A study by the National Aeronautics and Space Administration (NASA) found that methane emissions from California's oil and natural gas operations are improving, but some environmental groups are skeptical of those conclusions.

NASA surveys from 2016 through 2018 found that waste management is the largest methane point source emission sector in California, accounting for 41% of the study’s total. Methane point source emissions from manure management at large dairies and the oil and gas sector each contributed about 26% of emissions in the study, which was published in the journal Nature.

The NASA team identified more than 550 individual point sources emitting plumes of highly concentrated methane. About 10% of those sources, considered super-emitters, contributed about a third of California’s total methane budget, according to the report.

Also this month, Our Nation's Energy Future (ONE Future) released its annual reporting of national methane intensity readings. For 2018, the coalition registered a methane intensity number of 0.326%, a decrease of 41% from the 2017 reading of 0.552%.

Richard Hyde, director of ONE Future, said the results verify that industry efforts to reduce emissions are working "more rapidly than anyone had originally thought possible."

But environmental groups, including the Environmental Defense Fund (EDF), are skeptical of such reports. EDF said its own emissions work over the 2012-2018 period indicates that "methane leaks in the United States are a far greater threat than the [federal] government's estimates suggest."

While the U.S. Environmental Protection Agency (EPA) has estimated national methane emissions at 8 million metric tons (mmt) annually, EDF said its research identified up to 13 mmt, 60% higher than the EPA data. "This giant discrepancy renews our commitment to tackle methane pollution that threatens the climate as the Trump administration attempts to erode protections and the EPA itself," said EDF.