More recently still, however, and based on an analysis of conditions in the past derived from ocean bed sediments and ice cores, leading climatologists led by NASA\’s Jim Hansen have suggested that even 350 ppm might dangerous.
While the climate change sceptics and deniers comprise an ever-dwindling band, they are still undermining our last chance to deal with the climate change emergency. I\’m sure they\’ll be here again today, peddling the junk science of special interests and the ill-conceived, unreferenced and non-peer reviewed tripe loaded onto the websites from which they seek solace from the reality of global warming.
You are, of course, aware that the Jim Hansen paper is not peer reviewed? That it is a "pre-paper"? Further, that it is making very contentious (code for "no one else as yet agrees") points about climate sensitivity? Ones which very few indeed take seriously as yet?