Runaway Greenhouse Effect - Earth

Earth

Earth's climate has swung repeatedly between warm periods and ice ages during its history. In the current climate the gain of the positive feedback effect from increased atmospheric water vapor is well below that which is required to boil away the oceans. Climate scientist John Houghton has written that " is no possibility of runaway greenhouse conditions occurring on the Earth". However, climatologist James Hansen disagrees. In his Storms of My Grandchildren he says that burning coal and mining shale oil will result in runaway greenhouse on Earth.

Benton and Twitchett's have a different definition of a runaway greenhouse; events meeting this definition have been suggested as a cause for the Paleocene-Eocene Thermal Maximum and the great dying.