Many scientists are now warning that we are moving closer to several "tipping points" that could — within as little as 10 years — make it impossible for us to avoid irretrievable damage to the planet's habitability for human civilization. In this regard, just a few weeks ago, another group of scientists reported on the unexpectedly rapid increases in the release of carbon and methane emissions from frozen tundra in Siberia, now beginning to thaw because of human caused increases in global temperature. The scientists tell us that the tundra in danger of thawing contains an amount of additional global warming pollution that is equal to the total amount that is already in the earth's atmosphere.

NYU Law School speech (2006)