Wednesday, February 16, 2011

If climate models are correct, even if emissions stopped today we would get warmer

Science 2.0: There are varying levels of acceptance for various climate models, especially those that predict short-term escalation of warming due to man-made emissions. Given that, no one is going to like new University of Washington claims that it's already too late. People who want curbs on emissions won't like news that it won't help and people who don't think emissions are the biggest problem in a worldwide recession won't bother to listen if it doesn't matter.

But there is at least a glimmer of hope. While there would continue to be warming even if the most stringent policy proposals were adopted, because there still would be some emission of heat-trapping greenhouse gases such as carbon dioxide and methane, the claim that even if all emissions were stopped now, temperatures would remain higher than pre-Industrial Revolution levels because the greenhouse gases already emitted are likely to persist in the atmosphere for thousands of years has some room for interpretation - because accurate temperature records don't even go back 40 years much less 140 years.

But first, the bad news; Kyle Armour, a UW doctoral student in physics, says it is possible temperatures would continue to escalate even if all cars, heating and cooling systems and other sources of greenhouse gases were suddenly eliminated, because tiny atmospheric particles called aerosols, which tend to counteract the effect of greenhouse warming by reflecting sunlight back into space, would last only a matter of weeks once emissions stopped, while the greenhouse gases would continue on.

…In their best-case simulation, the global temperature would actually decline, but it would remain about a half-degree higher than pre-Industrial Revolution levels and probably would not drop to those levels again, Armour said. There also is a possibility temperatures would rise to 3.5 degrees F higher than before the Industrial Revolution, a threshold at which climate scientists say significant climate-related damage begins to occur. Far beyond what IPCC models have projected….

William Hamilton, "Prospero and Ariel," 1797

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