In this fascinating, accessible presentation, James Hansen, one of our most respected climate scientists, argues that we’re much closer to “dangerous anthropogenic interference” than the IPCC’s work would suggest: “The dominant issue in global warming, in my opinion, is sea level change and the question of how fast ice sheets can disintegrate. A large portion of the world’s people live within a few meters of sea level, with trillions of dollars of infrastructure. The need to preserve global coast lines, I suggest, sets a low ceiling on the level of global warming that would constitute DAI.” The funny thing is the Hansen is still an optimist. Or, rather, he thinks we still have time. Just. This one is a must read.