Researchers Reveal the Worst Methane Super-Emitters in the U.S.

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When it comes to global warming, methane is a monster. It may represent only 11% of the share of greenhouse gasses emitted each year, but during its first 20 years in the atmosphere it is 80 times more efficient at capturing heat than the far more commonplace carbon dioxide. That’s why it’s so important to spot the worst emitters and shut them down—or at least reduce their output. Now, as NASA’s Jet Propulsion Laboratory (JPL) reports, researchers have taken a big step toward reaching that goal.

In a new paper in the Proceedings of the National Academy of Sciences, investigators from JPL, the University of Arizona, and Arizona State University, have pinpointed the point-sources of 40% of the worst methane emitters across the U.S. The investigators used two key tools to conduct their study: Arizona State’s Global Airborne Observatory (GAO), an imaging spectrometer carried aboard aircraft flying at 5,500 m (18,000 ft.) that can spot methane point-sources on the ground; and the European Space Agency’s Sentinel-5P satellite, which does the same job from orbit.

Using both of these eyes in the sky, the investigators identified over 3,000 individual methane super-emitters—defined as sites releasing more than 10 kg (22 lbs) of methane per hour. The emission sites include oil and gas production facilities, wet manure sites in animal feedlots, large landfills, and coal mines.

Identifying the sources, though, is not the same as shutting them down, and some are harder to control than others. As long as animals are bred for slaughter, for example, there will always be methane-emitting feed lots. On the other hand, the oil and gas industry can control the waste methane they produce in a number of ways. Currently, they dispose of most of the gas by flaring—essentially burning it off at the mouth of smokestacks—which simply vents it into the sky. Reinjecting it deep into well sites or collecting it for sale as natural gas would be better, far less-polluting alternatives. Better still, of course, would be reducing our dependence on fossil fuels overall, switching to clean renewable sources like wind and solar power.

This story originally appeared in TIME Space, our weekly newsletter covering all things space. You can sign up here.

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