Half of the world’s energy sector methane pollution is emitted by just 30 fossil fuel companies, according to Global Energy Monitor Analysis released Thursday. A potent, but short-lived greenhouse gas, methane traps more than 80 times more heat in the atmosphere than CO2 over a 20-year period, and rapidly and dramatically slashing methane pollution is the most feasible way to limit global warming to 1.5°C (2.7°F).

State owned companies ranked worst, with National Iranian Oil Co., Gazprom PJSC and China Energy Investment Corp. making up the top three. The GEM report is consistent with other recent reports on the concentrated nature of methane pollution in the oil and gas sector, and highlights how cutting methane pollution is an efficient way to limit climate change, especially in the short term.

“There are vast differences between countries in how much methane they emit for each unit of oil and gas they extract. This shows that these emissions are avoidable,” Mason Inman, one of the authors of the report, said. “About half of oil and gas methane emissions could be eliminated at no net cost to the companies, since they would capture more natural gas and be able to sell it.” (Bloomberg $)