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This article provides an overview of global climate change, explaining the difference between climate and weather, the human impact on radiative forcing, the role of solar activity, and the relationship between carbon dioxide and temperature. It also discusses the impacts of climate change on the environment and economy, the need for carbon emissions reduction, and the various approaches such as command and control, carbon taxes, tradable permits, and carbon offsets.
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Global Climate Change for Beginners Robert K. Kaufmann July 7, 2008 http://www.bu.edu/cees/people/faculty/kaufmann/index.html
Climate vs. Weather Weather: Conditions on any given day Temperature in Boston today is 91oF Climate: Average conditions on any given day over The average temperature in Richmond on July 7, is 83oF
Radiative Forcing of Sulfur Emissions Direct Effect
The Heat Balance of Planet Earth SOx Ground
Clouds The Heat Balance of Planet Earth SOx Ground
The Vostok Record From: Petit et al., Nature 399, 429 - 436 (1999
Changing Land-Use Deforestation Chopping down trees releases carbon dioxide Increasing termite habitat methane emissions Agriculture Rice paddies--human swamps emit methane Livestock--Methane ‘burps’
Human Sources of Carbon Dioxide 9000 8000 7000 Fossil Fuel 6000 5000 4000 3000 2000 1000 Deforestation 0 1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Humans are Not the Largest Source of Carbon Dioxide http://en.sevenload.com/videos/ha4PoKY/The-Great-Global-Warming-Swindle
How Much Doubt Really Exists? “Ifrising carbon dioxide is the cause of rising temperatures, why didn’t it cause temperatures to rise from 1940 to 1970? “Trust me, the satellite data have been reanalyzed dozens of times,…they show much less warming than expected by theory
Solar Activity is to Blame http://en.sevenload.com/videos/ha4PoKY/The-Great-Global-Warming-Swindle
Solar Activity 0.8 0.6 0.4 0.2 Solar Activity watts/m2 (Lean et al., 1995), 0 -0.2 -0.4 -0.6 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
No Relationship Between Carbon Dioxide and Temperature http://en.sevenload.com/videos/ha4PoKY/The-Great-Global-Warming-Swindle
Climate Models: How, Where, and By How Much Will Climate Change?
Causes For Temperature Change Doubling of radiative forcing……………1.2oC Increased water vapor……….. ……….1.6oC Increase in clouds………………………..0.8oC Changes in surface albedo……………….0.4oC Other changes……………………………0.2oC Total change in temperature…………….4.2oC
Climate change impacts on the environment & economy Change in sea level Impact on agriculture Impact on biomes Water Supply
Changes in Sea Level Melting of glaciers and polar ice Thermal expansion of water
Impacts on Agriculture Benefits Costs Longer growing season Mid Continent Drying CO2 Fertilization Warmer nights Water use efficiency
Climate Change & Extinction Climate change scenario Migration rateMinimum Middle High Universal dispersal 9-13 15-20 21-32 No dispersal 22-31 26-37 38-52 Thomas et al, 2004 Nature 427:145-148.
By How Much Should Carbon Emissions Be Reduced? What does society “give up” What does society gain?
Command & Control Benefits Politicians can measure their effects Invisible taxes Reductions known Costs May not be least cost No incentive for further reductions No incentive for technical development Cumbersome
Carbon Taxes Tax reflects the marginal damage of carbon emissions Higher cost reduces emissions Replace energy use with capital or labor Replace high carbon fuels with low carbon fuels Tax rate based on carbon content of fuel ($100 ton) Gasoline ($1.00 per gallon) $2.80 per gallon Natural gas ($6.00 per tcf) $12.91 per tcf Coal ($100 per ton) $55 per ton Electricity ($0.11 per Kwh) $0.11 per Kwh
Carbon Taxes Advantages Least cost reduction Cost is well known Constant incentive to reduce emissions Constant incentive to improve technology Easy to implement Disadvantages Reductions are not well known Taxes Kiss of death
Tradable Permits Advantages Reductions well known Least cost reduction Constant incentive to reduce emissions Constant incentive to improve technology Proven to work well (US sulfur market) Disadvantages Cost of permit unknown Strong institutions Good governance
Carbon Offsets Commercial providers Boston-Nashville round trip 2,043 miles Emissions 1,009 pounds carbon $9.95 in Offsets Offsets reduce emissions elsewhere