In reply to Horace Heffner's message of Mon, 8 Sep 2008 09:12:24 -0800: Hi, [snip] >The immediate problem is passing the tipping point where the methane >is released.
The tipping point is presumably when the temperature rises above zero deg C and the ground starts to melt. Since the permafrost has already started melting in Siberia, the process has already begun. That means we are now in a race against the clock. Not only do we need to reduce CO2, we need to do it fast enough to actually drop the temperature back below freezing so that the methane production stops. >Methane is 20 times more effective than CO2 at the >greenhouse effect, and is lighter than air. It eventually oxidizes >into CO2, but at high altitude. High altitude water vapor is a very >effective greenhouse gas, and at some point the more you get the more >you get. Even low altitude water vapour is an effective greenhouse gas, despite the fact that it "rains out" regularly. >If we get enough of it we're permanent toast - fully burnt >toast at that. The oceans will boil off and the surface of the earth >will likely end up over 200 deg. C. Welcome to New Venus. If the oceans were to boil off, where would all the water to go? Besides, there is also the "evaporative cooler" effect. The faster the hydrological cycle takes place, the more rapidly heat is removed. I think this is the major negative feedback effect. Also increasing rainfall tends to dissolve more CO2 and carry it into the oceans. Though I don't know how close they are to saturation (another tipping point), though I suspect that they are already effectively in balance with the CO2 in the atmosphere. There is also the possibility that increasing geothermal action will release the methane from the clathrates (and they want to put CO2 down there too???). Regards, Robin van Spaandonk <[EMAIL PROTECTED]>
