Guest Post by Willis Eschenbach
A recent study by Shindell et. al, entitled Improved Attribution of Climate Forcing to Emissions, (Science Magazine, 30 October 2009, Vol. 326) reports on interactions between aerosols and methane and other greenhouse gases. It has been discussed on Watts Up With That here <http://wattsupwiththat.com/2009/10/31/an-idea-i-can-get-behind-regulate-methane-first/>, as well as on other blogs. The Shindell study gives new values for the “radiative forcing” of various greenhouse gases. The “radiative forcing” is the increase in greenhouse radiation which is due to the increases in greenhouse gases since 1750.
UPDATE: The remainder of this article has been removed at the request of the guest author, Willis Eschenbach. During discussion, an error was discovered (see comments) and rather than leave this article with that error in place which may possibly mislead somebody in the future (if they didn’t read through comments) I’m honoring Willis’ request for removal. The comments remain intact. – Anthony
Gary Hladik (12:38:57) :
I’m just a guest contributor, I can’t edit it. I’ll ask Anthony to pull it, as the original premise has been shown to be false.
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Willis Eschenbach (20:17:18) :
After rising for a number of years, the atmospheric methane emissions have levelled off during the last decade. Nobody knows why this has happened. Heck, nobody knows why they were rising prior to levelling off. Nobody knows which way they will go from here.
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I remember from organic chemistry that UV light can break the C-H bond to form free radicals which are very reactive. Solar UV output has been going up. I wonder if that could account for the decrease in methane?
Solar UV
http://www.john-daly.com/hockey/solar.gif
Willis Eschenbach (14:27:54):
Thanks, Willis. Though the premise of the article was incorrect, and the original paper’s contribution “incremental”, the topic is a useful reminder of the complex chemical processes going on in our atmosphere.
In other words, “It’s more complicated than I thought!” 🙂
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Jim (15:40:23) :
I remember from organic chemistry that UV light can break the C-H bond to form free radicals which are very reactive. Solar UV output has been going up. I wonder if that could account for the decrease in methane?
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Correction, I was remembering the UV initiated reaction between chlorine and methane. The UV breaks the chlorine into two free radicals which then react with methane.