US methane emissions are higher than reported


I know, I know. I keep hitting NMID readers with studies lately.

There is so much work being done out there in the wide world—as people study everything from emissions to warming trends—that it would be a shame for New Mexicans to miss out on all this important information. Especially since many recent papers relate directly to the Land of Enchantment: our groundwater, the drier climate, declines in river flows, and the impacts of warming on snowpack and water supplies.

Now, a study coming out of Harvard shows that the United States is emitting more methane than previously thought.

The U.S. Environmental Protection Agency’s Greenhouse Gas Inventory, which has estimated and calculated reported emissions in the U.S. since 1990, shows that methane emissions have not increased significantly over the past decade.

But according to the new study, which relies on satellite images and surface observations, methane emissions increased by more than 30 percent between 2002 and 2014.

That increase, write the authors, could account for 30 to 60 percent of the global growth in methane over the past decade.

The trend is most obvious in the central portion of the US, though the emissions can’t be attributed to specific sources at this time.

Why does this matter to New Mexicans?

Aside from the fact that methane emissions contribute to the planet’s warming—and the southwest’s rapid warming—it’s been well-known for more than a year that New Mexico has its own methane problem.

In late 2014, NASA and others reported that a large methane plume was hovering above the Four Corners.

In the spring of 2015, scientists and state officials from Colorado and New Mexico hosted a public science forum to talk about the methane hotspot and ongoing studies to determine where it might be coming from. Natural sources of methane include wetlands and coal beds; human-caused sources include oil and gas infrastructure, livestock, coal mines, wastewater treatment plants, and landfills.

You can read those presentations online.

The recent study, “A large increase in US methane emissions over the past decade inferred from satellite data and surface observations,” was published earlier this month in the peer-reviewed “Geophysical Research Letters,” a peer-reviewed journal of the American Geophysical Union. To read the pre-publication version of the paper, visit here.