That type of runaway is not possible on the earth, because if the oceans boiled away the earth would be completely covered in cloud. This would raise the albedo from 0.3 to 0.9 and the planet would cool!
The real danger is that carbon dioxide will melt the Arctic sea ice. Then the conveyer will halt in the North Atlantic with two consequences. 1) CO2 will no longer be able to be so readily absorbed in that cold water so its atmospheric concenration will increase. 2) The cold water will no longer descend to the ocean floor allowing the methane hydrates to warm and release their methane. This seems to have happened before during the Triassic-Jurassic mass extinction and at the PETM methane "belch". So we may ge an extinction but not an extermination :-) Cheers, Alastair. On Dec 31 2009, 10:06 am, "[email protected]" <[email protected]> wrote: > http://bigthink.com/jameshansen/the-science-of-global-catastrophe > > "In the long run [...] over centuries, we could actually get a runaway > greenhouse effect, and then that's it for all the species on this > planet [...]. [R]unaway greenhouse effect means once the planet gets > warmer and warmer, then the oceans begin to evaporate.[...] [T]he > oceans will begin to boil, and the planet becomes so hot that the > ocean ends up in the atmosphere." > > Looking through the archives I found this thread: > http://groups.google.com/group/globalchange/browse_thread/thread/b113... > > How come I am posting on this now? Well, I saw a review in the New > Scientist of this > book:http://www.amazon.co.uk/Storms-My-Grandchildren-Catastrophe-Humanity/... > > http://www.newscientist.com/article/mg20427381.700-will-you-stand-up-... > > "James Hansen, is telling it as he sees it, and the result is the most > frightening book I have ever read, for three reasons. > > First, Hansen has come to believe, based on studies of past climate > change, that the threat facing us is far worse than he thought even a > few years ago. The very survival of life on Earth is at stake, he > says. The sun is 2 per cent brighter than it was just 250 million > years ago, and if we burn up all the fossil fuel on the planet - all > the oil, coal, tar sand and tar shale - we will trigger a runaway > greenhouse effect that will ultimately lead to the oceans boiling > away, he claims." -- You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/globalchange
