CLIMATEGATE » Anthony Watts http://www.climategate.com Anthropogenic Global Warming, history's biggest scam Sat, 17 Jul 2010 22:20:21 +0000 en hourly 1 http://wordpress.org/?v=3.0.4 Is the effect of Carbon Dioxide on temperature logarithmic? http://www.climategate.com/is-the-effect-of-carbon-dioxide-on-temperature-logarithmic http://www.climategate.com/is-the-effect-of-carbon-dioxide-on-temperature-logarithmic#comments Mon, 08 Mar 2010 08:38:32 +0000 Anthony Watts http://wattsupwiththat.com/?p=17114 too successful at reducing greenhouse gases? Can we actually calculate the correct amount by which to reduce, and what would happen to temperatures? Would a 1% reduction in CO2, for example, reduce temperatures by 1%.]]> Warmers talk incessantly, and catastrophically, about the need to reduce greenhouse gases. If the greenhouse gases in the atmosphere rise, so does the temperature, and soon enough we will all die, they say. But what would happen if the reverse were to occur? What if we were too successful at reducing greenhouse gases?  Can we actually calculate the correct amount by which to reduce, and what would happen to temperatures? Would a 1% reduction in CO2, for example, reduce temperatures by 1%.

No. Too much of a reduction could actually be quite — to use their the warmers second favorite word (the first is “settled”) — catastrophic.

David Archibald, writing for Watts Up With That today, tells us that the relationship isn’t linear, it’s logarithmic:

The greenhouse gasses keep the Earth 30° C warmer than it would otherwise be without them in the atmosphere, so instead of the average surface temperature being -15° C, it is 15° C. Carbon dioxide contributes 10% of the effect so that is 3° C. The pre-industrial level of carbon dioxide in the atmosphere was 280 ppm. So roughly, if the heating effect was a linear relationship, each 100 ppm contributes 1° C. With the atmospheric concentration rising by 2 ppm annually, it would go up by 100 ppm every 50 years and we would all fry as per the IPCC predictions.

But the relationship isn’t linear, it is logarithmic. In 2006, Willis Eschenbach posted this graph [charts at WUWT] on Climate Audit showing the logarithmic heating effect of carbon dioxide relative to atmospheric concentration. I recast Willis’ first graph as a bar chart to make the concept easier to understand to the layman:

Lo and behold, the first 20 ppm accounts for over half of the heating effect to the pre-industrial level of 280 ppm, by which time carbon dioxide is tuckered out as a greenhouse gas. One thing to bear in mind is that the atmospheric concentration of CO2 got down to 180 ppm during the glacial periods of the ice age the Earth is currently in (the Holocene is an interglacial in the ice age that started three million years ago).

Plant growth shuts down at 150 ppm, so the Earth was within 30 ppm of disaster. Terrestrial life came close to being wiped out by a lack of CO2 in the atmosphere.

There is much more to this article, so head over to WWUT and read it all. I perused the comments and see that not all readers seem so sure that this theory holds water. What’s your opinion?

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