Exxon Mobil, Chevron and Occidental Petroleum are joining a group of international oil and gas giants in an initiative aimed at curbing carbon emissions in the sector, they said in a statement on Thursday.

The move marks a U-turn for Exxon Mobil and Chevron, the top two U.S. oil and gas producers which had resisted joining the Oil and Gas Climate Initiative (OGCI) after its launch in 2016.

The OGCI currently comprises 10 firms including BP, Royal Dutch Shell, France’s Total as well as national oil companies of China, Mexico, Brazil and Saudi Arabia. Together with the new U.S. members, the group will account for around 30 percent of global oil and gas production.

The announcement comes ahead of the Climate Week in New York next week, a global gathering of world and company leaders around climate change.

“We are pleased to be joining OGCI to work constructively on addressing the risks of climate change,” Chevron Chief Executive Officer Michael Wirth said in the statement.

The OGCI last year created a $1 billion fund to develop technologies to reduce emissions of greenhouse gases in the sector as the world aims to shift towards a low-carbon economy.

Exxon in recent years came under fire from investors and faced lawsuits over its climate policies and disclosures.

Exxon produced a report in February outlining how global oil demand could drop sharply by 2040 as a result of a growing number of electric vehicles, but critics said the report fell short on areas such as how climate policies could affect company finances.

“It will take the collective efforts of many in the energy industry and society to develop scalable, affordable solutions that will be needed to address the risks of climate change,” Exxon CEO Darren Woods said in the statement.

“Our mission is to supply energy for modern life and improve living standards around the world while minimizing impacts on the environment. This dual challenge is one of the most important issues facing society and our company.”

The news of the U.S. firms’ joining was first reported by Axios.