CHAIRMAN KERRY: We are cushioned between the tipping point that scientists have warned us of, the two degrees centigrade and we have to achieve 350 ppm which is the goal that most scientists believe will result in stability, is that correct? MR. GORE: That is the goal that I support, and that is my reading of what I believe is the best science. I think that an accurate picture of the science is that leading researchers like Professor Jim Hansen, like Dr. Jim Hansen at NASA have now begun to coalesce around the strong feeling that 350 is the appropriate goal. After years of debate within an international political framework other scientists have despaired about the ability of the political system to do what the science mandates and have coalesced around 450, some even 550, but the more the evidence comes in the more it becomes increasingly apparent that 350 is the appropriate goal. If we are at 386 now and the entire north polar ice cap is completely melting in five years and both Greenland and Antarctica are at risk, obviously we need to be below the level we are at now.
— http://www.350.org/en/about/blogs/al-gore-testifies-us-congress
