The Senate voted 69-27 on Wednesday to approve a treaty that would limit highly potent greenhouse gases, a step experts say could buy humanity valuable time to stave off the worst repercussions of climate change.

Approval of the treaty, the Kigali Amendment, came as world leaders gathered at U.N. headquarters in New York, where U.N. Secretary-General António Guterres warned this week that rising greenhouse gas emissions placed the world on a path to “global suicide.”

He and other world leaders, including President Joe Biden, noted that the gathering took place as much of Pakistan remained flooded — experts link more frequent and catastrophic extreme weather events to a warming climate — and during a year that has broken temperature records.

The Senate approved the treaty after voting to include an amendment critical of China from Sen. Dan Sullivan, R-Alaska.

Ratification comes as demand for air conditioning worldwide is climbing and six years after world leaders negotiated the treaty in Kigali, the capital of Rwanda, to phase out the use of hydrofluorocarbons, or HFCs. Those chemicals are found in air conditioners, refrigerators, insulation, foam and other household and industrial products.

Industry groups, environmentalists, scientists and a bipartisan group of lawmakers have pushed for years for the Senate to approve the treaty, which the Trump administration never submitted to the chamber despite bipartisan calls to do so.

The Biden administration submitted the treaty for consideration in November, and the Senate Foreign Relations Committee held a hearing on it in April, when the top Democrat and Republican on the panel both voiced support.

“We’ve come together on something that’s extremely important for us, for my generation, but even more important for those who follow us,” Sen. Thomas R. Carper, D-Del., said after the vote.

Bipartisan effort

He and Sen. John Kennedy, R-La., have long pushed for the Senate to take up the treaty.

Former President Donald Trump signed into law a bill both senators backed to phase down the use of HFCs in the U.S., and the EPA last year began following steps to cut HFCs in the U.S. by 85 percent by 2036, a target that would meet the treaty’s requirements.

Business groups including the U.S. Chamber of Commerce, the National Association of Manufacturers and the American Chemistry Council urged senators to vote for the treaty in a letter in June.

“Failure to ratify the Kigali Amendment could limit U.S. manufacturers’ ability to access certain international markets and hinder environmental progress,” the letter said, citing industry projections that approval of the treaty could lead to $12.5 billion in new investment in the U.S. in the next decade.

Kigali is the fifth amendment of another global treaty, the Montreal Protocol, agreed to in 1987. All have been approved by the Senate.

World leaders agreed to the Montreal deal in 1987 to phase out chlorofluorocarbons, or CFCs, because they eroded the ozone layer. The Montreal agreement ushered in substitute chemicals that do not harm the ozone layer. But those chemicals, HFCs, are thousands of times more powerful greenhouse gases than carbon dioxide.

In the decades following Montreal, environmental advocates campaigned for a new treaty to cut HFC use — a step experts say can save half a degree Celsius in warming and buy time to make more emissions cuts.

“The United States is back at the table leading the fight against climate change,” Biden said in a statement after approval. “As more countries join the United States in ratifying this amendment, we can prevent up to half a degree Celsius of warming this century, a significant contribution to fighting climate change and protecting communities from more extreme impacts.”

Earth’s temperature has risen more than 1.2 degrees Celsius since the Industrial Revolution, according to NASA, close to the 1.5-degree tipping point of warming at which climate scientists say climate damage increases exponentially.

Treatment of China

Sullivan and Sens. Mike Lee, R-Utah, and John Barrasso, R-Wyo., criticized the treaty before passage over its definition of China, which has agreed to Kigali, as a “developing” nation, a category that gives countries more time to comply with the treaty obligations.

“It gives China special treatment,” Barrasso said of the treaty. If the U.S. wanted to do more on HFCs, it could rewrite the law Trump signed, Barrasso said. “It’s a façade. China is not a developing country,” Sullivan said.

China, the No. 2 economy in the world and the current greatest emitter of greenhouse gases of any nation, is far from an emerging economy, Sullivan said.

Members voted 96-0 to adopt Sullivan’s amendment. It requires the State Department, before Nov. 6, to propose naming China as an industrialized nation under the U.N. Framework Convention on Climate Change, the main international forum for climate diplomacy.

“Americans should reap the rewards of American innovation,” Kennedy said in a statement. “Today, the Senate defended U.S. innovation and countered the economic rise of China and other bad actors at a time when American workers and consumers need all the commonsense support they can get.”

Louisiana’s other senator, Bill Cassidy, a Republican, also voted for the treaty. The state is a hotbed for chemical manufacturing.

Before the vote closed, Senate Majority Leader Charles E. Schumer, D-N.Y., and Sens. Kirsten Gillibrand, D-N.Y., and Martin Heinrich, D-N.M., were whipping votes in the Senate well, trying to get Republicans to vote for the treaty.

Telling Republicans the treaty was strong on China and good for domestic jobs, Gillibrand seemed to have persuaded Sen. James M. Inhofe, R-Okla., who initially voted for the treaty.

‘Thank you, Jim, thank you,” she said. After consulting with aides, Inhofe changed his vote and voted no.

Schumer appeared to ply a similar tactic with Sen. Tom Cotton, R-Ark., saying the treaty was “anti-China.”

Before casting their votes, several Republicans paused and consulted staff and colleagues about how to vote.

At one point, Sen. Ben Sasse, R-Neb., pulled up a roll call sheet listing how senators voted. After chatting with colleagues, the Nebraskan voted “aye” and gestured to Heinrich, who pumped his fist and gave thumbs-up in response.

One-hundred-thirty-seven nations have ratified Kigali. If the U.S. does not ratify the treaty, it could face economic sanctions and lose out on more than 30,000 new manufacturing jobs, according to industry estimates.

Approval of a treaty requires a two-thirds majority vote of senators present, and contrary to popular belief, the Senate does not ratify treaties. Rather, it consents to ratification, and after passage in the Senate the process shifts to the executive branch, at which point the president decides whether to take the final step to ratify the treaty.

During the treaty approval process, the Senate can apply what are known as reservations, understandings and declarations, or RUDs, on a treaty, which can change or guide the implementation and nature of the treaty.

“If the president ratifies the treaty, the president is considered to have accepted the RUDs,” according to the Congressional Research Service. “If the president finds the RUDs unacceptable, the President can decline to ratify the treaty.”

If ratification proceeds, “the president or an executive branch designee signs and affixes the United States’ seal to an instrument of ratification,” the analysis said.