For a more accurate representation of climate over the last 100 Million years, there is an excellent video of a lecture by Prof Richard Alley at the Fall AGU meeting where he talks about the Permian and Cretaceous temperatures. http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml

Thanks for the comment. I replied to that post, and several like it, here:http://theamericanscene.com/2009/06/30/money-is-not-the-measure-of-all-things

Yes, that irony was one thing I really wanted to emphasize.

JD Will:

That is exactly the kind of comment that I love to hear, thanks. There’s an old saying in physics: “If you can’t explain it simply, you don’t understand it well enough”.

I’m be pretty skeptical of outlier conclusions because I know enough about other areas of science to know I’m not competent t judge theories in this speciality, outside of some very limited domains.

Nate Silver (no relation) published a response to this argument in June, looking at the contribution to Global GDP of the nations that would likely be most affected by climate change .

“The problem with GDP is this: it varies greatly across counties, by a factor of 800 or so on a per-capita basis between Burundi and Luxembourg, or nearly 2,000 if you count Zimbabwe, which effectively does not have an economy. A lot of countries contribute almost nothing to global GDP, even though they may have tens or hundreds of millions of people. You could literally wipe them from the globe and the impact on global GDP would be de minimis.”

http://www.fivethirtyeight.com/2009/06/how-to-destroy-almost-half-planet-for.html

http://eggplantpost.com/2009/12/16/tom-friedman-checks-into-five-star-hotel-gets-idea-for-new-book/

One point to add. There is likely an upper limit to temperature as CO2 increases. This paleo record (scroll down)
http://www.geocraft.com/WVFossils/Carboniferous_climate.html
shows temperature flat lining at about 22 degrees Celsius even when CO2 was much higher than today. Of course as with any ‘facts’ it is hard to correlate this to graphs at the .gov or AGW proponent sites, so I am still looking for other sources.

That’s only 71 F, and enquiries to geologist sites indicate there would be less gradient. Evidently the hothouse earth in the deep past was possibly balmy – life certainly flourished in these periods.

Back on your main point, all these projections depend fundamentally on climate sensitivity to forcing from CO2 (and other inputs). This following article is quite interesting in Dr Nir Shaviv claims to be able to empirically calculate sensitivity based on past record.
http://www.sciencebits.com/OnClimateSensitivity

“The IPCC states … the climate sensitivity is likely to be in the range of 1.5 to 4.5°K. ” – (for CO2 doubling)

Whereas he derives:

“ … corresponds to CO2 doubling temperature of 2.0±0.5°K. ” – (excluding his pet theory, CRF, which takes it much lower)

My current take away is the tails aren’t that fat and though we should be working on new and improved energy, we should not beggar ourselves with Friedman’s ‘insurance policy’.

Simultaneously we are continually hectored about how the excess costs of medical care in the US represent a danger to our republic.

Why is it that paying too much for low quality energy is good but paying too much for high quality health care is bad? Which one does more damage to the economy?