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America is officially the world’s climate pariah.

Every single country in the world has now agreed to work together to fight the greatest challenge of our time—except the United States. On Tuesday, Syria announced that it would join the Paris climate agreement, following Nicaragua’s decision a few weeks ago to do the same. Nicaragua originally abstained because it believed the accord wasn’t strong enough; Syria didn’t join because it was in the middle of a civil war.

America, which joined the Paris agreement under President Barack Obama, now wants to leave the accord under President Donald Trump, the only global leader who explicitly rejects the science of human-caused global warming. As Reuters reported on Tuesday, Trump is also one of the only leaders who isn’t invited to an international climate change summit later this year in France, where nations will discuss implementation of the 2015 deal.

The United States is responsible for spewing more cumulative greenhouse gas emissions into the atmosphere than any other country. Meanwhile, the developing countries that have done the least to cause climate change stand to suffer the worst from increased drought, food and water shortages, and more extreme weather. Given America’s culpability for this global catastrophe—not to mention our vast resources and technological prowess—we should take a leadership role in solving it. Instead, under Trump, we’re absolving ourselves of all responsibility, and our allies want nothing to do with us.