charged collection plates, trapping them. When the plates are discharged, the particles fall down into collection hoppers for disposal into landfills.

• Baghouse Filter: large fabric bag filters that trap PM as air from combustion/industrial process passes through. A shaker device knocks the trapped particles loose into a collection hopper below, where it’s taken to a landfill.

Chapter 16 - Waste Pollution and Its Impacts

16.1 - What Are the Causes and Effects of Water Pollution?

• Agricultural activities

• Sediment eroded from lands

• Fertilizers, pesticides, bacteria from livestock and food-processing wastes

• Industrial facilities

• Mining

• Untreated human wastewater

• Plastic
• In total, water pollution causes illness and death in humans/other species while disrupting ecosystems

• Examples: animal waste runoff from a CAFO (releases ammonia, fecal coliform bacteria), emissions from the smokestack of a coal power plant (releases CO2, NOx, SO2, PM), BP Oil Spill (releases hydrocarbons, benzene)

• Examples: urban runoff (motor oil, nitrate fertilizer, road salt, sediment), pesticides sprayed on agricultural fields (carried by wind, washed off large agricultural regions into bodies of water).
• In fact, estuaries and bays are polluted by many nonpoint pollutant sources from the large watersheds that empty into them.

• On an APES FRQ, Use Pollutants. Mention their specific names, their sources, their environmental and human effects, and their mitigation strategies.

• Typically, “Pollution” isn’t acceptable on an APES FRQ, except for specific types of pollution (Thermal, Noise, Sediment Pollution).

• Infectious Agents (Pathogens): cause diseases
• Ex: bacteria, viruses, protozoa, parasites
• Sources: human and animal wastes

• Oxygen-demanding Wastes: deplete dissolved oxygen needed by aquatic species
• Ex: biodegradable animal wastes and plant debris
• Sources: sewage, animal feedlots, food-processing facilities, paper mills

• Plant Nutrients: cause excessive growth of algae and other species
• Ex: nitrates (NO3) and phosphates (PO43-)
• Sources: sewage, animal wastes, inorganic fertilizers

• Organic Chemicals: add toxins to aquatic systems
• Ex: oil, gasoline, plastics, pesticides, cleaning solvents
• Sources: industry, farms, households

• Inorganic Chemicals: also adds toxins to aquatic systems
• Ex: acids, bases, salts, metal compounds
• Sources: industry, households, surface runoff, mining sites

• Sediments: disrupts photosynthesis, food webs, etc
• Ex: soil, silt
• Sources: land erosion

• Heavy Metals: causes cancer, disrupts immune and endocrine systems
• Ex: lead, mercury, arsenic
• Sources: unlined landfills, household chemicals, mining refuse, industrial discharges

• Thermal: makes some species vulnerable to disease
• Ex: heat
• Sources: electric power, industrial plants

16.2 - What Are the Major Pollution Problems in Streams and Lakes?

• Plus, flowing rivers/streams can dilute organic pollutants and heated water unless overloaded.

• Meanwhile, lakes and reservoirs are far less effective at diluting pollutants than streams, due to: stratified layers w/ little vertical mixing, little water flow, biological magnification of pollutants, 100+ years to flush/change the water
• Eutrophication is a natural transition and enrichment of a shallow lake, river mouth, or slow-moving stream, like the stages of aquatic succession (oligotrophic, mesotrophic, eutrophic).
• However, human activities cause cultural eutrophication, speeding up the natural process and potentially causing hypoxia/dead zones.

• Sediment buildup on the bottom (benthic zone) leads to higher nutrient levels, causing waterways to naturally shift from oligotrophic to mesotrophic to eutrophic.

1. Algae bloom covers surface of water, blocking sunlight and killing plants below the surface

2. Algae eventually die off; bacteria that break down dead algae use up O2 in the water (aerobic process)

3. Lower O2 levels -> less aquatic animals, especially fish (aka they DIE)

4. Bacteria use up even more O2 to decompose dead aquatic animals, creating a positive feedback loop (less O2 → more dead organisms → more bacterial decomposition → less O2)

• Summary: nutrients enter water causing algal bloom → reduced light penetration, killing plants → decomposers break down dead organic material, reducing DO2 levels → increase in suspended solids (silt) may increase temperature and decrease photosynthesis, reducing DO2 more → shifts in benthic plants, phytoplankton, macroinvertebrates, fish communities + loss of indicator species.

• Summary Once More: increase in nutrient load → algal bloom → increased BOD (Biochemical Oxygen Demand) → hypoxia → fish dieoff

• This N/P comes from: discharge from sewage treatment plants, animal waste from CAFOs, synthetic fertilizer from agricultural fields and lawns, mining and construction.

• Sources: power plants, steel mills, paper mills, other manufacturing plants (all of these use cool water from surface/groundwater sources to cool down machinery, returning the warmed water to local surface waters), urban stormwater runoff (carries heat from blacktop or asphalt), nuclear plants (requires LARGE amounts of water)
• Cooling Towers can help mitigate this hot water; they’re used to cool steam back into water and hold warmed water before returning it to local surface water. It’s standard in nuclear power plants but can be optimized to cool water better/longer.

16.3 - What Are the Major Groundwater Pollution Problems?

• As aquifers are the drinking water source for half the U.S. population, common pollutants are found in it (fertilizers/pesticides, gasoline, organic solvents, fracking).

• Sources: formerly in pesticides applied to agricultural fields (can still linger in soil), wood treatment chemicals to prevent rot, coal combustion, ash

• Effects: carcinogenic (lung/bladder/kidney cancer), endocrine disruptor (specifically the glucocorticoid system)

• Sources: coal combustion, trash incineration, burning medical waste, heating limestone for cement (mercury attaches to the PM released by burning/deposits in soil or water wherever PM settles, and it can be released if coal ash stored in ponds overflows into runoff)

• Effects: endocrine disruptor (inhibits estrogen and insulin, interfering with menstrual cycle and ovulation), teratogen (chemical harmful to developing fetuses - can accumulate in their brain. Reduce risk by eating less seafood)

• Sources: old paint in homes, old water pipes, soil contaminated w/ PM from vehicle exhaust before the 1970s (before lead was phased out of gas), fly ash (PM) of coal combustion

• Effects: neurotoxicant (damages CNS, especially in children), endocrine disruptor

16.4 - What Are the Major Ocean Pollution Problems?

• Effects of an Oil Spill:
• hydrocarbons in crude oil (petroleum) are toxic to many marine organisms and can kill them, especially through ingestion or absorption through gills/skin.

• Other effects: decreased visibility/photosynthesis due to less sunlight penetration, oil sticking to bird feathers and bottom of the ocean, killing w/ suffocation or direct toxicity)

• Oil can wash ashore, decreasing tourism revenue and killing fish → decreased fishing industry revenue, harming everything fish related.

• Oil can also settle deep into estuary habitat roots, and can be toxic to salt marsh grasses (kills them and loosens root structure → coastline erosion) and removes habitats used by fish/shellfish for breeding grounds.

• To Clean Up:

• Booms on surface to contain spread

• Ships w/ vacuum tubes to siphon oil off the surface or devices to skim it off

• Physical removal of oil from beach sand and rocks with towels, soap, shovels

• Chemical dispersants sprayed on oil slicks to break up and sink to the bottom
• This clears the surface BUT smothers bottom-dwellers.
• Dispersant chemicals may be harmful/

• Burning oil off surface

16.5 - How Can We Deal with Water Pollution?

• Prevent It!
• Reduce flow of pollution from land w/ land-use and energy/climate policy

• Use Nature to Treat Sewage!
• Soil conservation methods, fertilizers that slowly release nutrients, not steep land, reduce use/runoff of plant nutrients and pesticides, set discharge standards for nitrate chemicals from sewage treatment/industrial plants

• Use Natural Resources Better!
• Plant buffer zones of vegetation (zones where land remains untouched/undisturbed)

• Use Sewage Treatment!
• Septic tanks used in rural areas/about 25% of US homes
• wastewater/sewage treatment plants go through a series of treatments, which I shall go over in a minute.

• Clean Water Act (1972/1977)

• Marine Protection, Research, and Sanctuaries Act (1972)

• Clean Drinking Water Act (1975/1996)

• Toxic Substances Control Act (1976)

• Comprehensive Environmental Response COmpensation and Liability Act (CERCLA) (1980)

• Water Quality Act (1987)

• Oil Pollution Act (1990)

• Key Terms:
• Effluent (liquid waste/sewage discharged into a surface body of water, typically from a wastewater treatment plant)
• Sludge (inorganic solid waste that collects at the bottom of tanks in primary/secondary treatment)
• Water is spun/pumped off to concentrate it further, and dry, remaining physical waste is collected to be put in landfills, burned, or turned into fertilizer pellets.

1. Primary Treatment: physical separation and removal of large solid debris (leaves, plastic, sediment, toilet paper) using a screen or grate

2. Secondary Treatment: biological breakdown of organic matter (feces) by bacteria. This is an aerobic process and requires O2.
1. Removes 70% of phosphorus and 50% of Nitrates but DOESN'T REMOVE POPs (medications, pesticides)

3. Tertiary Treatment: chemical/ecological filters to remove most of the nitrates, phosphates, or remaining pollutants from secondary treatment discharge
1. This is critical because effluent discharged into surface waters w/ elevated nitrate or phosphate levels leads to eutrophication.
2. However, it’s expensive and not always used.
3. Disinfectant: UV Light, Ozone, Chlorine used to kill bacteria/pathogens. This is considered Part 3.
1. Some plants will go directly to this step, while others will go to Tertiary Treatment.

• Combined sewage and stormwater runoff systems can cause wastewater treatment facilities to flood during heavy rains, releasing raw sewage into surface waters
• Beneficial bc wastewater treatment plants treat storm runoff normally, but causes overflow during heavy rains
• Raw sewage releases contaminants: E. Coli, Ammonia, Nitrates, Phosphates, Endocrine Disruptors (medications)

• Even treated wastewater effluent released into surface water often has elevated N/P levels and endocrine disruptors.

• Sewage is what gets flushed down toilets, bathtubs, and sinks. This includes urine and feces.

• Waste must undergo multiple steps (e.g. ammonification, nitrification) before it can be assimilated into plants.

• While dog urine can “burn grass” (killing it due to the pee’s low pH and high nitrogen levels, brought by their carnivore diet), cow and chicken waste can be used as manure/fertilizer because their herbivore diet brings a greater variety of nutrients to their waste.

16.6 - Can Water Transfers Expand Water Supplies?

• Rapidly growing cities in northern China have helped to deplete underlying aquifers (2/3s of China’s 669 major cities have water shortages), so they’ve implemented the South-North Water Diversion Project to transfer water from the Yangtze River.

• In the U.S, water is diverted primarily to irrigate farm fields, such as the California State Water Project, which uses a maze of dams, pumped, aqueducts to transfer freshwater from the mountains to heavily-populated areas and agricultural regions.
• As a result, cities have grown and flourished (see San Diego and Los Angeles), and we’re able to supply many fruits and vegetables (Central Valley, for example, supplies half of the U.S’s fruits and veggies)

• Large water losses (evaporation/leaks in water-transfer systems)

• Degrading of ecosystems where the water is taken

• Very Expensive, displaces habitats and homes

• More pollution (ex: Sacramento River degraded, less freshwater flow)

16.7 - How Can We Manage and Sustain Wetlands?

• Ecosystem Services:
• Provisioning (habitat for animal and plant foods)
• Regulating (groundwater recharge, reduced floods, CO2 sequestration)
• Supporting (H2O filtration, pollinator habitats, nutrient cycling, pest control)
• Cultural (tourism revenue, fishing license fees, camping fees, ED/Med research)

• They are Disappearing! (US has lost more than half of its coastal/inland wetlands since 1900, other countries have lost more, trend is accelerating)
• How: people are draining, filling in, or covering over swamps/marshes/other wetlands for: rice fields/cropland, roads, cities and suburbs, extracting oil/minerals/ nat gas, eliminate breeding grounds for deadly insects
• Only 6% of remaining wetlands in the U.S. are federally protected; state and local wetland protection is weak and inconsistent. Plus, it’s difficult to restore, enhance, or create wetlands.

• Threats to Wetlands:
• Pollutants: nutrients (N/P), motor oil, pesticides, endocrine disruptors
• Development: wetlands can be filled in or drained to be developed into homes, parking lots, stores, or agricultural land.
• Water diversion upstream for flood control, agriculture, or drinking water can reduce water flow and dry up wetlands.
• Dam construction for flood control or hydroelectricity reduces water and sediment (N/P) flow to wetlands.
• Overfishing: disrupts food web of wetlands (decrease in fish predators, increase in prey, unbalanced ecosystem, ecosystem collapse)

• What can We Do?
• Cover Crops, Animal manure Management, Riparian Buffers, Enhanced nutrient removal, Septic Tank Upgrades
• Mitigation Banking: allows the destruction of wetlands as long as an equal or greater area of the same type of wetland is created, enhanced, or restored.
• Not very effective; at least half the attempts to create new wetlands failed, and most didn’t provide the ecosystem services of natural wetlands.
• However, it’s a profitable business, creating wetland branks or credits that bankers sell to developers to enhance or restore.
• Make sure to use mitigation banking as a last resort, and that the replacement wetland is created and evaluated before existing wetlands are destroyed.

• There are a number of ways to purify drinking water, but the most effective and least costly strategy is pollution prevention.

• The key to protecting the oceans is to reduce the flow of pollution from land and air, and from streams emptying into ocean waters.

• Reducing water pollution requires that we prevent it, work with nature in treating sewage, and use natural resources far more efficiently.

Chapter 17 - Terrestrial Pollution and Waste

17.1 - What Environmental Problems Are Related to Solid and Hazardous Wastes?

• Industrial: produced by mines, farms, construction, demolition, and other industries supplying people with goods/services

• Municipal: also named garbage/trash, it consists of the solid waste from homes/workplaces that aren’t factories. This includes paper, cardboard, food wastes, cans, bottles, furniture, plastics, etc

• Most plastics come from beaches/rivers/storm drains/etc, and the rest are dumped into the ocean by ships. Developed countries usually have landfills or incinerators. Undeveloped countries have open dumps.

• Improper Handling == air/water pollution, degradation of ecosystems, health threats.

• Main Classes:
• Organic Compounds (various solvents, pesticides, PCBs, dioxins)
• Toxic Heavy Metals (lead, mercury, arsenic)

• Also includes nuclear waste. Additionally, developed countries make 80-90% of waste.

17.2 - How Should We Deal with Solid Waste?

• We should prioritize reduce -> reuse -> recycle/compost -> incinerate -> bury

• Refuse:don’t use it

• Reduce: use less of it

• Reuse: use it again and again.

• Recycle: convert used items to useful items. Composting, for example, is a form of recycling, and it mimics nature by using bacteria/decomposers to break down biodegradable organic wastes into cool stuff.

• Follow the four R’s of resource use

• Ask if the item is really necessary

• rent/borrow/barter goods, buy second hand, etc

• Buy reusable/recyclable things

• Buy products with little packaging

• Avoid disposables, use reusables whenever possible

• Cook with whole, fresh foods, avoiding processed stuff

• Discontinue junk mail, use online things

• Change industrial processes to eliminate/reduce the use of harmful chemicals

• Redesign manufacturing processes/products to use less material and energy

• Develop products that are easy to repair/reuse/remanufacture/compost/recycle

• Establish cradle-to-cradle responsibility laws that require companies to take back various consumer products for recycling/remanufacturing

• Eliminate or reduce unnecessary packaging

• Use fee-per-bag solid waste collection systems

17.3 - Why Are Refusing, Reducing, Reusing, and Recycling so Important?

• Refusal: Do I really need this?

• Reducing: How many of these do I actually need?

• Reusing: Is this something I can use more than once?

• Recycling: can this be converted into the same or different product when I’m done with it?

• Design products and societies that produce no waste

• Live off the Earth’s endless supply of solar energy

• Respect and mimic the Earth’s life sustaining biodiversity.

• Ban or severely restrict the disposal of certain items, as well as the use of certain throwaway items.

• Use reusable items whenever necessary. If you can’t (ex: plastic bag), tax it.

• Implement “shared use” - tool libraries instead of a set for every house, toy libraries, etc

• Upcycling v. Downcycling: recycled into a more useful form vs. a less useful form than the original item

• Primary Recycling: using materials again for the same purpose (aluminum can -> new can)

• Secondary Recycling: downcycling/upcycling waste materials into different products (used tires -> sandals)

• Steps of Recycling: collection of materials -> conversion into new products -> selling these products. It’s environmentally/economically successful.

• E-Waste Recycling saves many precious earth minerals, but <17% are recycled.

• Composting is also cool; it can supply plant nutrients, slow soil erosion, retain water, and improve crop yields. Successful composting must control odors and exclude toxic materials.
• Advantages: reduces landfill volume, produces rich organic matter than can enhance water holding capacity/nutrient levels, produces valuable product to sell, reduces amount of methane released by anaerobic decomposition of organic matter in landfills
• Disadvantages: needs a proper mix of “browns” to “greens” (carbon to nitrogen - 30:1), foul smell if not properly rotated, attracting rodents/pests

• Centralized Materials-Recovery Facilities: one way to recycle; machines and workers separate mixed waste to recover valuable materials for sale to manufacturers as raw materials, with the remaining stuff recycled or burned.
• Expensive to build/operate/maintain, can emit CO2/air pollutants if not handled properly, and produce a toxic ash that must be disposed of.
• Also requires a constant stream of trash to be financially viable, incentivising more waste; MRFs don’t help encourage reuse and waste reduction.
• People also throw recyclables into recycling bins, straining MRFs.

• Source Separation Approach: separating trash into recyclable categories (glass, paper, metals, plastics, compostable materials), producing much less air/ water pollution AND costing less to implement while saving energy.

• Advantages:
• Creates 6-10x as many jobs
• Reduces energy/mineral use and air/water pollution
• Reduces greenhouse gas emissions
• Reduces solid waste and the amount that piles in landfills
• The environmental, health, and economic benefits > costs

• Disadvantages:
• Can cost more than burying in areas with ample landfill space
• Reduces profits for landfill/incinerator owners
• Inconvenient for some, can also be a tax burden for others

• This industry is the 5th largest energy consumer in the world, and uses the most water to produce a metric ton of product. Recycled paper is easy to make, too, and produces 35% less water pollution and 74% less air pollution than regular.

• Only 7% of all wastes are recycled, because too many plastic resins + some not designed for recycling, making landfill placement cheaper.

• Bioplastics, made with corn/soy/sugarcane/switchgrass/chicken feathers/some garbage, are lighter, stronger, and cheaper, requiring less energy/pollution. Some are more environmentally friendly than others.

17.4 - What Are the Advantages and Disadvantages of Burning or Burying Solid Waste?

• Produces gases, which must be filtered to remove pollutants, and ash, which must be treated properly

• Only 13% of MSW waste in US is incinerated because past incinerators were highly polluting and poorly regulating + competes with low-cost landfills

• Landfills emit more air pollutants than waste-to-energy incinerators BUT the ash contains toxic chemicals.

• Advantages:
• Reduces trash volume
• Produces energy
• Concentrates hazardous substances into ash for burial
• Sale of energy reduces cost

• Disadvantages:
• Expensive to build
• Produces hazardous waste
• Emits some CO2 and other air pollutants
• Encourages waste production

• Labor is cheaper in other parts of the world, and environmental regulation is more lax.

• Clay/Plastic Bottom Liner: layer of clay/plastic on the bottom of a hole in the ground; prevents pollutants from leaking out into soil/groundwater

• Leachate Collection System: system of tubes/pipes at the bottom to collect leachate (water draining through waste and carrying pollutants) for treatment and disposal.

• Methane Recovery System: system of tubes/pipes to collect that methane produced by anaerobic decomposition in the landfill. Methane can then be used to generate electricity or heat buildings.

• Clay Cap: clay-soil mixture used to cover the landfill once it’s full. This keeps out animals, keeps in the smell, and allows vegetation to grow.

• The largest percentage of landfill materials is paper. Other materials: yard waste, plastics, metals, wood, glass, food waste

• Advantages:
• Low operating costs
• Can handle large amounts of waste
• Filled land can be used for other purposes
• No shortage of landfill space in many areas

• Disadvantages:
• noise/traffic/dust
• Releases greenhouse gases (methane, CO2) unless they’re collected
• Output approach that encourages waste production
• Eventually leaks and can contaminate groundwater

• Cardboard/food wrappers that have too much food residue and can’t be recycled

• Rubber, plastic films/wraps

• Styrofoam

• Food, yard waste, paper (they can and do go in landfills, but they should be recycled)

• Hazardous waste (antifreeze, motor oil, cleaners, electronics, car batteries)

• Metals (copper/aluminum - should be recycled)

• Old tires (often left in large piles that hold standing water, ideal for mosquito breeding)

• Environmental impacts (groundwater contamination with heavy metals and bacteria if leachate leaks, greenhouse gases released due to decomposition)

• NIMBY (Not In My BackYard): idea that communities don’t want landfills near them due to smell/sight, attracting animals, and groundwater contamination.

• They’re often placed near low-income, minority communities that don’t have the resources or political power to fight against these decisions.

17.5 - How Should We Deal With Hazardous Waste?

• bioremediation: bacteria/enzymes help destroy toxic/hazardous substances or convert them to harmless compounds. Often used on contaminated soil and is cheap but takes a while

• Phytoremediation: using natural or genetically engineered plants to remove contaminants from polluted soil and water. Still being evaluated, is slow compared to alternatives

• Incineration (has the same advantages/disadvantages as burning solid wastes)

• Plasma gasification: using arcs of electrical energy to produce very high temperatures, vaporizing trash in the absence of oxygen. This reduces the volume of a given amount of waste by 99%, produces a synthetic gaseous fuel, and encases toxic metals and other materials in glassy lumps of rock. However, it’s very costly.
• Advantages:
• Produces a mixture of CO and H2 that can be used as a fuel
• Mobile, and easy to move to different sites
• Produces no toxic ash
• Disadvantages:
• High cost
• Produces CO2 and CO
• Can release particulates and chlorine gas
• Can vaporize and release toxic metals and radioactive elements

• Advantages:
• Safe if sites are chosen carefully
• Wastes can often be retrieved
• Low costs

• Disadvantages:
• Leaks can occur from corrosion of well casing
• Emits CO2 and other air pollutants
• Output approach that encourages waste production

• Advantages:
• Low cost
• Wastes can often be retrieved
• Wastes can be stored indefinitely with secure double liners

• Disadvantages:
• Water pollution from leaking liners and overflows
• Air pollution from VOCs
• Output approach that encourages waste production

17.6 - How Can We Shift to a Low-Waste Economy?

• Health risks from incinerators and landfills are low but much higher for people living NEAR them. So, the goal should be “not in my back yard” (NIMBY) or “not on planet Earth” (NOPE)

1. Market prices of products don’t include the environmental and health costs associated with production, use, and discarding.

2. Economic playing field is uneven/resources extraction industries in some countries receive more government tax breaks and subsidies than reuse and recycling industries.

3. The demand -> price paid for recycled materials fluctuates because it’s not a high enough priority for most governments, businesses, and individuals

• Also, “bottle bills” (basically california’s CRV tax on recyclable cans and bottles)

• Fee-per-bag collection system, charging households for the trash they throw away but not for their recyclable and reusable wastes

• Pass laws requiring companies to take back and recycle/reuse packaging and electronic waste discarded by consumers, or encourage government purchases of recycled products to help increase their demand.

Chapter 18 - Environmental Health

18.1 - What Major Health Hazards Do We Face?

• Biological Hazards: from 14k pathogens (microorganisms that can cause disease in other organisms, such as bacteria, viruses, parasites, protozoa, and fungi.)

• Chemical Hazards: harmful chemicals in the air, water, soil, food, and man made products.

• Natural Hazards: fire,earthquakes, volcanic eruptions, floods, tornadoes, hurricanes, etc

• Cultural Hazards: stuff in daily life (unsafe working conditions, criminal assault, poverty)

• Lifestyle Choices: smoking, making poor food choices, sedentary lifestyle

18.2 - How Do Biological Hazards Threaten Human Health?

1. Lower Respiratory Infections (Bacteria/Viruses): 3.1 million deaths

2. Tuberculosis (Bacteria): 1.5 million deaths

3. HIV/AIDS (Virus): 1.1 million deaths

4. Hepatitis B (Virus): 780k deaths

5. Diarrheal Diseases (Bacteria/Viruses): 760k deaths

6. Malaria (Protozoa): 429k deaths

7. Measles (Virus): 114k deaths

• Infectious diseases are still a serious threat due to the development of genetic immunity to widely used antibiotics. Plus, some vector species (mosquitos) have become immune to some pesticides and other forms of pest control.

• Warmer Temperatures will allow some infectious diseases to spread more easily from tropical to temperate areas because the vector species that spread them (ex: mosquitos and other insects) breed more rapidly in warmer climates.

• Increase research on tropical diseases and vaccines

• Reduce poverty and malnutrition

• Improve drinking water quality

• Reduce unnecessary use of antibiotics

• Sharply reduce the use of antibiotics on livestock

• Immunize children against major viral diseases

• Provide oral rehydration for diarrhea victims

• Conduct global campaign to reduce HIV/AIDS

18.3 - How Do Chemical Hazards Threaten Human Health?

1. Carcinogens: chemicals, some types of radiation, and certain viruses that cause or promote cancer (ex: arsenic, benzene, formaldehyde, PCBs, radon, tobacco smoke, vinyl chloride)

2. Mutagens: cause or increase the frequency of mutations in cells. Most cause no harm, but some can lead to cancers and other disorders, and those occurring in reproductive cells can spread to offspring and future generations (includes chemicals and forms of radiation)

3. Teratogens: harm or cause birth defects in a fetus or embryo (alcohol, mercury, PCBs)

• The Immune System has specialized cells and tissues that protect the body from diseases and harmful substances with antibodies (specialized proteins). Certain chemicals can weaken this system and leave the body vulnerable to attacks from allergens/bacteria/viruses/protozoa.
• Arsenic, methylmercury, and dioxins

• Nervous System includes the brain, spinal cord, and peripheral nerves. Neurotoxins can cause behavioral changes, learning disabilities, ADD, paralysis, and death.
• PCBs, arsenic, lead, and certain pesticides

• It’s gotten so bad that 1/12 women of childbearing age have enough mercury to harm the fetus.

• Phase out waste incineration

• Remove mercury from coal before it’s burned

• Switch from coal to natural gas and renewable energy sources

• Sharply reduce mercury emissions from coal-burning plants and incinerators

• Label all products containing mercury

• Collect and recycle batteries and other products containing mercury

• Hormonally Active Agents/Endocrine Disruptors also attach to these cell receptors, disrupting the endocrine systems (ex: Atrazine, herbicides, organophosphate pesticides, dioxins, lead, mercury)

• Some HAAs can act as Hormone Mimics (ex: BPA, mimicking estrogen and binding to their receptors). Others can act as Hormone Blockers, preventing natural hormones from attaching to their receptors.

• Eat certified organic produce and meats

• Avoid processed, prepackaged, and canned foods

• Use glass and ceramic cookware

• Store food/drinks in glass containers

• Use only natural cleaning and personal care products

• Use natural fabric shower curtains, not vinyl

• Use only glass baby bottles and BPA free, phthalate-free sipping cups, pacifiers, toys.

18.4 - How Can We Evaluate Risks from Chemical Hazards?

• Toxicity: measure of the ability of a substance to cause illness, injury, or death. Any synthetic or natural chemical can be harmful if ingested/inhaled in a large enough quantity.

• Dose: amount of a harmful chemical that a person has ingested/inhaled/absorbed at any one time.

• Age and genetic makeup are other factors that may influence a chemical’s effects. Older people are less sensitive to chemicals, and some may be sensitive to toxins (multiple chemical sensitivity)

• Synergistic Interaction (Synergy): occurs when two or more compounds interact and magnify each other’s effects.

• Solubility of the chemical affects its level of harm; water-soluble chemicals can move through the environment and get into water supplies and the water in our cells, while oil-soluble chemicals can just penetrate our cell membrane and accumulate in our body tissues.

• Persistence of a chemical (resistance to breaking down) increases how long these chemicals remain in the environment nad have an effect (and, therefore, remain in our body)

• Acute Effect: immediate or rapid harmful reaction (dizziness to death)

• Chronic Effect: permanent or long-lasting consequence of exposure to a single or repeated dose of a harmful substance (ex: kidney or liver damage)

• Lethal Dose: the dose that will kill an animal. We use the median lethal dose (LD50, the dose that could kill 50% of a test organism in a test population in a given period, usually in milligrams per body weight-kg)

• Types of Dose Response Curves:
• Nonthreshold Dose-Response Model: any dosage causes harm. More dosage=harm.
• Threshold Dose-Response Model: a certain level (threshold) of exposure must be reached before any detectable harmful effects occur (bc body can repair them)
• Unconventional Model: harmful effects increase with dosage to a certain point and then decrease

• How: we divide the LD50 or the ED50 (Effective Dose - causes non-lethal effect in 50% of tested population, like infertility or paralysis or cancer) by 1000 for extreme caution.

• More Humane: computer simulations, individual animal cells

• We should probably care, because they COULD have long-term effects. But they’re probably minor

• We don’t know much because of insufficient data, high costs of regulation (10% of the nearly 85k registered synthetic chemicals have been thoroughly screened for toxicity, and only 2% have been adequately tested to see what kind of toxin they are)

• Some countries ship their hazardous waste to other countries for processing and disposal. The Basel Convention (int. treaty) bans this. But illegal shipping still happens.
• POPs (Persistent Organic Pollutants), because of their persistence, can be transported long distances by wind and water, and spread from country to country.
• The dirty dozen includes DDT, eight other chlorine-containing persistent pesticides, PCBs, dioxins, and furans.

• We would assume that new chemicals/technologies could be harmful until scientific studies show otherwise

• Existing chemicals/technologies that appear to have a strong change of causing harm should be removed from the market until we could establish their safety

• TLDR: With the production of chemical products, the burden of reducing and assessing risk would lie with the manufacturer before the product is put on the market.

18.5 - How Do We Perceive and Avoid Risks?

• Greatest Risk is Poverty (due to malnutrition, increased susceptibility to normally nonfatal infectious diseases, and fatal infectious diseases transmitted by unsafe drinking water/inadequate health care)
• Other Risks in Shortening Lifespan: poverty, being born male, smoking, obesity

• Tobacco use leads the cause of death in the United States.

• Usually, human reliability is MUCH lower than technology reliability and is impossible to predict.

1. Fear, causing people to overestimate risks and worry more about catastrophic events than common ones (ex: overestimating natural disaster death tolls vs. smoking, flu, car accidents)

2. Degree of Control individuals have in a given situation (more fear if they can’t control)

3. Whether a risk is catastrophic or chronic (more frightened by news of catastrophic events vs. a cause of death like smoking)

4. Optimism Bias (risks don’t apply to them - people may get upset when seeing people drive erratically while talking on the phone while believing that they’re just fine when they do it)

5. Instant Gratification vs. Long-term Harm: unsafe sex, smoking cigarettes, and eating too much give instant pleasure with long-term consequences.

• Compare them.

• Determine how much risk you’re willing to take.

• Evaluate the actual risk involved.

• Concentrate on evaluating and carefully making important lifestyle choices.

• We face significant hazards from infectious diseases such as flu, AIDS, tuberculosis, diarrheal diseases, and malaria, and from exposure to chemicals that can cause cancers and birth defects, as well as chemicals that can disrupt the human immune, nervous, and endocrine systems.

• Because of the difficulty of evaluating the harm caused by exposure to chemicals, many health scientists call for much greater emphasis on pollution prevention.

• By becoming informed, thinking critically about risks, and making careful choices, we can reduce the major risks we face

Chapter 19 - Environmental Change

19.1 - What Role Do Humans Play in the Loss of Species and Ecosystem Services?

• Causes: sustained and significant global warming/cooling, large changes in sea levels and ocean water acidity, catastrophic conditions (volcanic eruptions, large asteroids)

• Effects: destroy life but provide opportunities for new life forms to emerge/diversify and occupy emptied ecological niches; each mass extinction is followed by a resurgence in Earth’s biodiversity, albeit after a few million years.

• Humans are exacerbating species extinction, and the current annual extinction rate is at least 1000x the natural background extinction rate. It’s likely to rise to at least 10k times the background rate (climate change, habitat loss, ocean acidification, other human activities)
• This is bad! 20-50% of the world’s 2 million species could vanish by 2100, and we’re literally entering a 6th mass extinction, caused by HUMAN ACTIVITIES!’
• This would impair some vital ecosystem services (air/water purification, natural pest control, pollination); 15/24 of Earth’s major ecosystems are in decline!

• The rate of extinction and the resulting threats to ecosystem services are likely to increase sharply in the next 50-100 years because of the harmful environmental effects of the rapidly growing human population and its gluttonous use of resources

• We’re eliminating, degrading, fragmenting, and simplifying many biologically diverse environments that serve as potential sites for new species to emerge, thus further reducing the long-term recovery of biodiversity while contributing to the extinction rate.

• Big size, slow movement speed, the tasty ones, and those with valuable parts (tusks/skin)

• Low reproductive rate (K-strategist)

• Specialized niche

• Narrow distribution

• Feeding at a high trophic level

• Fixed migratory patterns

• Rare, commercially viable

• Requires large territories

19.2 - Why Should We Try to Sustain Wild Species and the Ecosystem Services they Provide?

1. World’s species provide vital economic services to keep us alive and support our economies

2. Many species contribute to economic services that we depend on (ex: food crops, wood, paper, medicinal substances)
1. Bioprospectors: search tropic forests/ecosystems to find plants and animals that can be used to make medicinal drugs - we’ve only examined 0.5% of them!
2. Also they provide economic benefits - ecotourism (environmentally responsible travel to natural areas, generating more than $1 Million PER MINUTE in tourist expenditures worldwide.)
1. You get more money from looking at a lion ($515k through ecotourism) than from killing it for its skin ($10k)

3. It’ll take 5-10 million years for natural speciation to replace the species we’re likely to wipe out this century.

4. Wild species have a RIGHT to exist, regardless of how useful they are!

19.3 - How Do Humans Accelerate Species Extinction And Degradation of Ecosystem Services?

• Habitat loss/destruction/degradation/fragmentation is the greatest threat, especially deforestation in tropical areas due to their ecosystem services. Next comes the destruction of coastal wetlands and coral reefs, the plowing of grasslands for crops, and water pollution

• Habitat Fragmentation: when a large, intact area of habitat is divided into smaller, habitat islands (isolated patches) through roads, logging operations, crop fields, and other urban developments.
• Reduces tree cover, blocks animal migration routes, divides populations int isolated small groups more vulnerable to predators/disease/competitor species/catastrophic events
• Also creates barriers that limit the abilities of some species to disperse and colonize areas, locate adequate food supplies, and find mates.
• Also, edge effect (more edge habitat - boundary between diff habitat types), as abiotic factors change around the edges and can lead to a change in the pop of species/community structure at the boundary
• Reaction to edge effect == edge sensitivity (some benefit, some have their habitat reduced - poison ivy benefits in edge habitat, while some bird species like ecotone - boundary between forest and adjacent open land)

• Invasive Species can be beneficial (ex: corn/wheat/rice give food, some control pests, etc) but when they don’t face the natural predators/diseases/parasites/competitors that native species face, they can outcompete them for food, disrupt ecosystem services, etc.
• They cause $1.4 trillion/year in economic and ecological damages, globally, about $2.7 million lost per minute.
• They travel to places (especially Florida) through cars/trucks, people bringing plants, plants carrying insects, etc. Burmese pythons, for example, disrupt the food webs and ecosystem services of the everglades. They’re hard to control as it’s hard to capture or kill them and they reproduce fast.
• However, 1/100 species that invade an area are able to establish a self-sustaining population and reduce the biodiversity of the invaded ecosystem + some species even increase the biodiversity of the areas they’re in by creating new niches.
• The best way to limit this is to prevent them from being introduced into ecosystems, by researching the characteristics of invaders and working to understand the types of habitats they invade + establish treaties to ban exports of species from countries.

• Some protected animals are illegally killed for their valuable parts, or are captured (illegal wildlife smuggling) and sold, where ⅔ die in transit. Rhino horn, for example, composed of keratin, is highly valuable for its medicinal use in Asian countries. Plus, elephant ivory tusks are also valuable. So are tigers, from their bones to their pps.
• As habitats for these animals shrink, they damage farmers’ crops while trying to find food.
• Birds used to be illegally transported a lot (until the Wild Bird Conservation Act banning the import of birds b/c disease and endangerment).

• Bushmeat is another example, and in West/Central Africa, it’s a highly valuable source of food. However, hunting them has become much, much easier, and the habitats of them are slowly decreasing. Plus, the hunting of this species has led to extinctions + HIV/AIDS spread.

19.4 - How Can We Sustain Wild Species and the Ecosystem Services They Provide?

• Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITIES): bans hunting/capturing/selling of threatened or endangered species and restricts international trade of 5.6k animal and 30k plant species at risk of being threatened. Has helped elephants/crocodiles/chimps but the effects are varied b/c enforcement varies and convicted violators only pay small fines.

• Convention on Biological Diversity: legally commits participating governments to reduce the global rate of biodiversity loss and to share the benefits from use of the world’s genetic resources + includes efforts to prevent or control the spread of invasive species.

• No land or water use projects/activities may be carried out if it would jeopardize or endanger a listed species or destroy critical habitat, and citizens can be fined if it's on private land to + private landowners are given incentives not to do this.

• Also requires all commercial shipments of wildlife/wildlife products entering or leaving the country to be transported through specific US airports and ocean ports where inspectors can confiscate illegal cargo and fine violators

• 90% of ESA-protected species are recovering, and 99% of listed species have been saved from extinction!

• However, mining/oil drilling/use of off road vehicles are legally allowed in 60% of the nation’s wildlife refuges.

• Arboretum: land set aside for protecting, studying, and displaying species of trees/shrubs

• Botanical Gardens: contain living plants that represent ⅓ of the world’s known plant species but only 3% of the world’s rare and threatened plant species + have limited space and funding to preserve them.

• Using farms could help take pressure off some threatened or endangered species.

• We are hastening the extinction of wild species and degrading the ecosystem services they provide by destroying and degrading natural habitats, introducing harmful invasive species, and increasing human population growth, pollution, climate change, and overexploitation.

• We should avoid causing or hastening the extinction of wild species because of the ecosystem and economic services they provide and because their existence should not depend primarily on their usefulness to us.

• We can work to prevent the extinction of species and to protect overall biodiversity and ecosystem services by establishing and enforcing environmental laws and treaties and by creating and protecting wildlife sanctuaries.

Chapter 20 - Atmospheric Change

20.1 - How Have We Depleted Ozone in the Stratosphere and What Can We Do About It?

• This ozone depletion could harm us. Quite obviously.

• Scientists found that CFCs are persistent chemicals that destroy protective ozone in the stratosphere, with 75-85% of ozone losses since 1976 caused by them.

• CFCs remain in atmosphere for a long time; over 11-20 years, they rise into the stratosphere and act as greenhouse gases while they do; once they reach the stratosphere, they break down under UV radiation, releasing Cl and F and Br, accelerating the breakdown of ozone; CFC molecules can last in the stratosphere from 65-385 years, with each Cl able to break 100+ ozone mols.

• Halons and hydrobromofluorocarbons, methyl bromide, hydrogen chloride, and cleaning solvents (carbon tetrachloride, methyl chloroform, n-propyl bromide, and hexachlorobutadiene) are also ozone-depleting substances.

• Human Health/Structures
• Worse sunburns
• More eye cataracts and skin cancers
• Immune system suppression

• Food and Forests
• Reduced yields for some crops
• Reduced seafood supplies due to smaller phytoplankton populations
• Decreased forest productivity for UV-sensitive tree species

• Wildlife

• More eye cataracts in some species

• Shrinking populations of aquatic species sensitive to UV radiation

• Disruption of aquatic food webs due to shrinking phytoplankton populations

• Air Pollution and Climate Change
• Increased acid deposition
• Increased photochemical smog
• Degradation of outdoor painted surfaces, plastics, and building materials
• While in troposphere, CFCs act as greenhouse gas

• Prevention Approaches, like the above, work because:
• There was convincing and dramatic scientific evidence of a serious problem
• CFCs were produced by a small number of international companies - less corporate resistance to finding a solution
• The certainty that CFC sales would decline over a period of years because of government bans unleashed the economic/creative resources of the private sector to find suitable yet more profitable chemicals (Hydrofluorocarbons, which act as strong greenhouse gases)

• It’s working! By 2050, ozone levels will be near 1980 levels!!

20.2 - How and Why Is the Earth’s Climate Changing?

• Life depends on this, because it keeps the planet at an average temperature of 58˚F (15˚C).

• We focus on CO2, N2O, and CH4; N2O -> CO2 -> CH4 last the longest and N2O->CH4->CO2 have the largest atmospheric warming potential

• As global concentration of CO2/CH4 increases, the average global temperature increases too.

• (1) massive volcanic eruptions and impacts by meteors and asteroids that cooled the planet by injecting large amounts of debris into the atmosphere;

• (2)changes in solar input that can warm or cool the earth;

• (3)slight changes in the shape of the earth’s orbit around the sun from mostly round to more elliptical over a 100,000 year cycle;

• (4)slight changes in the tilt of the earth’s axis over a 41,000-year cycle;

• (5)slight changes in the earth’s wobbly orbit around the sun over a 20,000-year cycle (Factors 3, 4, and 5 are known Milankovitch cycles);

• (6)global air circulation patterns (see Figure 8.36);

• (7)changes in the sizes of areas of ice that reflect incoming solar energy and cool the atmosphere;

• (8)changes in concentrations of greenhouse gases;

• (9)occasional changes in ocean currents.

• Earth’s climate has fluctuated over the past 900k years, through alternating freezing and thawing periods (glacial/interglacial periods).

• Since 1975, atmospheric temperatures have been rising (10 warmest years since 1861 have taken place since 2005, glaciers are melting, average sea level has risen at exponential rate)

• Highest National Footprints: China US, India

• Highest Per Capita: US, Russia, Japan (US has emitted the more CO2 than any other country)

• Human activities have played an important role in the recent increase in the Earth’s atmospheric temperatures because:
• Human activities (mostly carbon-containing fossil fuel burning) have been adding CO2 to the atmosphere faster than the carbon cycle can remove it.
• Human activities have been cutting down large areas of the world’s forests faster than they can grow back naturally (through planting or succession

• Climate change is happening now

• Human activities (burning fossil fuels, clearing forests) play an important role in current climate change

• Average atmospheric temperatures are likely to increase and lead to more and faster climate change unless we act now.

• Immediate and sustained action to curb climate change is possible and affordable and would bring major benefits for human health and economies + the environment.

• Modern economies and lifestyles are built around burning fossil fuels that supply 90% of the world’s commercial energy and are largely responsible for: air pollution, climate change, and ocean acidification.

• This, however, is a) slowing down and b) causing ocean acidification while c) warming the oceans.

• Light colored aerosols (majority, from FF combustion) reflect incoming sunlight and cool the lower atmosphere. However, black carbon particles (emitted by industrial plants and coal burning, diesel exhaust, fires) warm the atmosphere.

• Aerosols/Soot Particles won’t affect climate change much because:
• Aerosols and soot fall back to Earth or are washed out of the lower atmosphere within weeks; CO2 remains for hundreds of years.
• We are reducing aerosol and soot emissions because of their harmful impacts on plants and humans.

20.3 - What Are the Likely Effects of a Warmer Atmosphere?

• Floods in low-lying coastal cities from a rise in sea levels

• More severe drought

• More intense and longer lasting heat waves

• More destructive storms and flooding

• Forest loss and increased forest fires

• Species extinction

• Atmospheric carbon level of 450 ppm

• Melting of all arctic summer sea ice

• Collapse and melting of the Greenland ice sheet

• Severe ocean acidification, collapse of phytoplankton populations, sharp drop in the ability of the oceans of absorb CO2

• Massive release of methane from thawing arctic permafrost and from the arctic seafloor

• collapse/melting of most of the Western Antarctic Ice sheet

• Severe shrinkage/collapse of Amazon Rain Forest

• Sea Ice and Mountain Glaciers are great storehouses of ice; many of these mountain glaciers have been shrinking wherever summer melting exceeds the winter snowpack (the addition of ice from precipitation in winter)
• Mountain glaciers have a vital role in the water cycle, storing water as ice during cold seasons and releasing it slowly to streams during warmer seasons for farmers and others to use. However, they’re melting faster and faster.

• Thawing permafrost is dangerous, as it can release methane (the arctic permafrost holds 2-4x as much carbon as all the carbon ever released by humans)

• The oceans have absorbed 90% of the extra heat added to the atmosphere, but as the oceans store more heat they expand (and land-based glaciers melt), rising the average sea level. This could do a lot of things:
• Degradation/destruction of ⅓+ of the world’s coastal estuaries, wetlands, coral reefs, and deltas where much of the world’s rice is grown.
• Disruption of many of the world’s coastal fisheries
• Flooding in large areas of low-lying countries
• flooding/erosion of low-lying barrier islands and gently sloping coastlines, especially in US coastal states.
• Submersion of low-lying islands in teh Indian Ocean, the Pacific Ocean, and the Caribbean Sea
• Flooding of some of the world’s largest coastal cities
• Saltwater contamination of freshwater coastal aquifers resulting in degraded supplies of groundwater used as a source of water for drinking and irrigation.

• Shell-building species and coral reefs grow more slowly as they can’t produce as much calcium carbonate. And if the pH gets high enough, their calcium carbonate will start dissolving, giving surviving species damaged or weakened shells/bones.

20.4 - How Can We Slow Climate Change?

• It’s a global problem

• It’s a long-term political issue

• The harmful/beneficial impact sof climate change aren’t spread evenly

• Proposed solutions are controversial (Ex: sharply reducing or phasing out fossil fuels)

• The projected temperature changes and effects are uncertain

• Cut fossil fuel use, especially coal

• Shift from coal to natural gas

• Repair leaky natural gas pipelines and facilities

• Improve energy efficiency

• Shift to renewable energy resources

• Reduce deforestation

• Use more sustainable agriculture and forestry

• Put a price on greenhouse gas emissions

• Sequester CO2 by planting trees, preserving forests and wetlands

• Sequester carbon in soil with biochar

• Sequester CO2 deep underground WITHOUT LEAKS

• Sequester CO2 in the deep ocean WITHOUT LEAKS

• Remove CO2 from smokestack and vehicle emissions

• Issues: they can remove and store only part of the CO2 emissions and at great cost, they don’t address the CO2 emissions from vehicles/food production/forest burning, require a lot of energy, and would have to remain sequestered forever (no leaks or death).

• Plus, they’re costly, risky, and not very effective cleanup solutions. Prevention approaches would be better and more effective.

• Regulate CO2 and Methane, as these air pollutants can harm public health and welfare.

• Phase out the most polluting coal-burning power plants over the next 50 years, replacing them with cleaner natural gas and renewable energy alternative, or nuclear power plants.

• Put a price on carbon emissions, phasing in taxes on each unit of CO2 or CH4 emitted.

• Use a cap-and-trade system, which would use the marketplace to help reduce emissions of CO2 and CH4 (gov caps emissions in a region, issues permits for certain levels of pollutants, and allows polluters to trade these permits in the marketplace)

• Phase out government subsidies and tax breaks for the fossil fuel industry and phase in subsidies and tax breaks for energy-efficient technologies and low-carbon renewable energy development.

• Work out agreements to finance/monitor efforts to reduce deforestation.

• Calculate your carbon footprint (there are several helpful websites)

• Drive a fuel-efficient car, walk, bike, carpool, and use mass transit

• Reduce garbage by reducing consumption, recycling, and reusing more items Use energy-efficient appliances and LED lightbulbs

• Wash clothes in warm or cold water and hang them up to dry

• Close window curtains to keep heat in or out

• Use a low-flow showerhead

• Eat less meat or no meat

• Heavily insulate your house and seal all air leaks

• Use energy-efficient windows

• Set your hot-water heater to 49 degrees C

• Plant trees and buy from businesses working to reduce their emissions

20.5 - How Can We Adapt to Climate Change?

• Expanding mangrove forests as buffers against increasing storm surges, building shelters on high ground and planting trees on slopes

• Seawall design and construction in the face of projected higher levels of precipitation and rising sea levels (flood control barriers)

• Considerable scientific evidence indicates that human activities are playing an important role in warming the earth’s atmosphere, and that this is likely to lead to significant climate disruption during this century that could have severe and long-lasting harmful consequences.

• Reducing the projected harmful effects of rapid climate change during this century requires emergency action to increase energy efficiency, sharply reduce greenhouse gas emissions, and rely more on renewable energy resources.

• While we can prepare for some climate change that is now inevitable, we could realize important economic, ecological, and health benefits by drastically reducing greenhouse gas emissions with the goal of slowing climate change.