Climate Change

I. Greenhouse gases and potencies

A. Gases in the atmosphere that absorb infrared radiation and radiate it back to earth are called greenhouse gases.

B. Major greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone.

I. Greenhouse gases and potencies

C. Carbon dioxide – NOT the most potent greenhouse gas, but by far the most abundant.

D. Natural sources of carbon dioxide in the atmosphere include volcanic eruptions and animal respiration.

E. Anthropogenic sources include burning fossil fuels (coal, oil, and natural gas) and deforestation.

F. Not all fossil fuels are created equal – burning natural gas released only 56% of the CO2 that coal does. Additionally, when coal is burned particulate matter released called “black soot” covers things and reduces albedo, heating things up even more.

G. Atmospheric carbon dioxide levels have risen exponentially since the start of the Industrial Revolution.

H. Atmospheric CO2 levels were 280 parts per million (ppm) 275 years ago, and were 390 ppm in 2010. This is the highest concentration of atmospheric CO2 in over 650,000 years.

I. Levels are rising at approximately 2 ppm a year (or 3.3% a year).

J. At this rate, by 2050 the level will be 560 ppm.K. 450 ppm is considered a crucial and

irreversible tipping point, and 350 ppm is considered the level for climatic stability.

L. Who emits the most CO2?

1. In pure volume; China, US, EU, Indonesia, Russia, Japan, (if Texas was a country we would be here) and India

2. Cumulative CO2 emissions since the start of the industrial revolution: US (25%), EU (22%), China (5%)

3. Per Capita CO2 emissions: US – 15 tons, UK - 9.2 tons, World- 4 tons, China 3.2 tons, India - 1.0 tons

M. Water vapor – it is the most abundant greenhouse gas in terms of composition of the atmosphere, and the greatest natural contributor to the greenhouse effect. There is little anthropogenic effect of adding water vapor to the atmosphere.

N. Methane (CH4) is another potent green house gas which has seen anthropogenic increases of over 60% since the industrial revolution. Methane is 21 times more potent than carbon dioxide.

O. Naturally, methane is released from anaerobic decomposition (decomposition without oxygen). The largest natural sources of methane is wetlands, the second largest natural source is termite gut decomposition.

P. Largest anthropogenic releases of methane include:

1. Livestock (cow and sheep burps) 24%, 2. Landfills (anaerobic decomposition of trash) 23%

3. Leaking natural gas/petroleum infrastructure (drilling, etc). 21% 4. Coal production, large manure lagoons, and rice

production (submerged/flooded fields) also contribute to anthropogenic methane release.

II. Greenhouse gases and potencies

Q. Nitrous oxide (N2O) – Traps 300 times as much heat as carbon dioxide, but is found at very low concentrations in the atmosphere.

R. Naturally nitrous oxide is produced when bacteria break down nitrogen compounds in wet soils, and at the bottom of wetlands and oceans.

S. Anthropogenically, nitrous oxide is produced is produced when agricultural fields are over-fertilized with nitrogen containing fertilizers (70%), and from combustion of fossil fuels in cars (18%).

T. Ozone and CFCs also contribute.

Global warming potential = how much one molecule of a compound can contribute to global warming over 100 years compared to CO2

Greenhouse Gas Concentration in 2010 Global Warming Potential

Water vapor Variable with temperature Less than 1

Carbon dioxide 390 ppm 1

Methane 1.8 ppm 25

Nitrous oxide 0.3 ppm 300

Chlorofluorocarbons 0.9 ppm 1,600 to 13,000

II. Greenhouse gases and potencies

L. Balloon Mini –Demo:1.Which gas is better at trapping balloon

“heat”? ______________________2.This means the gas is more _____________3.Which gas is more concentrated in the

atmosphere? ___________________4.Which gas ends up having a greater ability to

trap the most heat? ____________________

III. Historical Climate Analysis and Current Research

A. Since we can’t actually go back in time to measure atmospheric carbon dioxide concentrations, we have to use proxy indicators.

B. Proxy indicators = types of indirect evidence that serve as substitutes for direct measurements

C. Trapped bubbles in ice cores show atmospheric composition, greenhouse gas concentration, temperature trends, snowfall, solar activity, and frequency of fires.

D. Cores in sediment beds preserve pollen grains and other plant remnants

E. Tree rings indicate age, wetness of the season, droughts and seasonal growth

F. Researchers also gather data on past ocean conditions from coral reefs

G. Growth rates and isotopic compositions of cave speleothems have been used in Texas to look at precipitation rates.

H. In 1988, UN and the World Meteorological Organization established the Intergovernmental Panel on Climate Change (IPCC) to document past climate changes and project future changes. The IPCC working group includes more than 2,500 climate experts from more than 130 countries.

I. The 2007 report was based on more than 29,000 scientific sets of data, much of it collected since 2002. Some of the major conclusions include:

1. Between 1906 and 2005 the average global surface temp has risen by about 1.3 F, with the majority of the increase occurring since 1980.

2. Annual greenhouse gas emissions from human activities rose 70% between 1970 and 2005.

3. Over the past 50 years, arctic temps have risen twice as fast as average temps in the rest of the world.

4. During the last century, the world’s average sea level rose by 10-20 centimeters.

IV. Effects of Climate Change A. Katharine Hayhoe, a climatologist in Texas “As our

atmosphere becomes warmer, it can hold more water vapor. Atmospheric circulation patterns shift, bringing more rain to some places and less to others. For example, when a storm comes, in many cases there is more water available in the atmosphere and rainfall is heavier. When a drought comes, often temperatures are already higher than they would have been 50 years ago, and so the effects of the drought are magnified by higher evaporation rates.”

B. Precipitation pattern changes – some areas will receive more precipitation, and some less

1.Droughts have become more frequent and severe, with effects on agriculture and increased risks of fires.

2.Heavy rains have contributed to major flooding

C. Melting Ice and Rising Seas – over two-thirds of sea level rise thus far is attributed to thermal expansion of the ocean.

1.Mountain glaciers are disappearing at an accelerating rate – by 2030 no more glaciers left in Glacier National Park.

2.As large Greenland and Antarctic Ice sheets melt, darker less reflective surfaces are exposed, causing more rapid melting.

D. Agriculture and Forestry – Growing seasons and precipitation patterns changed

1.Crops more susceptible to failure during drought or flood

2.Crop production projected to decrease, often in areas of subsistence farming.

3.Increased insect and disease outbreaks in forests, increased chance of forest fires.

E. Ecosystem Health: Organisms are adapted to their environments, so they are affected when those environments change

1.Global warming modifies temperature-dependant phenomenon like migration and breeding

2.Spatial shifts in the range of organisms – animals move up in elevation or latitude

3.20-30% of all species threatened with extinction

F. Human Health – Expansion of tropical diseases like Malaria or West Nile, warmer winters prevent die offs or allow more robust populations of infectious organisms

G. Special Polar Issues 1. The arctic/Antarctic has already warmed by

1 – 4 C.2. Losing ice rapidly – Greenland and Antarctica

between 2000-2008 each lost 3,000 TRILLION pounds of ice cover! Ice melting is a positive feedback loop – as ice melts, albedo (reflectivity) of area greatly decreased, which causes greater heat absorption and yet more rapid ice melt!

Permafrost – the big elephant in the room!

3. Permafrost is permanently frozen ground that exists at high altitudes and latitudes. 20% of the Earth is permafrost.

a) Lots of organic matter frozen in tundra, when it melts there is lots of decomposition in a wet, anaerobic environment. Gives off TONS of methane.

V. How bad Could it be?

A. 450 ppm (3.6° F – now unavoidable effects)• Prolonged droughts intensify• Deserts spread• Major heat waves common• Conflict over water supplies increase• Coral reefs affected by bleaching• Many glaciers melt faster and threaten water

supplies for up to 100 million people

A. 450 ppm (3.6 °F – now unavoidable effects)

• Sea levels rise enough to flood low-lying costal areas like Bangladesh

• More people exposed to malaria• High risk of extinction of polar species

B. 550 ppm – 3 °C Temperature Rise

Forest fires get much worse Prolonged droughts get much worse Major heat waves and deaths from heat increase 1.4 billion people suffer water shortages Water wars, environmental refugees, and

terrorism increase Malaria and several other tropical diseases

spread further and faster

550 ppm – 3° C Temperature Rise

• Crop yields fall sharply in many areas, especially Africa

• Amazon rainforest may begin collapsing• Up to half of Arctic tundra melts• Sea levels continue to rise• 20-30% of plant and animal species face

premature extinction

C. 650 ppm CO2, with 4° C warming

• Forest fires and droughts increase sharply• Water shortages affect almost all people• Crop yields fall sharply in all regions and cease

in some regions• Water wars, environmental refugees,

terrorism, and economic collapse increase sharply

650 ppm CO2, with 4° C warming

• Ecosystems such as coral reefs, tropical forests, costal wetlands, alpine and Arctic tundra begin collapsing

• Sea levels rise faster and flood many low-lying cities and agricultural areas

• At least half of plant and animal species face premature extinction.

VI. What to do?

A. Mitigation = pursue actions that reduce greenhouse gas emissions, in order to lessen severity of future climate change– Renewable energy sources, transportation

strategies, preventing deforestation

B. Adaptation = accept climate change is happening and pursue strategies to minimize its impacts

VI. What to do? C. Electricity Generation - Largest source of U.S.

CO2 emissions

D. Two ways to reduce fossil fuel use: conservation and/or alternative energy1. Replacing worn-down appliances with newer

models, lifestyle choices, increased insulation and thermal efficiency of homes

2. Chose “Green Choice” energy generation options from utility where available.

V. What to do? E. Transportation is 2nd largest U.S. greenhouse

gas emission categoryF. The typical automobile is highly inefficient,

possibilities for increasing efficiency include:1. Technology: make vehicles more fuel-efficient,

hybrid cars2. Drive less and use public transportation3. Live nearer your workplace, so you can bike or

walk

VI. What to do?

G. Deforestation huge source of emissions as well 1. Prevent where possible 2. Reforestation of deforested areas

H. The Kyoto Protocol seeks to limit emissions

1. The Kyoto Protocol mandates that, between 2008-2012, signatory nations must reduce emissions of six greenhouse gases to levels 5.2 % below those of 1990 – This treaty took effect in 2005, after Russia became the

127th nation to ratify it 2. The United States will not ratify the Kyoto Protocol

because it requires industrialized nations to reduce emissions, but it does not require the same of rapidly industrializing nations such as China and India

3. Businesses in industrialized nations feel they have more to lose economically from restrictions

I. Advancing climate change policy1. Local Action - –State and local governments across the

U.S. are responding and advancing policies to limit greenhouse emissions –Mayors from all 50 states signed the

U.S. Mayors Climate Protection Agreement, where the mayors commit their cities to pursue policies to “meet or beat” Kyoto Protocol guidelines

2. California’s legislature passed the Global Warming Solutions Act, which aims to cut the state’s greenhouse gas emissions 25% by the year 2020

3. 10 northeastern states launched the Regional Greenhouse Gas Initiative (RGGI) in 2007, which set up a cap-and-trade program for carbon emissions from power plants

J. Carbon offsets/Cap and Trade1. Emissions trading programs allow

participants who cannot or will not reduce their emissions to use carbon offsets instead

2. Carbon offset = a voluntary payment to another entity intended to enable that entity to reduce the greenhouse emissions that one is unable or unwilling to reduce oneself –Becoming popular among utilities,

businesses, universities, governments, and individuals trying to achieve carbon-neutrality, where no net carbon is emitted

K. How Does Cap and Trade Work?

Traditional government regulation of pollutants follows a command and control model – Government sets maximum amount of pollution (which can include CO2) that can be emitted for any business in an industry – requires laws, regulation, and enforcement.

L. Cap and Trade – The CAP is a limit on TOTAL amount of pollution to be emitted by a region. The TRADE is that companies buy and sell permits for a given amount of pollution. A market incentive to reduce pollution, as long as there is a cost associated with polluting vs. buying the permits.

M. Cap and trade has been used to regulate and reduce sulfur dioxide emissions from power plants as part of the Clean Air Act.

N. Has worked successfully – 64% reduction in sulfur emissions from 1990 – 2009, greatly helping reduce issues with acid rain.

2005 – EU started carbon cap and trade system

O. Some issues – exemptions for certain industries or older power plants, and offsets may allow companies to keep releasing the same amount of CO2, needs to be implemented in a large region scale to not unfairly penalize companies operating only in certain regions.