Research and Application News
NASA-led study solves a methane puzzle
02 January 2018
A new NASA-led study has solved a puzzle involving the recent rise in atmospheric methane, a potent greenhouse gas, with a new calculation of emissions from global fires. The new study resolves what looked like irreconcilable differences in explanations for the increase.
Methane emissions have been rising sharply since 2006. Different research teams have produced viable estimates for two known sources of the increase: emissions from the oil and gas industry, and microbial production in wet tropical environments like marshes and rice paddies. But when these estimates were added to estimates of other sources, the sum was considerably more than the observed increase. In fact, each new estimate was large enough to explain the whole increase by itself.
Scientist John Worden of NASA's Jet Propulsion Laboratory in Pasadena, California, and colleagues focused on fires because they're also changing globally. The area burned each year decreased about 12 percent between the early 2000s and the more recent period of 2007 to 2014, according to a new study using observations by NASA's Moderate Resolution Imaging Spectrometer satellite instrument. The logical assumption would be that methane emissions from fires have decreased by about the same percentage. Using satellite measurements of methane and carbon monoxide, Worden's team found the real decrease in methane emissions was almost twice as much as that assumption would suggest.
Image credit: NASA/GSFC/SVS - A reduction in global burned area in the 2000s had an unexpectedly large impact on methane emissions.