There is an interesting paper out in Nature today (don't send me it, I've just discovered we have Nature online from work, how nice; if you too have access, the article is here and the commentaries here and here: so I've downloaded the pdfs into my computer but not yet into my brain). In the meantime I will of course recomment to you the RealClimate take: Scientists Baffled. I will strongly disrecommend the Grauniad's stupid Global warming: blame the forests; the BBC's Plants revealed as methane source is a bit better.
The point being that this (if true) is a change to the methane source (by up to 30%) but CO2 is a bigger forcing that the total methane; and of course the total methane levels in the atmosphere remain what they have always been measured to be, so historical forcing estimates from total methane remain unchanged. Perhaps the attribution will change a little bit: though to first order we have lost forest over the last century I think, so if plants are a net source that means we've been losing plant sources which means (given that we know the absolute levels) that anthro methane sources have grown more than previously believed...
http://www.cbc.ca/quirks/archives/05-06/jan14.html
ReplyDeleteQuirks and Quarks on CBC Radio did an interview with Dr. David Lowe on this subject on Saturday. You might find it interesting to listen to.
Look for the story "Plants and Methane" at the bottom of the webpage.