AP environmental science college board review

Tragedy of the commons

this happens when people overuse a shared, limited resources out of self-interest, which eventually harms everyone.

Because these resources are shared and no one person “owns” them, there’s little accountability or incentive to conserve.

Examples commons

1. Fisheries and ocean ecosystems

2. Freshwater supplies (aquifers, rivers)

3. The atmosphere (air quality, greenhouse gases)

4. public lands (like parks and rangelands)

5. Game animals or wild populations

Why does tragedy of the commons happen

1. Individual users act rationally for themselves, thinking: “If I don’t take it, someone else will.”

2. Each person or group receives all the benefit, but the cost of depletion is shared among everyone.

3. These resources are often unmanaged or poorly regulated.

Example of tragedy of the commons

1. Oceans: Overfishing, plastic pollution, and coral reef decline

2. Air: CO₂ and greenhouse gases from transportation and industry → climate change

3. Freshwater: Drawing too much water from aquifers (like the Ogallala) → depletion

4. Forests: Unsustainable timber harvest on public land → habitat loss & erosion

5. National parks & BLM land: Overuse from tourism or vehicle traffic leads to degradation

6. Game species: Overhunting leads to population collapse (e.g., North American bison)

7. Public transport & infrastructure: Littering or vandalism because it’s “not yours”

Solutions to tragedy of the commons

• Regulation (laws & rules)

  • Examples: fishing quotas, emission standards, protected areas

  • Works best when governments or institutions enforce rules

• Privatization

  • Turning shared land or resources into private property increases personal responsibility

  • Can work with land, but harder for shared global resources like air or oceans

• Education & Peer Pressure

  • Informing people about impacts of overuse

  • Cultural or community pressure to act sustainably can reduce overuse (especially locally)

• Permits, licensing, or user fees

  • Limits access so only a certain number of users can use it (e.g., hunting licenses, water rights)

• International Agreements

  • Needed for commons like the ocean or atmosphere

  • Examples: Paris Agreement (climate), CITES (endangered species)

Clearcutting

A logging method where all or most of the trees in an area are removed at once.

Main goal is a quick and complete timber harvest, especially used in commercial forestry and it is favored economically because it maximized short term profit, easier access and simpler operations for loggers, and efficient replanting in Monoculture.

Clearcutting impacts on soil and land

• Soil erosion increases:

  • Tree roots normally hold soil in place → without them, soil washes away easily.

• Nutrient depletion & compaction:

  • Heavy machinery and root loss reduce soil health.

• Pesticide Use:

  • Often used to clear undergrowth or invasive plants before logging

  • Toxic chemicals further degrade soil and harm local species

Clearcutting impacts on water

• Stream temperature rises:

  • No tree canopy = more direct sunlight hitting water

  • Can stress or kill temperature-sensitive aquatic organisms

• Water pollution & flooding:

  • More sediment runoff enters rivers/streams

  • Without tree absorption and slowed runoff, water flows faster = flood risk

Clear cutting impacts on Air quality

• Forests filter more than carbon:

  • Many trees also absorb pollutants like ozone, sulfur dioxide, and particulate matter

  • Losing forests means less natural air filtration and more airborne pollution

Clearcutting impacts on Habitats

• Entire ecosystems are lost with clearcutting:

  • Nesting sites, food sources, and shelter all vanish

• Habitat loss often leads to:

  • Local species extinction

  • Reduced biodiversity

  • Loss of ecological balance

Selective cutting

is an alternative to clearcutting that lower environmental damage and it is cutting where only mature or specific trees are removed, preserving canopy and root systems.

Group/patch cutting

It is an alternative to clearcutting that lowers environmental damage and it is cutting where small, contains areas are harvested to limited erosion and density loss.

By removing the existing canopy, this created an open environment that allows sunlight to reach the forest floor, promoting the growth of species that require full sun. It can create clearing that are suitable for certiant wildlife (habitat creation), and it can eliminate or reduce the spread of forest disease and insects.

Strip cutting

It is an alternative to clearcutting and it is where narrow rows or strips are cut with untouched forest between them.

It aids in maintaining more habitat for wildlife, as it leaves uncut strips of trees and it can enhance biodiversity support a wider range of species that rely on different habits. Reduce soil erosion, and easier for forest regrowth because tree along the edges can seed into the cut areas.

Green revolution

This was a shift in global agriculture, starting in the mid-20th century, that introduced new technologies to dramatically boost food production.

Main goal: Feed a rapidly growing population by increasing crop yields using technology and science

tools in the green revolution

• Selective breeding/high-yield crop varieties

• Genetically modified organisms (GMOs)

• Synthetic fertilizers

• Advanced irrigation systems

• Chemical pesticides and herbicides

• Mechanization

Point sources

is a category of water pollution and it is pollution that enters the environment from a single source and I'd clearly identified.

The use of categories is to differentiate the sources of contamination in order to manage them effectively.

The EPA set water quality standards, and these classification help determine protection strategies.

Ground and surface waters can be impacted by ______ and _______ spruce pollution.

Example of point sources.

1. Wastewater treatment plants (facilities that process wastewater from homes and business to remove pollutants before releasing it back into the environment)

2. Electronic or automobile manufactures

3. Paper or pulp mills (are industrial facilities where plant fibers, like wood, are processed into pul, which is used to make paper. And these can release pollutants into the air and water)

4. Oil refineries (a large industrial plant that transforms raw crude oil into various usable petroleum products.)

5. concentrated animal feeding operations

6. leaking underground gasoline storage tanks

Clear Water Act

It is a way to control point sources pollution and it requires industries of point sources to get a permit from the state and/or EPA before they can discharge any effluent (waste) into a body of water.

THe point sources will also have to use effective technologies to rest the effluent (wste) before it can be discharged.

Nonpoint source pollution

is a category of water pollution and it is pollution that cannot be traced back to a single point or property… not from a single pipe.

Contributions of contaminants come from many sources accumulating over a wide area and eventually reaching a level that impairs water quality.

Examples of Nonpoint source pollution

1. Agricultural and residential areas can have excess chemicals such as: fertilizers, herbicides, insecticides

2. Water from rain, snowmelt, and irrigation running of parking lots, roads, lawns in urban/suburban areas can be a source of: oil, greases, and toxic chemicals.

3. Sediment, which is one of the most significant nonpoint sources pollutants in the United States, is soil particles made of sand, gravel, and clay, is from improperly managed: Construction sites, crop and forest lands, eroding stream banks.

How to manage nonpoint sources

________ ______ are not regulated through permitting but managed through programs that encourage partnerships between private landowners and business with local and states government working together.

Coral reefs

Are critical ecosystems in the oceans and cover less than 1% of the area but support 25% of marine species.

They are made up of animals that live symbiotically with algae that photosynthesize.

Bottom trawling

Is a destructive fishing practice to coral reefs and it is scraping nets along the ocean floor which breaks and crushes coral.

Marine debris

Is a destructive fishing practice to coral reefs and it is debris that it is left in the ocean like unattended nets, traps, and monofilament fishing line that can damage and injure reefs and reef-dependent organisms like young fish.

Overfishing

Is a destructive fishing practice to coral reefs and it is over removing fish, especially herbivores, which help maintain healthy algae populations in reef ecosystems.

Cyanide fishing

It is a destructive fishing practice to coral reefs and it is when sodium cyanide is poured over an area to stun fish so they are easier to catch for the aquarium and restaurant trade. This poisons corals.

Sedimentation threatens coral

Sedimentation, soil particles of rock, clay, and sand, can bury corals, blocking the sunlight needed by the symbiont so no photosynthesis can occur, which results in the death of the coral.

Optimal range of tolerance

Within this range reproduction, growth, and maintenance of homeostasis it at its best.

And this is a set of environmental condition a certain species is present in.

Zones of physiological stress

Are the low and high zones in the range of tolerance that inhibits the success of the organism.

Coral bleaching

High temperatures causes a process called ______ _________ to occur in coral reefs.

This is where coral expels the symbiont out of its cells, resulting in a loss of food supply and the color from the chlorophyll pigment of the algae

Dissolved oxygen.

The amount of oxygen gas that is present in water. It’s essential for the survival or aquatic organisms, as they use dissolved oxygen to breathe. And the range of tolerance applied to ______ ______ (DO) for species living in aquif environments, furthermore DO is usually measured in ppm.

Though warm water does not hold as much dissolved oxygen as colder water as it is less dense and evaporates more.

Oxygen sag curve

is a plot of dissolved oxygen levels versus distance from a source of pollution with excess nutrients.

Pay attention to low oxygen tolerant species (can withstand low oxygen levels) and Low oxygen intolerant species (can’t stand low oxygen levels)

This first zone all the way to the left would be the clean zone where it is biologically diverse and there is low environmental impacts, evident in how there is high dissolved oxygen and the biological demand for oxygen is low.

Then for the next zone, which is decomposing, this is where there is a pollution event takes place, which pours nutrients into the water and causes algae bloom which either deplete the water of oxygen or when they are decomposed, the decomposers take in large amount of oxygen to decompose them. This leads to low dissolved oxygen context, and therefore a high biological demand, pared with low biological diversity.

The third zone, after the decomposing zone, would be the septic zone where there are still impacts of the pollution, evident in the low dissolved oxygen and high biological demand. Though in this area there is slight recovery.

After the septic zone, there would be the recovery zone where dissolved oxygen content is rising and the biological demand for oxygen is decreasing.

The last, zone, further away from a pollution site and after the recovery zone would be the clean zone again.

Oil spills impact wildlife

Oil that floats on the surface of the water can coat the feather of birds, robbing them of both insulation and the ability to fly.

The fur of marine mammal es like seals and sea otter can become saturated with oil, inhibition their waterproofing and ability to maintain their body temperature.

They can ingest the hydrocarbons as they try to groom the oil from their fur, and all organism that ingest or inhale hydrocarbons die from poisoning.

Some component of oil sinks to the ocean floor, and these oil blobs can stay at the bottom for a long time as they are not broken up by wave and wind action on the ocean surface. So organism living at the bottom are at risk of death through oil ingestion and submersion.

Coastal economies impact by oil spills.

Oil spills damage fishers for years as the growth and development of all fish species and the plankton that supports them is impacted.

With both the Exxon spill and the BP Deep water Horizon spill, oil that washed up on beaches impacted tourism, real estate, and fishing industries.

With the deep water Horizon spill losses in the billion of dollar was felt in Mississippi, Louisiana, Florida, and Alabama.

How producers and consumers are impacted by sedimentation

How producers and consumers are impacted by sedimentation:

Sediment suspended in the water column can affect primary producers (plants) because light infiltration is reduced. This impacts the ability of plants to photosynthesize and add oxygen to the water.

Predator that use vision as their primary sense for hunting are also impacted.

As the sediment settles, it can disrupt the eggs and large of aquatic species, like fish, insects, and mollusks.

Heavy metals that can be found in drinking water

1. Lead

2. Mercury

3. Arsenic

4. Copper

5. Cadmium

6. Chromium

How mining companies can release heavy metals into drinking water:

How mining companies can lease heavy metals into drinking water:

Mining companies often use acid to release metals from ore. This acid mine drainage can be a point sources pollution for surface water and groundwater.

Other industries, like smelting, chemical production, wastewater, and fossil fuel combustion can also release heavy metals into the environment.

Heavy metals in drinking water health cost

Heavy metals in drinking water health cost:

Heavy metals in drinking water can cause cancer, organ damage, and neurological issues.

Mercury cases neurological damage:

Mercury causes neurological damage:

Mercury poisoning is most often through eating fish or other aquatic organisms.

Mercury can be used in many industrial processes and end up in wastewater (used water that has been contaminated by household, industrial, or commercial use, and need treatment to remove pollutants before being released back into the environment). There it is converted by bacteria into, methylmercury, which is toxic and will bioaccumulate in organisms and biomagnify (toxic substance move up the food chain) in the food chain.

The impacts it has on health include:

1. Deteriorates nervous system

2. Impairs hearing, speech, vision and gait (the walking patterns in humans)

3. Cause involuntary muscle movements

4. Corrodes (to be gradually destroyed or weakened) skin and mucous membranes

5. Causin chewing and swallowing to become difficult.

Plastic waster threat to wildlife

Plastic waste threat to wildlife:

Plastic waste in waterways and he oceans has increased

ingestion of this litter has no nutritional value and can also block the digestive system, leading to painful starvation.

It can entalge the wildlife and lead to death by suffocation

Microplastic contribution to toxin

Microplastic contribution to toxin:

Microplastics, tiny degraded plastic particles and fibers can contribute toxins to the environment in two ways:

1. The releases of endocrine-disrupting chemicals like BPA added to plastic polymers when they are produced.

2. Chemicals like Pesticides cling to the tiny particles and are then ingested by plankton and other organisms.

Endocrine disruptors found in synthetic and natural chemicals

Endocrine disruptors found in synthetic and natural chemicals:

Endocrine disruptors can be synthetic chemicals used as:

1. industrial solvents/lubricants and their byproducts:

   1. Polychlorinated biphenyls (PCBs)

   2. Polybrominated biphenyls (PBBs)

   3. dioxins

2. Plastics and Plasticizers

   1. bisphenol A (BPA)

   2. phthalates

3. Pesticides and fungicides

4. Pharmaceuticals

They can be found as natural chemicals in food:

1. Phytoestrogens found in soy

Some exposure can be from spill or leaching of improperly dispose of toxic waste. And some exposure are more persistent as the chemicals are in the soil, water, and air as well as material in our homes and workplaces.

Endocrine system

A network of glands that produce and releases hormones directly into the bloodstream to regulate various bodily functions.

And endocrine disruptors are any chemical that interferes with the production, transports, metabolism, or function of hormones in bodies.

Hormones are associated with homeostasis, reproduction, and development. Hormones you might recognize:

1. Estrogen

2. testerone

3. insulin

4. serotonin

5. norepinephrine

How endocrine disruptors impact cells

How endocrine disruption impact cells:

Endocrine disruption can mimic the structure of a signaling chemical that would normally bind with a cell receptor to trigger a cellular response.

Endocrine disruption can block the signal from reaching the receptor or block the transduction cascade.

Consequences include reproductive abnormalities, birth and developmental defects, or possible behavior changes.

Endocrine disruption impact on aquatic systems

Endocrine disrupting chemicals enter waterways and bioaccumulate in organism and biomagnify in the food chains so that top-level consumers are most impacted.

People, predatory fish and amphibians that consume a high number of prey with endocrine disruption in their body will accumulate high elves of the chemicals.

This can cause eggs, not sperm present in the gonads of a male fish species.

In humans, low sperm counts have been recorded in communities with high pesticide use.

Developmental abnormalities in amphibians and fish in the wild have been recorded by investigators.

Wetlands

Are lands that are defined as having water covering the soil or is near the surface of the soil for all, or most of, the year.

Costal (or tidal) _______ have fluctuant saliny and water levels as they are influenced by the tides.

Inland (or notidal) ___________ are along rivers and floodplains, in depression or low-lying areas near lakes and ponds and often have a seasonal nature to them.

How wetlands improve water quality.

How wetlands improve water quality:

Water can move slowly in wetlands, giving sediment, nutrients, and pollutants time to drop out of suspension in the water column to the bottom of the wetland.

Excess nutrients from leaking septic systems (one site wastewater treatment systems), agricultural runoff, and municipal sewage, can be taken up by plant roots for use in growth or further broken down by microbes in wetland soils.

Pollutants can stick to soil particles or be taken up by plants.

Much of the sediment, nutrient, and pollutant load is reduced as water moves out of wetlands because of this filtering capacity.

How wetlands provide flood control

How wetlands provide flood control:

Wetlands act like sponges, holding water in place and releasing it slowly.

By slowing the movement of water, flood heights are reduced along with their erosive powers.

Coastal shorelines are protected and stabilized.

How wetlands maintain water flow during dry periods

How wetlands maintain water flow during dry periods:

Groundwater is recharged as water is held in wetland soils.

This also helps maintain surface water flows during dry seasons.

How wetlands increase biological productivity:

How wetlands increase biological productivity:

Wetlands are some of the most productive ecosystems on the planet because shallow water and plenty of plants allow for diverse habitat for animals and birds.

Nutrient-rich soils enhance plant growth which in turn provides food for diverse and abundant species.

Mangroves

_______ are a type of particularly productive and valuable type of coastal wetland.

They are dominated by ______ trees, which are salt-tolerant plants adapted to growing in saline or brackish water along coastlines.

In addition to living in a variety of saltwater conditions and providing shelter and food for a host of species, ______ can absorb four times the carbon dioxide that upland forests can.

Threats to wetlands

Development of commercial properties like restaurants, malls, airports, business offices, gas stations, etc. can all be damaging to wetlands.

Development can include filling in wetlands to build access roads, parking areas, or place utilities.

Construction can increase sedimentation, destroy habitat, and redirect water flow.

In the United States, development in wetlands is highly regulated through the Wetlands Protection and Restoration Act. Many states and tribal governments also have regulations for wetland protection.

Dam construction restricts and reduces water flowing into wetlands by disconnecting rivers from their floodplains and wetland areas.

The natural downstream flow of sediment that creates deltas and builds up estuaries along coasts is reduced.

Migration of fish and other species can be impacted.

Excess nutrients and pollutants from agriculture and industrial operation can impact wetlands, (example of CAFO/ concentrated animal feeding operation. These operation raise and house millions of animals)

Waste management is critical

Waste management is critical:

For example for a manure lagoon found at concentrated animal feeding operations (CAFOs) use heavy plastic lining and thick-walled embankment are to prevent leaked of nutrients and bacteria like e.coli.

Management of manure, as well as, other agricultural practices like Pesticides and insecticides use and soil management can help protect wetlands, surface and groundwater.

Eutrophication

Is when a waterway receive excess nutrients, this causes massive algae blooms plants and cyanobacteria, which once decomposed cause the oxygen to become depleted due to the amount of oxygen that is required for the massive amount of algae to be decomposed.

In lake Erie, toxic algae can threaten the drinking water for 11 million people in southwest Ohio and impact tourism, fishing, and recreation.

In most cases eutrophication is caused by the excess nutrient nitrogen from agriculture or urban runoff but also from phosphate in detergents.

Sources of cultural eutrophication

Sources of cultural eutrophication:

1. Excess fertilizers from farm fields

2. Sewage from wastewater treatment

3. Nitrogen from animal manure

4. Phosphate from detergents

These material are washed by rain, melting snow, and irrigation into streams, ponds, and lakes.

Eutrophic waterway

________ waterway is a water system that has high levels of algae as a result of excess nutrients.

It has high plant and algae populations though low dissolved oxygen.

This can happen due to things like a storm even washing fertilized into an aquatic system.

Aquatic organisms that can’t tolerate low oxygen levels will leave. If they can’t leave, they die. This adds more waste to be digested by oxygen-consuming microbes.

These conditions would create widespread hypoxia (condition where there is an insufficient amount of oxygen in the body’s tissue or organs) which would categorized the area as a dead zone.

Oligotrophic waterway

an __________ waterway has very low amounts of nutrients.

It has stable plant and algae population and high dissolved oxygen.

Thermal pollution

Is a rise or drop in the temperature of a natural body caused by human activities. This change in temperature can disrupt aquatic ecosystems by affecting the amount of dissolved oxygen impacting the tolerance of various species.

Sources of thermal pollution

When heated water is discharged into bodies of water, it is consider thermal pollution.

Power and industrial plants draw in water to cool machinery or products. They tend to discharge the heated water back into a water source.

Other sources include:

1. Soil erosion (when soil washes into a body, it makes the water murky, causing it to absorb more sunlight and heat up)

2. Deforestation/ shade reduction

3. Discharge from wastewater treatment

4. urban ruoff (carrying heated water from urban surfaces like roads and parking lots into waterways. This heated water lowers the dissolved oxygen in the water, harming aquatic life and ecosystems)

Impacts of thermal pollution

Slight variations in temperature can impact survival or eggs or leave of fish and aquatic insects that have narrow ranges of tolerance.

Die-offs can occur when dissolved oxygen levels are too low .

Feeding, breeding, and migration behaviors can also be altered.

Thermal refuge

This is aquatic species response to thermal pollution:

During winter months, when the ocean temperature can dip below 70 degrees, manatees seek out these warm water discharge areas as a place to feed and rest for the season.

Historically, manatees used natural springs to overwinter. These have disappeared due to development and agriculture pressures.

How is it that the lower dissolved oxygen levels aren’t an issue for the manatees (manatees are relatively tolerant due to their need to surface frequently to breathe).

Persistent organic pollutants

Are synthetic (not naturally occurring, it made by humans), carbon-based chemicals that persist in the environment for long periods, resist degradation, and accumulate in organism, potentially causing harm to both humans health and ecosystems.

They are often by-products of industrial process and can travel long distances through air and water systems (including wind and global patterns), impacting areas far from where they were released.

They are:

1. Persistent

2. Organic (because they are carbon-based)

   1. Often in rings, with chlorine attached to the outside of ring (5-carbon ring)

3. Synthetic

4. Nopolar (don’t have a positive or negative end, meaning they don’t attract or repel water, so they are not soluble in water and tend to be more soluble in other nonpolar solvents)

5. fat-soluble

Example of Persistent organic pollutants

1. Dichloro-diphenyl-trichloroethane

   1. Insecticide

   2. Colorless crystal

   3. Banned for use in the United States

2. Polychlorinated biphenyl (PCBs)

   1. industrial fluid

   2. yellow liquid

   3. Banned for use in United States

And they were used to monitor or to reduce agricultural pests and also vectors for diseases—-everything from mosquitoes to lice—though it was banned due to the persistence aspect.

Though it is used in other countries to reduce diseases like malaria

Response to Persistent organic pollution in water and soil

1. Clear water Act was passed

2. Safe drinking water act was passed

3. RCRA —- Resource Conservation and Recovery act was passed

4. CERCLA —- Comprehensive environmental response, compensation and Liability act was based.

5. Stockholm Convention (international treaty that banned or reduce the manufacturer of these persistent organic pollutants)

Bioaccumulation

______________ is the selective absorption and concentration of elements or compounds by cells in a living organisms, most commonly fat-soluble compounds.

Biomagnification

The process where toxins and pollutants accumulate in organisms at higher trophic levels (e.g., predators) in a food chain, resulting in higher concentrations than in lower levels.

Substances that bioaccumulate

1. DDT (Dichloro-diphenyl-trichloroethane), which is a persistent organic pollutant.

2. Methylmercury (which is a heavy metal and is persistent)

3. PCB (Polychlorinated biphenyl), which is a persistent organic pollutant and endocrine disruptor.

Impacts of biomagnification on Apex predators

Impacts of biomagnification on Apex predators:

Secondary and tertiary consumers, like eagles, are impacted by the overuse of persistent organic pollutants, specifically DDT, when they reach a certain threshold concentration (from bioaccumulation), it inhibits the processing of calcium in the bodies of apex predators.

Eggshells are made, among other things, of calcium, so when these birds do lay their eggs, the’re very thin. So what happens when these eggshell are laid is either, when they hit the nest, they will break open. Or the active brooding, keeping that egg warm, will end up crushing the egg.

This will have the impact of lowering the population due to the fact that there eggs are not viable enough to be carried into full term growth.

Pollutant can also cause deformity in the chicks themselves, which decreases the chance of survival for the chicks chicks

Ozone layer

The ______ layer is a region in Earth’s stratosphere that contains a high concentration of ______ (O3), which acts as a shield against harmful ultraviolet (UV) radiation from the sun, and it is naturally occurring and approximately 15 to 35 kilometer above the Earth’s surface.

This layer is essential for protecting life on Earth by absorbing most of the sun’s UV-B and UVC radiation.

Though the ______ (03) from photochemical smog; is located in the troposphere and is not naturally occurring as it is formed from greenhouse gases/ greenhouse effect.

Different types of ultraviolet radiation from the sun.

Different types of ultraviolet radiation from the sun:

1. UV-C: is the strongest and most energetic type of ultraviolet radiation and is comes in about 180 to 280 nanometers. And 100% of it is absorbed by the ozone layer.

2. UV-B: Is the second strongest ultraviolet radiation and it comes in between 280 and 315 nanometers. And 95% of it is absorbed by the ozone layer.

3. UV-A: is the weakest type of ultraviolet radiation and it comes in about 215 and 400 nanometers. And 5% of it is absorbed by the ozone layer.

How UV-C is blocked by the ozone layer

1. Once UV light that is below 240 nm comes in contact with the ozone layer, where UV-C comes in about 180-280 nanometers, it will disrupt the bond of the oxygen molecule present in the ozone layer, which will cause it to break and form 2 oxygen atoms.

2. These oxygen atoms (0) will quickly attach to natural oxygen (02) to form ozone (03)

3. Peak ozone (03) generation occurs at 185 nm wavelength of UV light.

How UV-B is blocked by the ozone layer

1. Once UV light that is between 240-315 nm comes in contact with the ozone layer, where UV-B comes in between 280 to 315 nanometers, it will disrupt the bond of the ozone molecule (O3) and convert this ozone back into oxygen (02). Which leaves one oxygen atom present (0)

2. The oxygen atom present (0) will find another sing oxygen atom (0) to form another oxygen molecule (02)

3. Peak ozone destruction occurs at 254 NM wavelength of UV light.

How the antarctic impacts the ozone layer:

how the antarctic impacts the ozone layer:

1. Antarctic winters can create stratospheric clouds full of ice crystals (so clouds that rise to the stratosphere and are full of ice crystals)

2. The ice crystals melt in the beginning of the spring (which happens in September and October since it is in the southern hemisphere)

3. Chemical reactions happening in the stratosphere convert the less reactive chlorine, from the ice crystals, to a more reactive form.

4. The more reactive form of chlorine degrades ozone into atmospheric oxygen (o2)

5. This causes the ozone layer to thin.

Chlorofluorocarbons (CFCs)

Is a chemical that was developed as a refrigerant/coolant, so it cools refrigerators.

It was also used as a propellant, so a substance that provides the force needed to move something else forward.

And lastly, it was used in some types of plastics.

It was a stable compound, meaning it doesn’t easily break down or react in the environment, and it is an inert gas, meaning it is a gas that doesn't readily react with other substance under normal conditions. Furthermore, if it does escape it will rise into the troposphere and eventually the stratosphere, as it also contribute to the greenhouse effect.

Chlorofluorocarbon impact on the stratosphere

When CFCs become present in the ozone layer in the stratosphere the chlorine atom (Cl) of the CFCs atom is disconnected with the CFCs molecule as it is pulled to an ozone molecule (o3)

Then the chlorine atom (Cl) binds with the ozone molecule (O3) to form ClO which pushes out an oxygen molecule (O2).

Then ClO will go to bind with an oxygen atom (0) where it will have the byproducts of becoming a single chlorine atom (Cl), and the oxygen atom from the previous ClO, will bind with the oxygen atom to become an oxygen molecule (o2).

Then the single chlorine (Cl), will repeat the whole process by starting with combing with an ozone molecule (O3)

This break down of ozone from this process into an oxygen molecule has the impact of thinking the ozone layer.

The thinning of the ozone layer will have the impact of allowing more UV-C and UV-B to pass through this layer and reach the ground of earth.

Effect of ozone depletion

The impact of ozone depletion (where there is thinning of ozone layers, especially at poles), has the impact of disruption of terrestrial photosynthesis. This occurs cause the increased UV-B radiation can damage plant tissues, affecting leaf structure and reducing the ability of plants to effectively perform photosynthesis, and it can damage their cells. This hinders photosynthesis.

It can also cause disruption of photosynthesis by phytoplankton by the increased UV radiation damaging their DNA and cellular structures, ultimately reducing their growth and productivity.

The impact this has on the producers can cause a disruption of food chains. webs.

Furthermore it impacts populations of some organism like amphibians because amphibians lay their eggs in water so they don’t have any shells on them so that UV light can directly interact with the egg. So the increased UV causes mutations in the eggs that prevent the egg from hatching, or surviving to adulthood.

In humans the increased exposure to UV can cause mutation in the skin that can cause skin cancer. Furthermore cataracts, which are a clouding of the lens of the eye (which is typically clear, can be a product of excessive exposure to UV light. This can lead to blurring or complete blindness that is irreversible.

Montreal Protocol

Was an International treaties that arose when two chemist found the impacts of CFCs in the thinning of the ozone layer.

This international treaty led everybody to agree that CFCs were thinning the ozone layer and it is a prevailing problem that needs to be prevented to help combat skin cancer and cataracts in humans.

So in this treaty started to phase out the use of chlorofluorocarbons and also their manufacture, which was done in 1987, though the United States started phasing these out in 1994.

Though because CFCs are stable it is going to take a long time for them to phase back decades for the ozone layer to be fully repaired.

HFCs replace CFs.

Due to the Montel protecall, which banned the use of CFCs, they have been replaced with hydrofluorocarbons (HFCs) which is a molecule that doesn't contain chlorine, and preformed that same functions as CFCs.

Though the drawbacks is they are a greenhouse gas and they contribute to the greenhouse gas effect, and these HFC’s include:

1. Fluoroform (HFC-23)

2. Difluoromethane (HFC-32)

3. Fluoromethane (HFC-41)

The greenhouse effect

This takes place in the troposphere, which is the closest atmospheric level to the ground and where we have most of our weather.

First solar radiation that has passed the ozone layer, some of it is absorbed by terrestrial soil, bodies of water, and some of It is reflected back up into the atmosphere.

Though after it has been absorbed by the Earth's ground some of it is radiated back into the atmosphere as infrared radiation, or heat.

Some of that reflected infrared radiation is absorbed by greenhouse gases, and turned into longer infrared radiation, which is radiated back into the atmosphere and back down to earth (This is called the __________ effect, which is the naturally warming of the earth).

Key Note: 78% of the atmosphere is made of nitrogen, 21% of it is oxygen, and in that remaining 1% a fraction of that 1% are the presence of greenhouse gases that make life possible on this planet.

Greenhouse gases

These gases include:

1. Carbon dioxide — CO2 —- these are naturally occurring but can be emphasized by human activities

2. Methane — CH4 —— these are naturally occurring but can be emphasized by human activities

3. Water Vapor — H20 —- these are naturally occurring but can be emphasized by human activities

4. Nitrous oxide — N20 —- these are naturally occurring but can be emphasized by human activities

5. Chlorofluorocarbons (CFCs) — CF2CL2 — these are human made

6. Hydrofluorocarbons (HFCs) — these are human made

7. Tropospheric ozone — O3 — these are human made.

Sources of Greenhouse gases from humans

Sources of Greenhouses gases from humans:

1. For Carbon dioxide:

   1. Transportation 34%

   2. Electricity 32%

   3. Industry 15%

   4. Residential & Commercial 11%

   5. Other (Non-fossil fuel combustion) 7&

2. For Methane:

   1. Enteric Fermentation (where microbes in the digestive tract of ruminate animals, like cattle and sheep, break down food and produce methane as a byproduct)

   2. Natural Gas and Petroleum systems 28%

   3. Landfills 17% (when organic waste decomposes under anaerobic conditions/without oxygen this release methane)

   4. Manure Management 10% (anaerobic condition in manure storage allow bacteria to produce methane as a byproduct)

   5. Coal Mining 8%

   6. other 9%

3. For Nitrous Oxide:

   1. Agriculture and soil management 78% (can be emitted through synthetic fertilizers)

4. For Fluorinated Gas (CFCs and HFCs)

   1. Substitution of ozone depleting substances like coolants

5. For Tropospheric ozone (03)

   1. This is present in troposphere and it is a secondary pollutant that is formed as a part of the chemical reactions that from photochemical smog in the troposphere.

Water vapor as a greenhouse gas

Water vapor, which is naturally occurring, becomes present in the atmosphere through evaporation. And the time that it builds up in the atmosphere is not signification was it condense, and forms precipitation.

Due to this its resident times, which is the time that water vapor is present in the troposphere, is relatively short. Which reinforce the idea that water vapor is not an impactful greenhouse gas.

Global warming potentials

A greenhouse ______ _______ ______ is based on the amount of energy that it re-radiates and it residence time in the atmosphere.

Carbon dioxide is used as the standard to be compared to other greenhouse gases because it has a ______ ______ _____ of 1.

Though water vapor is not considered on this because its resident time in the atmosphere is so low.

Concentration of greenhouse gases.

Concentration of greenhouse gases in the atmosphere is a key factor to look at in determining what greenhouses gas needs to be combated. And the most concentrated greenhouses gas in the atmosphere would be Carbon dioxide, which has about 81% concentration, despite its GWP of 1.

The greenhouse effect amplifies

Due to the increase of the greenhouses gases present in the troposphere it has caused the greenhouse effect to amplife, meaning there is more heat that is being re-radiated back into earth due to the growing abundance of greenhouses gases.

This has the impact of rising the global temperatures over time. (climate change)

Sea levels rise

Is an impact of climate change and this is where land ice (ex— continental glaciers, ice sheets) melts, adding to the volume of water in the ocean.

Due to ice having a high albedo, which is refleacity of UV, it reflects a lot of the sun’s radiation which provides cooling effects. Though as more land is exposed as the ice melts, more UV is absorbed which releases heats, due to land having a lower albedo, so it reflects less of the Sun’s radiation.

Thermal expansion of the ocean happens, due to warming from climate change, which increase the volume of the ocean, due to the fact that as water heats up it expands.

This has the impact of increasing flooding, hurricanes, and typhoons. (due to warmer water providing more energy for these storms to develop and intensify) And increasing the marine environment.

Diseas vectors expand their range

Disease vectors, like mosquitoes and ticks, are able to expand their living range as the Earth's climates increase in warmth. This occurrs because more places fit their ecological niches, for a warm environment (as they becomes warmer due to climate change), which allows them to expanded to new places that can now support their survival.

This can have an impact of spreading of disease to new places, that are carried by these diseases vectors.

How climate change impacts populations

How climate change impacts populations:

1. Habitat destruction (like saltwater intrusion of inland wetlands)

2. Loss of food source (organism die out due to increase temperatures)

3. Timing of food source availability changes (vegetation will sprout early due to the early coming of spring, marked by warmer temperatures, though delys will happen as migration patterns of animals like birds stay the same)

4. New salinity beyond range of tolerance (can cause things like the calcium carbonate of organisms to dissolve)

5. Increased storm intensity (warm water feeds the intensity of storms like typhoons and hurricanes)

6. Increased possibility of fire (more arid conditions due to increased evaporation)

7. Impacted annual group behaviors; timing of migration, hibernation.

How climate change impacts human populations.

Exposure impacts on humans populations due to climate change:

1. Extreme heat

2. Poor air quality (increasing temperatures, lead to more ozone formation, which is a major component of smog, and increased wildfire activity)

3. Reduced food and water quality (by altering environmental conditions, like changes in perception and temperatures, which can damage crops)

4. Changes in infectious agents

5. population displacement

Health outcomes due to exposure impacts from climate change:

1. Heat-related illness

2. Cardiopulmonary illness (by worsening air pollution and extreme temperatures causing impacts on both the heart and lungs)

3. Food-water-and vector borne disease

4. mental health consequences and stress

Populations that are more vulnerable to impacts of climate change:

Populations that are more vulnerable to impacts of climate change:

1. Low-income populations (they have fewer resources to cope with and adapt to climate-related hazards. They may live in areas that lack access to essential services like clean water and healthcare, and rely on resources that are affected by climate change)

2. Occupational groups (due to increased exposure to extreme weather events and hazers, particularly those working outdoors or in high-risk areas)

3. People in certain locations

4. Pregnant women

5. People with pre-existing medical conditions

6. children

7. older adults

8. people with disabilities

9. indigenous people (because they often rely heavily on natural resources for their livelihoods and well-being, and are frequently marginalized and lack access to essential resources and infrastructure)

Ice Historical records of climate change

There is data for about the past 800,000 years up till present that tells us about regular periods of warming and cooling, and regular periods of carbon dioxide increases and decreases in concentration in our atmosphere.

One way we get this information from is ice cores, where you drill down into the ice and pull out a long cylinder of ice and use that to get data.

As there are air bubbles present, which can be extracted and measured by how much carbon dioxide is there. And the darker lines tell about different melting times, which gives evidence on warming and cooling.

Volcanic records for climate change.

We can pull data from volcano ash which tells us the max and min values of the warming and cooling, and different concentration in the atmosphere.

It can also display how gradually those changes happens over periods of time

Changes in air circulation from climate change:

Changes in air circulation from climate change:

Convection currents, like the Hadley cells, could change in size which would cause disruptions in the movements of of warm, cool, wet, and dry winds as the perception and temperature are impacted.

This will have the impact of altering the climates of biomes.

The jet stream, which is one of the air patterns visible around the globe, could also change in speed and strength which would lead to changes in the type and intensity of local and global weather patterns.

Climate change impact on soil variability and erosion

Climate change impact on soil variability and erosion:

The increased temperatures would have the impact of drying out the soil which would lessen its effectiveness on holding soil in place, causing more soil erosion to happen through wind.

The increased water levels and storm intensity would have the impact of increased soil erosion through water.

Climate change impact of permafrost

As the globe is getting warmer the permafrost is melting, which is making the undecayed organic matter below the permafrost wet.

This leads to anaerobic decomposition of the organic matter, which is producing methane. Which is a greenhouse gases that has the impact of making the earth warmer, which further increase the impacts of the defrosting of permafrost, demonstrating that positive feedback loop.

Climate Change impact of Sea ice in the arctic.

Sea ice is a part of a polar bears natural habitat, as they use the sea ice to go out to where seals will create breathing holes so they can hunt them.

If the sea ice melts, it means that the polar bears no longer have a calorically efficient way of getting to those seals. And other hunting practices, like swimming, are not calorically efficient due to the fact that they require a lot of calories to execute, especially with the fact that seals are good swimmers.

This reduced the access they have to food and ultimately its a habit problem to.

Climate change impact on Coral reefs

Climate Change impact on Coral reefs:

As the sea levels rise it causes less UV ration to reach collar reefs, so they are prohibited from performing photosynthesis, because the increase water levels have the map of filtering out the UV light.

This influence the death of coral reefs as they temperature range is out of their range of tolerance (becoming hotter), and there is not sufficient sunlight to help them performe photosynthesis, so they ultimately die out. (coral bleaching; where the increase water temperatures can stress coral, causing them to expel their algae.)

Climate change impact of ocean currents:

Climate change impact of ocean currents:

Density changes in ocean current are impacted do to the melting of cool, freshwater from the glaciers and the warming of the ocean by increasing temperatures.

This impacts the direction of heat and cold through ocean currents.

Ocean warming

Is the global increase in ocean water temperatures. Though the amount of warming isn’t uniform across the globe—-some ocean areas have warmed more quickly than others.

This is caused by increased greenhouse gases in Earth’s atmosphere, such as carbon dioxide and methane.—-the IPCC estimates that our oceans have absorbed 93% of the excess heat from greenhouse gas emissions since the 1970’s.

In the graph that line would be the average (0.0^C & 0.0^F)

Ocean warming effects on habitat

Ocean warming affects marine species habitats in ways that includes:

1. Reduction of sea ice negatively impacts hunting/feeding patterns

2. Higher water temperature impact predator/prey interactions, as prey migrate to cooler areas.

3. Sea level rise alters coastlines, impacting species that use both land and water resources.

4. Rising Coastal seas may push some communities out of the photic zone

5. Warming oceans may impact primary productivity of phytoplankton, which are the basis of marine food webs.