Across the World, Diplomats Gird for a Trump Assault on Climate Action

Climate negotiators from Europe, Latin America and some island nations are bracing for the potential return to the world stage of Donald J. Trump, who withdrew the United States from the fight against global warming during his first term.

Nations will press forward without the United States if they must, according to climate negotiators who gathered in New York last week during the United Nations General Assembly. But the first Trump presidency was a setback in the climate fight, and a repeat would slow things down at a critical point when scientists say efforts need to speed up.

“I don’t want this to happen, of course,” said Laurence Tubiana, who served as France’s climate ambassador during the creation of the 2015 Paris agreement, referring to a potential Trump victory. “But I think there will be a sentiment that we have to double down on the Paris agreement framework. I think everybody’s preparing for that.”

The night before Donald J. Trump won the presidency in 2016, an adviser to developing nations in global climate negotiations declared, “No one believes Trump can win, so no real Plan B here!”

After he beat Hillary Clinton to win the White House, Mr. Trump kept the world guessing for months about whether the United States would remain a global partner on climate change. Many leaders reserved early judgment, hopeful that people like Mr. Trump’s daughter, Ivanka, would convince him to stay in. They didn’t.

Mr. Trump, who has dismissed global warming as a “hoax,” made the United States the first and only country to withdraw from the 2015 Paris agreement that calls on countries to cut the pollution from oil, gas and coal that is dangerously heating the planet. The Trump administration also worked with major oil producers