There'll be a hot time on the old planet soon

“There’s a parade of world leaders standing up here today and speaking on and on and on about proposals that’ll keep us below 2 degrees and pretending that the stuff on the table has any hope of doing that. And the U.N. itself knows that it’s going to go at least 50 percent hotter than they’re pretending.”

Bill McKibben as reported by Dot Earth Blog

350 ppm [parts per million of carbon dioxide in the atmosphere] is being considered in Copenhagen as the threshold for disaster. That is expected by most to lead to a 2ºF rise in temperatures and a disaster. A new U.N. document indicates we are well are on way to 550 ppm and a 5.4ºF rise.