The Greenhouse Effect
The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases (Intergovernmental Panel on Climate change, 2010). There is not a debate about the importance of the greenhouse effect. Greater concern arises because human activities are raising the atmospheric concentrations of the greenhouse gases (most significant greenhouse gases are carbon dioxide, methane, and chlorofluorocarbons (CFCs) respectively). The Environmental Protection Agency (EPA) finds that atmospheric concentrations of these greenhouse gasses have risen by over fifty percent of the preindustrial level of carbon dioxide (measured using standard metric, ‘CO
2
equivalent’).
The actual change in future climate is uncertain, as different estimates vary widely. The
Intergovernmental Panel on Climate Change (IPCC) project that ‘business as usual’ would
produce a 3 to 6 degree C warming in 2100 relative to 1900 (Nordhaus, 2005). This model does not w
ork very well because it completely ignores price, which would not allow ‘business as usual’ to persist until 2100. An economic model known as the DICE model (Dynamic Integrated
Model of Climate and the Economy) looks at price. Economic models project rising relative energy prices and slowing economic growth in the coming decades; as a result, they tend to show lower emissions and temperature trends than the extrapolative approaches often used in the scientific community and demonstrated by the IPCC projections above (Nordhaus, 2005). The DICE models lesser projected increase of about 2 to 4.5 degrees C is still problematic and has an impact on economic systems
The Greenhouse EffectThe greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases (Intergovernmental Panel on Climate change, 2010). There is not a debate about the importance of the greenhouse effect. Greater concern arises because human activities are raising the atmospheric concentrations of the greenhouse gases (most significant greenhouse gases are carbon dioxide, methane, and chlorofluorocarbons (CFCs) respectively). The Environmental Protection Agency (EPA) finds that atmospheric concentrations of these greenhouse gasses have risen by over fifty percent of the preindustrial level of carbon dioxide (measured using standard metric, ‘CO2equivalent’). The actual change in future climate is uncertain, as different estimates vary widely. TheIntergovernmental Panel on Climate Change (IPCC) project that ‘business as usual’ would produce a 3 to 6 degree C warming in 2100 relative to 1900 (Nordhaus, 2005). This model does not work very well because it completely ignores price, which would not allow ‘business as usual’ to persist until 2100. An economic model known as the DICE model (Dynamic IntegratedModel of Climate and the Economy) looks at price. Economic models project rising relative energy prices and slowing economic growth in the coming decades; as a result, they tend to show lower emissions and temperature trends than the extrapolative approaches often used in the scientific community and demonstrated by the IPCC projections above (Nordhaus, 2005). The DICE models lesser projected increase of about 2 to 4.5 degrees C is still problematic and has an impact on economic systems
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