UC Irvine TODAY UC Irvine homepage UC Irvine TODAY

UC Irvine TODAY

News

News

Thursday, July 31, 2014

News Release

Email this page to a friend EmailPrinter friendly page PrintShare Share

Sky-high methane mystery closer to being solved, UCI researchers say

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

— Irvine, Calif., August 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 agricultural activity, 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 fuel source, which sharply reduced the skyward venting and flaring of methane from oil fields. 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 potent greenhouse gas, second in importance only to carbon dioxide. We can’t make real progress on climate change 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 rice paddies 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.

Other authors are Simone Meinardi, Nicola Blake and F. Sherwood Rowland (posthumous) of UCI; Lori Bruhwiler of the National Oceanic & Atmospheric Administration; and Detlev Helmig of the University of Colorado. Funding was provided by NASA.

About the University of California, Irvine: Founded in 1965, UCI is a top-ranked university dedicated to research, scholarship and community service. Led by Chancellor Michael Drake since 2005, UCI is among the most dynamic campuses in the University of California system, with nearly 28,000 undergraduate and graduate students, 1,100 faculty and 9,000 staff. Orange County’s second-largest employer, UCI contributes an annual economic impact of $4 billion. For more UCI news, visit www.today.uci.edu.

News Radio: UCI maintains on campus an ISDN line for conducting interviews with its faculty and experts. Use of this line is available for a fee to radio news programs/stations that wish to interview UCI faculty and experts. Use of the ISDN line is subject to availability and approval by the university.

methane graph
Rowland-Blake Group, UC Irvine
The figure shows the long-term decline of the global concentration of atmospheric ethane (blue line), which closely matches the long-term decline of the global growth rate of atmospheric methane (pink line). This association clearly shows that fossil fuel reductions are probably responsible for a significant portion of methane’s long-term decline. This data set represents the longest continuous record of global atmospheric ethane levels.

Media Contact

Janet Wilson
University Communications
949-824-3969
janethw@uci.edu

Experts Available

UCI maintains an online directory of faculty available as experts to the media.
University of California, Irvine
University of California, Irvine - Irvine, CA 92697 : 949-824-5011
Comments & Questions | Privacy & Legal Notice | Copyright Inquiries | © 2014 UC Regents