A few weeks ago, NASA's chief climatologist, James Hansen, submitted a paper to Science magazine with several coauthors. The abstract attached to it argued -- and I have never read stronger language in a scientific paper -- that "if humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm."
As of October 2010, carbon dioxide in the Earth's atmosphere is at a concentration of 388 ppm by volume.
Growing, growing, growing ... gone?
