A level of no more than 350 ppm is still feasible, with the help of reforestation and improved agricultural practices, but just barely - time is running out.
James HansenBurning all the fossil fuels will destroy the planet we know, Creation, the planet of stable climate in which civilization developed.
James HansenWe're handing them [young people & future generations] a climate system which is potentially out of their control. We're in an emergency: you can see what's on the horizon over the next few decades with the effects it will have on ecosystems, sea level and species extinction
James HansenWhat has become clear from the science is that we cannot burn all of the fossil fuels without creating a very different planet.
James Hansen