The U.S. may produce half again as much methane, a strong greenhouse gas, as has been thought, according to a study published this week in Proceedings of the National Academy of Sciences by Scot Miller, a doctoral student in earth sciences at Harvard University. If true, it would not be good news for energy and livestock producers, the main sources of methane released by human activities.
"In the atmosphere over some regions — Texas, Kansas and Oklahoma — the study found more than 2.5 times the methane that the EPA and other groups have measured," reports Christopher Joyce of NPR. The Environmental Protection Agency has usually estimated methane emissions by "plugging into a computer model, for example, the estimated individual outputs from all the nation's gas drilling sites, swamps, refineries and herds of cattle that belch and otherwise excrete the gas as a normal part of digestion. The new study — a collaboration of scientists from universities, the U.S. government and Europe — instead took almost 13,000 measurements directly from the atmosphere in 2007 and 2008. They collected their measurements from cell towers as tall as the Empire State Building, as well as from airplanes." The scientists "found that what's airborne is more than the sum of the ground measurements."
Duke University environmental scientist Rob Jackson told NPR that the "bottom-up measurements are lower because we miss the few percent of sites that are really leaking a lot of gases. We probably have 90 percent of oil and gas operations that are pretty clean, and a few percent that leak like a sieve." He said the higher levels in the south-central states "suggests that oil and gas operations there are emitting more methane than previously thought," Joyce writes.
UPDATE, Dec. 2: EPA administrator Gina McCarthy said of the study, "We intend to take a close look at it," Jason Plautz of Greenwire reports.
"In the atmosphere over some regions — Texas, Kansas and Oklahoma — the study found more than 2.5 times the methane that the EPA and other groups have measured," reports Christopher Joyce of NPR. The Environmental Protection Agency has usually estimated methane emissions by "plugging into a computer model, for example, the estimated individual outputs from all the nation's gas drilling sites, swamps, refineries and herds of cattle that belch and otherwise excrete the gas as a normal part of digestion. The new study — a collaboration of scientists from universities, the U.S. government and Europe — instead took almost 13,000 measurements directly from the atmosphere in 2007 and 2008. They collected their measurements from cell towers as tall as the Empire State Building, as well as from airplanes." The scientists "found that what's airborne is more than the sum of the ground measurements."
Duke University environmental scientist Rob Jackson told NPR that the "bottom-up measurements are lower because we miss the few percent of sites that are really leaking a lot of gases. We probably have 90 percent of oil and gas operations that are pretty clean, and a few percent that leak like a sieve." He said the higher levels in the south-central states "suggests that oil and gas operations there are emitting more methane than previously thought," Joyce writes.
UPDATE, Dec. 2: EPA administrator Gina McCarthy said of the study, "We intend to take a close look at it," Jason Plautz of Greenwire reports.
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