Climate-change chance

The Associated Press reports that, at a U.N. climate conference in Bonn, Germany last week, Syrian representatives said their country will join the Paris climate agreement. That means every country on the planet has embraced the pact.

Except one. The United States, a signatory, recently declared that it will repudiate the agreement. Once a world leader helping to corral other nations to solve common problems, the United States has become a drag on the global response to the largest environmental threat of this century.

President Donald Trump has played down the importance of climate change. Last year he told the Post that the nation faces much graver threats. He is wrong. Even if scientists’ warnings turn out to have been too dire, climate change still poses massive risks to human society.

Trump’s objections are mostly fiction. It does not demand that the United States sacrifice while others do little. The deal merely asks nations to submit voluntary emissions plans. If the commitment that President Barack Obama submitted in Paris is not to Trump’s liking, he could replace it. Meantime, staying in the treaty would make other nations more likely to follow through on their pledges and would build international expectations that all nations will act together, which is the only way climate change will ever be effectively addressed.