Settled science: The earth will warm 2 to 20 degrees. Or it'll cool. Or it will repeatedly warm and cool

Climate Change and 'Balanced' Coverage - NYTimes.com

The true worst case from doubled carbon dioxide is closer to 18 or 20 degrees of warming, Dr. Alley said — an addition of heat so radical that it would render the planet unrecognizable to its present-day inhabitants.

Dr. Alley calls the usual news media presentation of the issue a form of “false balance.” In his view, mainstream climate science should be seen as coming down on the conservative side of a range of numbers that runs from 2 degrees to 20 degrees. And in setting public policy, he said, lawmakers need to entertain the possibility that any of these numbers is correct.