Oil and gas companies for the first time will face fines for emitting methane, a potent greenhouse gas that leaks from wells, pipelines and storage facilities, the Biden administration announced on Tuesday.

John Podesta, President Biden’s top climate diplomat, discussed the congressionally mandated measure at the United Nations climate summit in Baku, the capital of Azerbaijan. Administration officials are trying to reassure other countries that U.S. climate action will continue even after the impending return of Donald J. Trump to the White House.

Methane is considered a “superpollutant” because while it dissipates more quickly than carbon dioxide, it traps about 80 times more heat in the atmosphere in the short term. Methane emissions from the United States have risen sharply, the result of a booming fossil fuel industry that is producing and exporting oil and gas at record levels.

The Biden administration has made slashing methane a major part of its climate strategy and has encouraged other nations to do the same. When it passed the landmark climate law, the 2022 Inflation Reduction Act, Congress required that large oil and gas companies pay a fee for methane pollution to encourage them to stop emitting. The law spells out the amounts to be charged.

“Slashing these superpollutants is the fastest and often, I would add, the cheapest way to slow down warming in the coming decades,” Mr. Podesta said at a joint event with officials from China and Azerbaijan, where those countries detailed their efforts to curb potent greenhouse gases like methane and nitrous oxide.

Many in the oil industry strongly oppose the methane fee. Several billionaire donors to Mr. Trump’s presidential campaign who run oil companies have made it clear that they want him to scrap it. The American Exploration and Production Council and the American Petroleum Institute, two of the biggest trade groups representing oil and gas producers, also want the fee erased.