However, we can deduce the role of methane feedback by looking at past climate change. (skepticalscience.com)
Update 7 Mar 2010: Real Climate offer some good perspective on methane feedback which echoes the theme in CO2 is not the only driver of climate: (skepticalscience.com)
We need to avoid inciting a really sizable methane feedback, if at all possible. (realclimate.org)