The U.S. EPA dramatically underestimates the planet-heating impact of methane pollution, a study published Wednesday in Environmental Research Letters, finds. The agency’s current method for evaluating the heat-trapping impact of the main component of so-called “natural gas” fails to account for its near-term impact, the research report says, by using an “arbitrary and unjustified” 100-year timeline despite the fact that methane only stays in the atmosphere for about 12 years.

The 100-year time frame was used because Kyoto Protocol negotiators settled on it as a compromise between 20- and 500-year time frames and has massive implications for assessing the climate impact of methane pollution. As a heat-trapping gas in the atmosphere, methane is 81 times more potent than CO2 over a 20-year period, but just 28 times more potent over a 100-year period. “It’s a huge swing in how much we value methane, and therefore how many of our resources go towards mitigating it,” Sam Abernethy, a Stanford doctoral student and the lead author of the study, said. (Inside Climate News,