Re: [asa] Rush Limbaugh Science Lesson

Another matter of confusion in claims that global warming isn't a bit
deal is the misconception that absolute temperature is the issue.
Although some organisms are close enough to tolerance limits that high
temperatures may be fatal, the main problem for organisms, including
humans, is the exceptionally rapid rate of change. Global
temperatures and CO2 levels have been a lot higher in the geologic
past (though there are extinctions associated with big changes). With
a slow change, many organisms would be able to either migrate away
from the equator or up mountains or else evolve to match the new
conditions.

There are various features of organisms and geochemical tracers that
appear to reflect CO2 levels, which can be measured in the geologic
record. Not nearly as precise or accurate as air bubbles in ice, but
it gives a general idea.

However, we're likely to run out of petroleum before global warming
gets extreme. Economic ramifications of that might catch the
attention of politicians sooner than the environmental effects of
warming.

-- 
Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"
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