global average temperatures

Yale Study: Earth's climate appears more sensitive to CO2 than previously thought

 rm iwest mugRichard Harris' NPR story this week exploring how global temperatures stayed pretty constant over the last decade even as greenhouse gas concentrations increased reminded me of another important piece of research overlooked during last month's global climate negotiations in Copenhagen:

Yale University researchers studying past warming episodes that didn't get any help from the Industrial Revolution say the climate may be more sensitive to carbon dioxide than we previously understood.

The study by Yale's Climate and Energy Institute found that about 4.5 million years ago, when the concentration of CO2 in the atmosphere was roughly what it is today, global temperatures were 2 to 3 degrees Centigrade higher. This is a pretty big deal, recall, because we're talking about global average temps. The extremes are higher and the effects are more far-reaching than, say, a simple bump in the mercury on a summer day of 2 to 3 degrees might suggest.

The big message is sobering.