A handful of climate stuff

James Hansen is starting to look more and more prescient: in his 2007 article "Trace gases and Climate Change", he argued that previous estimate of climate sensitivity (how vulnerable the Earth's climate was to CO2 levels) understated the dangers because they failed to take in to account long-term feedbacks. He argued that a proper estimate of long-term feedbacks would add at least one degree to the 3-4 degrees of expected warming from doubling of CO2 in the atmosphere. An independent British investigation has come to much the same conclusion.

Oh, how I wish President Gore had been allowed to take office.

If you'd like some depressing reading, check out the Copenhagen Diagnosis. It basically tracks with the estimate of the German report I mentioned a few weeks ago:

If global warming is to be limited to a maximum of 2 °C above pre-industrial values, global emissions need to peak between 2015 and 2020 and then decline rapidly. To stabilize climate, a decarbonized global society – with near-zero emissions of CO2 and other long-lived greenhouse gases – needs to be reached well within this century. More specifically, the average annual per-capita emissions will have to shrink to well under 1 metric ton CO2 by 2050. This is 80-95% below the per-capita emissions in developed nations in 2000.

The 2-degree guardrail may still not be enough -- a warming of 2 degrees globally implies much more warming over Greenland and West Antarctica, perhaps sufficient (the authors say) to eventually melt the Greenland ice sheet and raise sea level by 6m or more.

I'll reserve judgment to see what happens in Copenhagen, but it's worth noting that even if the governments of the world meet their current commitments, they'll still be committing us to at least 3 degrees of warming, enough at the poles to put polar ice at serious, serious risk. And remember that Antarctica is already looking unstable.