Global Warming vs Nuclear Winter

I don't think the question is whether global warming exists...it does in some form exist, but the question breaks down into several vital parts-

1-How rapidly are climates changing?

2-Is pollution impacting the change?

3-How much more radical will the change become over the next 100 years?

All 3 of these questions affect each other, but #2 is the talking point of the day. I think the offical .gov site explains the complexity of this issue best-

Since the Industrial Revolution (around 1750), human activities have substantially added to the amount of heat-trapping greenhouse gases in the atmosphere. The burning of fossil fuels and biomass (living matter such as vegetation) has also resulted in emissions of aerosols that absorb and emit heat, and reflect light.

The addition of greenhouse gases and aerosols has changed the composition of the atmosphere. The changes in the atmosphere have likely influenced temperature, precipitation, storms and sea level. However, these features of the climate also vary naturally, so determining what fraction of climate changes are due to natural variability versus human activities is challenging.

There has been substantial natural climate change throughout history. Bear in mind we live on a planet that has more than likely experienced the rapid creation of land masses, an entire ice age, and countless natural enviromental changes throughout its long history. So it stands to reason that small changes in temperature are minimal in the overall scope of things.

Here's a projection from the site-

Carbon dioxide concentrations (see Figure 2) in the atmosphere will increase throughout the 21st century according to all IPCC scenarios. The scenarios project CO2 concentrations ranging from 540 to 970 parts per million (ppm) by 2100, which is 42 to 156 percent higher than current levels (IPCC, 2001).

Now for the practical stuff-

Temperature Change Projections

The National Academy of Sciences noted that because there is considerable uncertainty in current understanding of how the climate system varies naturally and reacts to emissions of greenhouse gases and aerosols, current estimates of the magnitude of future warming should be regarded as tentative and subject to future adjustments (either upward or downward). (NRC, 2001) The Intergovernmental Panel on Climate Change (IPCC) made the following projections of future warming (IPCC, 2001):

• The average surface temperature of the Earth is likely to increase by 2.5 to 10.4°F (1.4-5.8°C) by the end of the 21st century, relative to 1990 (see Figure 1). This projected rate of warming is about two to ten times greater than the warming observed during the 20th century and may represent a warming rate unprecedented for at least the last 10,000 years.
• Warming will not be evenly distributed around the globe:
  • Land areas will warm more than oceans in part due to water's ability to store heat.
  • High latitudes will warm more than low latitudes in part due to positive feedback effects from melting ice (as discussed above).
  • The northernmost regions of North America, and northern and central Asia, could warm substantially more than the global average. In contrast, projections suggest that the warming will be less than the global average in south Asia and southern South America.
• The warming will differ by season with winters warming more than summers.
• For additional explanatory information about some of the projected spatial and seasonal differences in warming, see the NOAA Geophysical Fluid Dynamics Laboratory (GFDL) fact sheet "Patterns of Global Warming" (PDF, 1 pp., 15 KB, About PDF)

Figure 1: Temperature projections, Source: IPCC Third Assessment Report (2001)

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The Earth's Commitment to Warming

According to several recent studies, even if the composition of today's atmosphere was fixed (which would imply a dramatic reduction in current emissions), surface air temperatures would continue to warm (by up to 1ºF). The studies suggest that a portion of the warming associated with past human activity has not yet been realized due to heat being stored in the ocean, and that the Earth is committed to continued warming. In addition, many of the greenhouse gases that have already been emitted remain in the atmosphere for decades or longer, and will continue to contribute to warming for their duration.

Now, that's the EPA side of things. I remain fairly neutral on this subject-I don't consider myself qualified to make any assumptions, I do however question the logic that these tiny changes to the earth's temperature are a:) going to create a rapid, permenant change in our climate as we know it and b:) warrant an immediate change in lifestyle. I am personally content with the efforts that car manufactures and groups like the EPA are making. I'm not selling my SUV, in other words.

/long post