Large energy companies including Exxon, Shell, and BP have signed onto a pledge to reduce emissions of methane from natural gas production, part of an effort by the industry to show it is committed to combating climate change even as the Trump administration rolls back regulations forcing them to.

“Providing access to energy, while addressing global climate change, is one of the greatest challenges of the 21st century,” the companies said in the “guiding principles” to their pledge, which they announced Wednesday. “Natural gas plays a major role in meeting global energy demand today. Since natural gas consists mainly of methane, a potent greenhouse gas, its part in the transition to a low-carbon future will be influenced by the extent to which the oil and gas industry reduces its methane emissions.”

The companies didn't make any specific emissions reductions targets, but they promise to “continually reduce methane emissions; advance strong performance across gas value chains; improve accuracy of methane emissions data; advocate sound policies and regulations on methane emissions; and increase transparency.”

Energy companies have promoted natural gas as an important component of addressing climate change because it produces fewer greenhouse gas emissions than coal. They also view natural gas as increasingly important to the stability of the power grid as renewables increase their share, since wind and solar require the sun to be shining and wind to be blowing.

But methane, the main component in natural gas, is more potent than carbon dioxide, although methane emissions are relatively short-lived. Many scientists blame emissions from burning fossil fuels for driving manmade climate change.

The companies developed their pledge in collaboration with the International Energy Agency, the United Nations and other international organizations focused on energy and climate change, according to the Wall Street Journal.

Exxon Mobil’s decision to join the group makes Chevron the only major U.S. oil company that has not joined the pledge.

Exxon has become more involved with addressing climate change after pressure from investors and legal challenges. Exxon CEO Darren Woods urged President Trump not to withdraw from the Paris climate accord.

The American Petroleum Institute, the main trade group representing the oil and natural gas industry, said it was not involved with organizing the pledge.

But the group touted the industry's efforts at reducing methane emissions in a statement to the Washington Examiner.

“The oil and natural gas industry has a strong and proven commitment to safety and environmental performance,” said API Upstream Director Erik Milito. “We have taken strong, voluntary actions to reduce all emissions, including methane which has declined by 16.3 percent in spite of dramatic increases in the production of oil and natural gas, which has increased 51 percent since 1990.”

The pledge represents another example of major energy companies taking a more aggressive posture toward climate change than the Trump administration.

The vow by the energy companies to “advocate sound policies and regulations on methane” is especially noteworthy because the Trump administration is trying to repeal Obama-era methane regulations.

EPA Administrator Scott Pruitt imposed a two-year delay on the implementation of a regulation to limit methane emissions from new oil and natural gas wells. But in July, a federal appeals court blocked the EPA from eliminating the methane rule.

The Republican-controlled Senate, meanwhile, failed in May to pass a measure repealing an Interior Department methane rule affecting existing wells on federal lands.

A federal court in California ruled last month that the Interior Department could not suspend its methane rule.