NSCI 102 Ch 19

Why the clearing of forests and grasslands and burning of fossil fuels have contributed to rapid atmospheric warming

- Forests and grasslands remove excess CO2 from the atmosphere, so when we clear them, we are allowing more CO2 to be left in the atmosphere. - Burning fossil fuels has added CO2 to the atmosphere faster than the carbon cycle can remove it.

Climate change is a difficult environmental problem because...

- It's global. Dealing with it will require prolonged international cooperation - it can be slowed but not fully stopped, the CO2 will be in the atmosphere for 100 years - It is a long-term political issue, elected officials focus on short-term probs - Proposed solutions, like sharply reducing use of fossil fuels, are controversial

Five sources of information used by scientists to study climate changes of the past

- ancient ice - buried pollen grains - tree rings - historical/on-going changes in ocean chemistry and water temps (look at layers in coral reefs) - radioisotopes in rocks/fossils, radioisotopes and plankton in ocean sediments, and atmospheric temps

Cap-and-trade policy advantages

- clear legal limit on emissions - rewards cuts in emissions - record of success - low expense for consumers

What species will be hit the hardest by harmful effects of climate change?

- cold-climate plant/animal species, including polar bears in the Arctic and penguins in Antarctica - species that live at higher elevations - species with limited tolerance for temp change, like corals - species with limited ranges ... These are all due to loss of habitat.

Prevention measures

- cut fossil fuel use - shift from coal to natural gas - improve energy efficiency - reduce deforestation - put a price on greenhouse gas emissions

What changes have been observes in the earth's glaciers? Sea levels? Permafrost? Ocean temps?

- glaciers are melting - sea levels are rising and eroding/flooding coastlines - permafrost is thawing - ocean temps are rising because the oceans have been removing 90% of the excess heat the humans have caused

3 Major problems with geoengineering strategies

- if they succeed, they could be used to justify continuing to depend on fossil fuels for most of our energy - if we rely on them and continue emitting greenhouse gases, and they fail, then atmospheric temps will likely soar at a rapid rate and ensure climate disruption - one country, one company, or one wealthy individual could undertake a project that could be harmful to whole regions or to the entire planet

Geoengineering strategies

- placing giant mirrors in orbit above earth to reflect sunlight and slow the warming of the troposphere - using balloons, large jet planes, or giant cannons to inject large amounts of sulfate particles into the stratosphere to reflect some of the incoming sunlight into space - deploy global fleet of computer-controlled ocean-going ships to such up ocean water and spray saltwater high into the sky to make existing clouds thicker and whites and reflect more incoming sunlight back to space

Cap-and-trade policy disadvantages

- revenues not predictable - vulnerable to cheating - rich polluters can keep polluting - puts variable price on carbon

Cleanup measures

- sequester CO2 by planting trees and preserving forests/wetlands - sequester CO2 in the deep ocean (with no leaks) - remove CO2 from smokestack and vehicle emissions

Carbon and energy tax advantages

- simple to administer - clear price on carbon - covers all emitters - predictable revenues

Carbon and energy tax disadvantages

- tax laws can get complex - vulnerable to loopholes - doesn't guarantee lower emissions - politically unpopular

Problems with using current carbon capture and storage (CCS) technologies

- they can remove and store no more than 80% of the CO2 from smokestack emissions at great cost - they do not deal with the massive emissions of CO2 from motor vehicle exhausts, food production, and the deliberate burning of forests to provide land for growing food - they require a lot of energy, which could lead to greater use of fossil fuels and higher emissions of CO2 and other air pollutants

Greenhouse effect

A natural process that plays a minor role in determining the earth's average atmospheric temp and climate. Occurs when some of the solar energy absorbed by the earth radiates into the atmosphere as infrared radiation. As radiation interacts w/ molecules of greenhouse gases in the air, it increases their kinetic energy and warms the lower atmosphere/earth's surface.

Outdoor air pollution (aerosols and pollutants)

Aerosols from human activities can reduce or enhance the greenhouse effect and cloud formation, depending on size and reflectivity. Light-colored sulfate aerosols from burning fossil fuels reflect sunlight and cool the lower atmosphere. Black carbon aerosols (soot) from coal-burning, diesel exhaust, and burning forests warms the lower atmosphere. These particles will most likely not affect earth's atmospheric temp because they fall back to the earth/are washed out of the lower atmosphere in weeks. Also, they are being reduced through air pollution regulations.

How does the amount of carbon dioxide in the atmosphere measured in 2019 compare with levels during the past 400,000 years?

After oscillating between 180 and 280 ppm for 400,000 years, atmospheric CO2 levels reached an average of 415 ppm in 2019—higher than at any time in the last 800,000 years according to NOAA scientists.

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After several decades of peer-reviewed research, discussion, and debate, there is no significant debate/disagreement among most of the world's climate scientists. Because scientists are highly skeptical and question the results of all research, this level of agreement among scientists is rare.

Effects of climate change in Alaska

Alaska is warming at twice the average rate of the rest of the United States. In 2018, all but 5 glaciers were shrinking. Coastal sea ice is disappearing two weeks earlier in the summer and refreezing two weeks later in the fall. This has shortened the hunting season by a month for walruses/polar bears. 31 coastal villages are planning on relocating to higher ground. Permafrost is freezing. Also, there has been an explosion of beetle populations which are wiping out white spruce forests.

How have species migration patterns changes in recent decades?

As temps have risen, terrestrial/marine/freshwater species have migrates toward the poles, and on land they have migrated to cooler, high elevations.

Melting ice/snow

As the atmosphere warms, ice and snow will melt, resulting in darker/less reflective land/ocean water. This will further increase atmospheric warming above the poles, melt more ice/snow, and increase the temp of polar oceans. (Creates a positive feedback loop).

How have atmospheric carbon dioxide levels changes since 1960?

Atmospheric levels of CO2, CH4, etc that warm the troposphere have been rising sharply

Why is there uncertainty in the models scientists use?

Because of uncertainty about projections on how much CO2 / other greenhouse gases we are likely to add to the atmosphere during the next decade and so on.

Climate

determined by average weather conditions over periods of at least 30 years

Weather

hour-to-hour, day-to-day, short term

Adaption

recognizes that some climate change is unavoidable because we have waited too long to act and that we need to adapt to some of the harmful effects

What actions will be required to reduce carbon dioxide emissions enough to avoid exceeding a global average temp increase of 1.5 C?

reducing the use of fossil fuels, greatly increasing energy efficiency, and shifting to much greater dependence on cleaner and low-carbon energy resources such as solar power, wind power, and geothermal energy.

Carbon footprint

the amount of CO2 generated by an individual, an organization, a country, or any other entity over a given period

Per capita carbon footprint

the average footprint per person in a population

Climate change tipping points

thresholds beyond which damage to natural processes could last for hundreds to thousands of years

Mitigation

to slow down climate change to reduce or avoid its most harmful effects

Cap-and-trade approach

when regulators place a cap on total human-generated emissions of a gas or releases of a pollutant in a country or region

Climate change occurs...

when there are changes in global weather patterns based primarily on changes in the earth's atmospheric temperature averages over a period of at least 30 years.

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Burning fossil fuels, deforestation, and agriculture have led to a significant increase in the concentrations of greenhouse gases in the atmosphere

How much has the average global surface temperature risen above preindustrial levels?

By 2018, the earth's average global surface temp had risen by 1.0C (1.8F) above preindustrial levels, with much of the increase taking place since 1975.

How do the carbon dioxide emissions of the U.S. compare to other countries?

China has the largest national carbon footprint, then the U.S., Europe, India, Russia, then Japan. So the U.S. is second among these nations.

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China is rapidly becoming the world leader in developing and selling low-carbon solar cells, solar water heaters, wind turbines, advanced batteries, and plus in/all-electric cars. They have agreed to cap their CO2 emissions and fossil fuel use (especially coal, which provides 80% of its electricity), but only after 2030.

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Climate change/disruption makes more sense than global warming because not everywhere gets warmer. Some places get warmer, while others get colder because of interactions in the planet's complex climate system.

Extreme weather

Extreme weather can not be linked to climate change, but with more heat in the atmosphere, scientists think climate change will increase the chances and intensity of extreme weather events. Because a warming atmosphere can hold more moisture, places like the eastern half of the U.S. could experience increased flooding from heavy/prolonged snow and rainfall. Atmospheric warming can cause more extreme heat, but also colder winters. Soon, heat may become unbearable to withstand.

Kyoto Protocol

First phase of a treaty made to slow atmospheric warming ans projected climate change. The 37 participating more-developed countries agreed to cut their emissions of CO2, CH4, and N2O to certain levels by 2012. However, 16 of the nations failed to do so.

Threats to national security

Flooding could endanger 128 military bases. There would be increased food and water shortages, poverty, environmental degradation, unemployment, social unrest, mass migration of environmental refugees, political instability, and the weakening of fragile governments.

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For the last 10,000 years, the earth has experienced an interglacial period with a generally stable global average surface temperature. It has allowed the human population to grow and develop agriculture, and eventually cities. However, since 1975, the earth's average atmospheric temps have been rising.

How can subsidy payments be used to help slow climate change?

Governments can slow climate change by greatly increasing subsidy payments to businesses and individuals working on energy-efficiency technologies, low-carbon renewable energy courses, and more sustainable food production methods. They could also phase out subsidies and tax breaks that encourage the use of fossil fuels, unsustainable agriculture, and the clearing of forests.

Technology transfer

Governments of more-developed countries could help to fund the transfer of the latest green technologies to less-developed countries so that they could bypass older, energy-wasting and polluting technologies.

Why will methane levels increase even faster if global temps continue to rise?

Some areas of permafrost in the arctic tundra and the Arctic Ocean seabed are expected to thaw and release a large volume of CH4 and CO2 to the atmosphere. Also, methane will be released through cracks in floating arctic ice.

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Some schools, like State Uni of New York and University of Vermont, are purchasing organic food from local sources, diverting waste from landfills and incinerators, and having sustainability officers/sustainability committees.

No-regrets strategy

Strategies that do tons more good than harm. They are worth the little bit of harm if they help implement needed changes. They will lead to important environmental, health, and economic benefits, including energy independence, millions of new jobs, cleaner air, and stronger national and economic security.

Geoengineering

any use of technology to try to manipulate certain natural conditions in order to counter our enhancement of the greenhouse effect

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colder or warmer winter, year, or decade is a change in weather and not necessarily a sign of climate change, because it involves less than 30 years of data

Carbon dioxide (CO2) atmospheric warming potential

1

Nine natural factors that have altered the earth's climate in the ancient past

1. Massive volcanic eruptions and impacts by meteors/asteroids that cool down the earth. They cool down the earth 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 circular 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. 6. Global air circulation patterns. 7. Changes in sizes of areas of ice that reflect incoming solar energy and cool the atmosphere. 8. Changes in atmospheric concentrations of greenhouse gases. 9. Occasional changes in ocean currents.

Carbon dioxide (CO2) atmospheric lifetime

100 yrs (varies 50-200 yrs)

Nitrous oxide (N2O) atmospheric lifetime

114 yrs

Methane (CH4) atmospheric lifetime

12 yrs

Nitrous oxide (N2O) atmospheric warming potential

300

Methane (CH4) atmospheric warming potential

34

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377 U.S. universities and colleges have reduced their emissions by 8% per square foot since 2007. By 2016, the University of Minnesota, Vermont's Green Mountain College and Middlebury College, and Maine's Colby college and College of the Atlantic had achieved net zero carbon footprints.

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Costa Rica aims to be the first country to become carbon neutral by cutting its net carbon emissions to zero by 2030. The country generates 78% of its electricity with hydroelectric power and another 18% from wind and geothermal energy.

Food production

Crop production is projected to increase slightly with moderate warming in areas such as midwestern Canada, Russia, and Ukraine. However, the projected rise in crop productivity could be limited because the soils in the northern regions lack sufficient plant nutrients. As locations of severe droughts and patterns of rainfall change, farmers will have to change when and where they grow food. Pork, beef, poultry, and milk production are projected to decline. Warmer winters will affect the production of fruits like apples and cranberries. There will be more crop diseases, insect pests, and weeds. As temps rise, food production will decrease.

How are people lowering their CO2 emissions?

Driving fuel-efficient vehicles, walking, biking, washing clothes in warm or cold and hang drying, eat less/no meat, energy-efficient windows, plant trees, but from environmentally friendly businesses.

Severe drought

Drought occurs when evaporation from high temps exceeds precipitation for a prolonged period. Not all drought is caused by human caused warming, but is usually caused by natural processes. However, scientists think higher temps due to atmospheric warming is intensifying the water cycle and adding more water vapor to the atmosphere. This would increase the warming effect and lead to more evaporation followed by greater warming. (Positive feedback loop). Long periods of drought could hinder tree and plant growth, meaning less CO2 would be taken from the atmosphere.

Threats to economies

Economists estimate that the cost of climate change, if current trends continue, would be 5-20% per year of the world's economic activity as measured by gross domestic output. Intense drought, flooding, and extreme weather events will contribute to lower economic productivity, disruption of supply chains, higher costs for food and other commodities, and increases financial risk for companies and investors.

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Greenland's ice has been melting, and so the oceans are getting warmer, which makes the atmosphere get warmer. It creates a cycle of climate change/disruption. Greenland's ice loss has been responsible for nearly ⅙ of the global sea-level rise over the past 20 years. Their ice sheets are melting at the fastest rate in 350 years. This is an early warning that human activities are very likely to disrupt the earth's climate in ways that would threaten life and disrupt our economies.

Thawing permafront

If permafrost continues to thaw, microorganisms will decompose a large amount of the organix material found below the permafrost. This would release a huge amount of CO2 and CH4 into the atmosphere. Also, there is methane held within the permafrost that could make warming worse.

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Life on earth depends on on the greenhouse effect because it keeps the planet at an average temp. Without the natural greenhouse effect, the earth would be frozen and uninhabitable.

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Livestock production, rice production, natural gas production, landfills, and the flooding of land behind large dams have increased the concentration of methane in the atmosphere

How does the concentration of carbon dioxide in the atmosphere relate to average atmospheric temperature?

Measurements of CO2 in air bubbles at various depths in ancient glacial ice indicate that changes in the levels of this gas in the lower atmosphere have played a role in the global average temperature near the earth's surface during the past 400,000 years.

Threats to human health

More frequent/prolonged heat waves will increase deaths and illnesses, especially among older people, poor health people, and people w/out air conditioning. More CO2 means more insects, which can transmit diseases, and make toxic molds and fungi grow.

How does the current rate of atmospheric warming compare with rates of climate change in the past? And why is it a concern?

Most historic changes in the temp of the lower atmosphere took place over thousands of years. The current problem is urgent because we are facing a rapid projected increase in the average temp of the lower atmosphere during this century. This will very likely change our mild climate weve had for the past 10,000 yrs.

Adaption strategies

Organizations are carrying out projects such as expanding mangrove forests as buffers against rising storm surges and flooding, building shelters, and planting trees on slopes to prevent landslides. The government in the Netherlands has been formulating a 200-year plan for dealing with climate change. Coastal U.S. communities are requiring new house/construction to be built higher off the ground and further back from the current shoreline. Cities are redesigning transportation, housing, waste management, and water/food systems.

"Living with the water"

Plan in the Netherlands, they will let flooding occur ans steer it to certain sparsely populated areas and to water plazas created in urban areas for temporary floodwater storage. Affected homeowners will be compensated as necessary or moved at government expense.

Ocean acidification

Rising levels of CO2 have increased ocean acidity. CO2 absorbed by the ocean reacts with water and produces carbonic acid, which is found in carbonated drinks. The higher the acidity rises, coral, snails, oysters, etc are threatened. There shells/bodies are made of calcium carbonate, so acidity would hinder their ability to build/repair such structures. Also, increases acidity can decrease populations of plankton, which remove CO2 from the atmosphere.

How do scientists use mathematical models to project future changes in atmospheric temps?

Scientists run there models on supercomputers and compare the results to known past atmospheric temps. They then use the data/models to project future changes in the earth's average atmospheric temperatures.

Variation in solar output

Since 1975, the sun's energy output has dropped slightly. The troposphere has warmed, and the stratosphere has cooled. This is the opposite of what it would be if the sun were getting hotter. Instead of the sun heating the atmosphere from the top down, data shows that atmosphere is heating from the bottom up.

How do temp changes in the arctic compare to changes around the rest of the planet?

Since 2014, the Arctic has been warmer than at any time since temp records began in 1900

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Some U.S. state and local governments are moving ahead in dealing with climate change. By 2018, 20 states had set targets for reducing their greenhouse gas emissions. California has set a goal of reducing its greenhouse gas emissions 40% by 2030 compared to 1990 levels.

Why is the thawing of permafrost a positive feedback loop that could lead to a tipping point?

The 5-10% of methane in Arctic permafrost would accelerate atmospheric warming, thaw more permafrost, and lead to increase atmospheric warming/climate change. This creates a positive feedback loop leading to a tipping point.

When have the hottest years on record occurred?

The 6 warmest years on record since 1861 have occurred since 2010, and 17 of the 18 warmest have occurs since 2000.

How do the per capita carbon dioxide emissions of the U.S. compare to other countries?

The U.S. has one of the world's largest per capita carbon footprints. We have emitted more CO2 than any other country.

3 Climate Scientist Conclusions

The earth's climate is changing rapidly, and the change will accelerate unless we act now to slow it. Human activities that emit CO2, like burning fossil fuels and clearing forests/grasslands that help remove excess CO2, have been dominant causes of atmospheric warming and climate change since 1965. Climate change cannot be stopped, but sustained action to slow climate change over the next 3-4 decades is possible/affordable. It would bring significant human health, economic, and environmental benefits if we implement such action now.

Ability of the oceans to absorb heat and carbon dioxide

The ocean removes around 25% of the CO2 pumped into the lower atmosphere by human activities. Oceans also absorb heat from the lower atmosphere. Because of this, the average temp of the ocean has risen since 1970. The ability of the oceans to absorb CO2 decreases as water temps rise, so as the ocean warms, the CO2 will be let back out, which makes atmospheric warming/cliamte change worse.

Rising sea levels

The oceans absorb more than 90% of the extra heat in the atmosphere, but as they store more heat, they expand since warmer water takes up more space than cold. This could cause degradation of castal wetlands, coral reefs, etc. It will cause flooding in low-lying countries, erosion of low lying islands, submersion of islands, and contamination of coastal aquifers. People will have to migrate more inward on land.

How have nitrous oxide levels changed over the past 275 years?

They have risen 20% during the last 275 years because of the increased use of nitrogen fertilizers.

Forest health

Up to 85% of the Amazon rain forest could be lost and converted to tropical savanna if the global atmospheric temp rises by the highest projected amount. A warmer climate is also increasing populations of insects and fungi that damage trees, especially in areas where winters are no longer cold enough to control their populations. Rocky Mountain forests could die due to extreme heat, drought, wildfires, and beetle infestations.

Cloud cover

Warm temps increase evaporation of surface water, which raises the humidity of the atmosphere, resulting in more clouds that can cool or warm the atmosphere. An increase in thick, continuous cumulus clouds at low altitudes would be cooling because they reflect more sunlight back to space. An increase in thin, wispy cirrus clouds as high altitudes would be warming because they allow more sunlight ro reach earth.

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We are close to the estimated tipping points. For example, in 2019, the CO2 level was 415 ppm, and 450 ppm is the tipping point.

The Paris Agreement

Went into effect in November 2016, with more than 55 countries (not the U.S.) ratifying it. They accepted the goal to keep the increase in global average temps below 2C, pledged to reduce greenhouse gas emissions by a set amount, and they will meet every 5 years to evaluate progress/raise goals. The U.S. withdrew from the Paris Agreement in late 2020.