Quote Originally Posted by Husar View Post
There is another "small" issue with the warming scenario in that it will become uncontrollable beyond a certain point as the permafrost begins to melt and sets free enormous amounts of stored methane, which is a 17 times stronger greenhouse gas than CO2, add to that the methane under arctic ice the limited ability of warm water to store CO2, the increase of water in the air, which also has a greenhouse effect...
Surely it may reverse after a few thousand years, but what do we do until then?
Methane is not stable in the atmosphere, and is converted into carbon dioxide in 8-9 years on average (it's also vulnerable to UV radiation, which is why its discovery on Mars is interesting):

In the lower part of the atmosphere, below about 10-12 km (the troposphere), the key cycles are mediated above all by the presence of what are called OH radicals — colloquially known as the atmospheric detergent. All hydrocarbon chemical species that are emitted can be eventually broken down (or oxidized) by these radicals to CO2 and H2O, and methane is no exception. An average molecule of CH4 lasts around eight to nine years before it gets oxidized. This is a long time compared to most atmospheric chemicals but is fast enough so that there can be significant year-to-year variability.
http://www.giss.nasa.gov/research/fe...00409_methane/

Thus, the direct effect of this methane should not last long as it comes from a storage that will deplete.