Coal mines already emit more methane than venting and flaring at all the world’s oil and gas wells, and that impact could increase by more than 20% if all the new mines now on the drawing boards are built, warns a new report this week by Global Energy Monitor (GEM).

The industry already emits 52.3 million tonnes of the climate super-pollutant per year, about one-third more than oil and gas, Reuters reports. That means coal mining, by far the largest share of it taking place in China, exceeds the impact of the carbon dioxide released by the country’s 1,100 coal-fired power plants, Inside Climate News writes.

Those emissions could increase by another 11.3 million tonnes per year if a flurry of new coal mine construction is completed. “The coal age may be ending but methane emissions from new and operating mines may pose just as big a threat to the climate currently as oil or gas emissions,” said GEM research analyst Ryan Driskell Tate, author of the survey of about 2,300 operating coal mines around the world.

GEM released the report just days after Ernie Thrasher, CEO of Xcoal Energy & Resources, told an industry conference the market price of coal had increased tenfold, from US$50 to $500 per tonne, over the last two months.

“There’s just not enough to go around,” he said. “People are scrambling.”

Methane is more than 80 times more potent a warming agent over a 20-year span—the length of time in which humanity will be scrambling to get climate change under control—and scientists identify methane controls as one of the quickest, best options for driving down emissions. But in a report last week that focused primarily on CO2 emissions, the International Energy Agency reported that higher fossil gas prices were driving utilities in the United States and parts of Europe to switch back to coal, even though renewable energy was still growing faster as a source of electricity.

GEM concludes that its estimates are significantly higher than calculations by the IEA and the U.S. Environmental Protection Agency, Inside Climate reports. “The numbers just aren’t adding up,” said Driskell Tate. “It’s an area that has dodged a lot of scrutiny.”

While some past reports have come up with even higher numbers for coal mine methane, Inside Climate says GEM’s latest effort is the first to measure emissions from individual mines. “One of the biggest contributions of this report is the level of detail and information they provide about individual coal mines across the globe,” Scot Miller, an environmental health and engineering professor at Johns Hopkins University, told ICN. “If we want to mitigate these emissions, we need to know more than country level emissions. We need to know where these mines are and how much methane is coming out of each mine so that we can develop effective mitigation strategies.”

Those strategies will have to navigate the reality that many developing countries are still heavily dependent on coal. “What we often forget about, in many other countries outside of the United States, coal is still the primary source of electricity, especially in countries like China and India,” Miller said. “Beyond what we do in the United States or Europe to mitigate greenhouse gas emissions, we really can’t forget about emissions problems like tackling methane from coal mining in other countries.”