Here's another article. It's from Hansen but a little more technical:

Burning fossil fuels like coal is the chief cause of man-made greenhouse gases. Hansen said the Earth's atmosphere has got to get back to a level of 350 parts of carbon dioxide per million. Last month, it was 10% higher: 386.7 parts per million.
NASA warming scientist: 'This is the last chance'
June 24, 2008

WASHINGTON (AP) — Exactly 20 years after warning America about global warming, a top NASA scientist said the situation has gotten so bad that the world's only hope is drastic action.


James Hansen told Congress on Monday that the world has long passed the "dangerous level" for greenhouse gases in the atmosphere and needs to get back to 1988 levels. He said Earth's atmosphere can only stay this loaded with man-made carbon dioxide for a couple more decades without changes such as mass extinction, ecosystem collapse and dramatic sea level rises.

"We're toast if we don't get on a very different path," Hansen, director of the Goddard Institute of Space Sciences who is sometimes called the godfather of global warming science, told The Associated Press. "This is the last chance.
Link & Entire: http://www.usatoday.com/tech/science...g_N.htm?csp=34