C.  Climate Change

• Changes in the global climate, including temperature, precipitation, storm frequency and intensity, and changes in carbon and water cycles

• Results from increased concentrations of greenhouse gases in the atmosphere

• Greenhouse gases - gases such as carbon dioxide and methane whose atmospheric concentrations influence global climate by trapping solar radiation

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• Global warming - the increase in average global temperature as a result of emissions from human activities

• Greenhouse effect - certain gases (carbon dioxide, methane, nitrous oxide, ozone plus clouds and water vapor) in the atmosphere trap solar radiation

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Global Annual Temperature Anomalies (°C), 1850–2015

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1.  Framework for economic analysis

a.  Greenhouse gas emissions are a negative externality

b.  The atmosphere is a common property resource

c.  Dealing with climate change is a public good

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2.  Causes

• Greenhouse gases are cumulative or stock pollutants - don't dissipate or degrade significantly over time, can accumulate in the environment

• Biggest contributor has been the use of fossil fuels

• Burning of coal generates the most carbon dioxide (42%), followed by oil (33%) and natural gas (19%)

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• Increasing emissions by developing countries

Percentage of Global CO₂ Emissions by Country/Region

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3.  Impact

a.  Ecosystem impacts

• Glaciers retreating

• Rising sea levels

• Warmer ocean waters

• Ocean acidification - ocean water becoming more acidic

• Disruption of weather patterns - more extreme events (hurricanes, drought)

• Positive feedback effect - warming releases more carbon dioxide from frozen arctic tundra

• Increased wildfires

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b.  Economic impacts

• Loss of land area because of sea-level rise

• Loss of species and forest area

• Disruption of water supplies to cities and agriculture

• Increased air conditioning costs

• Health damage and deaths from heat waves and spread of tropical diseases

• Loss of agricultural output due to drought

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c.  Positive impacts

• Increased agricultural production in cold climates

• Lower heating costs

• Fewer deaths due to exposure to cold

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4.  Climate change and inequality

• Impact of climate change would fall more heavily on the poor

• Reduced food production, water shortages, coastal flooding, damage to forests and agriculture due to drier conditions

• Environmental justice - fair treatment of people with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies

• Climate justice - equitable sharing of the burdens of climate change and the costs of policy responses

- Frames climate change as an ethical and political issue in addition to being an environmental or physical issue

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5.  Climate stabilization

• Goal should be to maintain stability of the physical and ecological systems instead optimization of benefits and costs