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The Methane Mystery:

Over the past few decades, atmospheric methane levels have stopped increasing and leveled off. This is significant because methane is a particularly potent greenhouse gas, significantly more so than carbon dioxide. The question is what accounts for this trend, and whether it will continue. An article in the November/December issue of American Scientist discusses the mysterious trend and various potential implications.

This happy development wasn't entirely unanticipated, given that the rate of increase has been slowing for at least a quarter-century. Yet the United Nations Intergovernmental Panel on Climate Change has predicated many of its conclusions on scenarios in which methane concentrations would continue growing for decades to come. Thus the recent stabilization of methane levels is something that some scientists are trying very hard to explain.

If current trends continue, then the emission projections embodied in the IPCC's climate projections are significantly overstating the contribution of atmospheric methane to future warming. (Other analysts have suggested the IPCC has grossly overestimated future contributions from CO2, by overestimating likely future CO2 emission trends as well.) All this makes answering the methane industry of more than mere academic import.

SL (mail):
One reason for the levling off of methane in the atmosphere could be that we are doing a better job of capturing methane before it escapes into that atmosphere. Hardly a day goes by that the news doesn't have an article about a landfill, sewage plant, dairy farm or feedlot somewhere that is installing a system to catch an use the methane produced. Also, the oil and gas industry is probably deacreasing the amounts of gas released into the air.
12.4.2006 4:16pm
Daniel Chapman (mail):
Not to mention, we're doing a better job of getting rid of all those pesky, global-warming-causing trees.
12.4.2006 4:18pm
Ignorance is Bliss:
I've stopped eating at Taco Bell, that's cut down my contribution significantly
12.4.2006 7:23pm
Crunchy Frog:
How do you catch and use methane produced by dairy cows? (Okay, I can imagine, but it's just too disturbing to think about.)
12.4.2006 7:46pm
Tom Tildrum:
Maybe they're just feeding the cows less fiber.
12.4.2006 8:06pm
Dick King:
Crunchy Frog, I think a lot of the methane emitted as a result of cow digestion is emitted after the material leaves the cow.

However, we can maybe do something about the methane that gets released before the cow is done.

-dk
12.4.2006 9:36pm
airlawyer:
When cow manure decomposes, it releases methane. Cattle farms trap and use this methane in anaerobic digesters, which are simply big enclosed areas containing bugs that speed the break down of the manure. The gas is captured and burned to generate electricity or to heat other processes. Other than the value of the gas/electricity, owners of these digesters can now also sell their greenhouse gas reduction credits on the Chicago Climate Exchange.
12.5.2006 9:57am