Commercial natural gas was likely major factor in late-20th century stabilization

Aug 22, 2012

Increased capture of natural gas from oil fields probably accounts for up to 70 percent of the dramatic leveling off seen in atmospheric methane at the end of the 20th century, according to new UC Irvine research being published Thursday, Aug. 23, in the journal Nature.

"We can now say with confidence that, based on our data, the trend is largely a result of changes in fossil fuel use," said chemistry professor Donald Blake, senior author on the paper.

Methane has 20 times the global warming potential of carbon dioxide, although CO2 is filling the atmosphere in far larger amounts. After decades of increases due to worldwide industrial and , the tapering off of methane from the 1980s through 2005 was remarkable. Scientists have long wrestled with the cause.

Blake and his team, who have conducted the world's longest continuous methane and ethane sampling, said close scrutiny of their data shows that the major factor was most likely the trapping and sale of natural gas for use as a , which sharply reduced the skyward venting and flaring of methane from . Methane is the main ingredient in natural gas.

"It used to just be burned off as a waste product," said lead author Isobel Simpson, a UCI research associate. "The reason this is important is because methane is a , second in importance only to carbon dioxide. We can't make real progress on without tackling carbon dioxide, but bringing methane under control would certainly help."

Since 2007, levels have started to climb again, adding urgency to the scientific mystery. Many researchers have tried to determine what prompted the decline, including others at UCI. Last summer, a pair of papers in Nature offered different causes: less natural gas from oil fields in one case and changing fertilizer and water practices in in the other. Blake said his group had confirmed – using comprehensive global measurements – that the former was probably the major factor.

For nearly 30 years, successive generations of UCI chemistry students and researchers have filled canisters with air samples at remote locations across the globe. The breadth and length of that sampling proved invaluable in solving the methane puzzle, said one.

"This paper speaks to the importance of scientific insight that only can be gained from decades of meticulous, sustained data recording," said co-author Mads Sulbaek Andersen, formerly of UCI and now with NASA's Jet Propulsion Laboratory.

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User comments : 7

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Caliban
3 / 5 (4) Aug 22, 2012
Seems reasonable, at least on its face.

But it also seems reasonable to assume that methane capture(in the form of natural gas) has continued at more or less the same rate, if not having actually increased over previous capture rates.

So wherefore the uptick in emissions since '07? Fracking? Arctic warming? Near-shore clathrate melting?

A question in serious need of answering.

Howhot
4.2 / 5 (5) Aug 22, 2012
I'm going to say "Near-shore clathrate melting" as the primary cause. All you have to do is google-earth the eastern and northern edge of Russia to see lake after lake, pond after pond of tundra-ice melt. Thousands of them. The geology is fascinating. But you can imagine each one as a methane trap releasing it's store of methane as temperatures increase in the Northern latitudes.

NotParker
1 / 5 (5) Aug 23, 2012
Looks like CH4 leveled off and stayed leveled off.

http://www.eea.eu...-ch4-ppb

"Methane was steadily increasing in the 1980's, it's growth rate slowed in the 1990's, and it has had a near-zero growth rate for the last few years."

http://www.esrl.n...ane.html

One of the major sources of methane is sewage treatment facilities and garbage dumps. And many large dumps now capture the methane and burn it for power.

http://articles.l...20100814
NotParker
1 / 5 (3) Aug 23, 2012
"The number of landfill gas projects, which convert the methane gas that is emitted from decomposing garbage into power, went from 399 in 2005 to 519 in 2009 according to the Environmental Protection Agency"

"Of the roughly 450 landfill gas projects operational in 2007, 11 billion kWh of electricity was generated and 78 billion cubic feet of gas was supplied to end users. These totals amount to roughly 17,500,000 acres (71,000 km2) of pine or fir forests or annual emissions from 14,000,000 passenger vehicles"

http://en.wikiped...lization
NotParker
1 / 5 (3) Aug 23, 2012
EPA says methane produced by landfill dropped from 147.4 TgCO2 Equivalents in 1990 to 117.5 in 2009.

http://epa.gov/me...ces.html
Howhot
5 / 5 (1) Aug 23, 2012
Of course you would say that NP. Interesting links but that is counter to what the article says:
Since 2007, levels have started to climb again...
levels of methane of course. The mystery they were trying to resolve was why did methane taper off from 1980 to 2005?

It seems obvious to me, that an intervention in the production of
methane occurred during time frame, and the redirection and use of methane from land fills and oil fields was the cause of the slow down and leveling off of methane creation. Assuming that processes is still continuing (as you noted in the drop of methane from landfills), then something mysterious is occurring that has increased methane in the atmosphere since 2007.

With the melting of the permafrost and northern shore ice from global warming, I think its very possible the new sources of methane are from those areas. If the methane is concentrated in the northern hemisphere that would implicate Siberia, Alaska and Canada's northern tundra.
NotParker
1 / 5 (3) Aug 24, 2012
I wonder why methane went down when the global average temperature scam insisted it was warming.

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