Just two countries refused to partake in the Paris Agreement, the historic climate deal to cut greenhouse gas emissions that was signed by nearly every nation. One of them, Syria, is in ruins after six years of ongoing civil war. The other, Nicaragua, boycotted the accord to protest its unambitious initial goals and its failure to legally bind countries to their emissions targets.

The one other holdout, Uzbekistan, finally signed onto the agreement last month.

But now President Donald Trump is poised to withdraw the United States which was largely responsible, under the Obama administration, for orchestrating the deal from the Paris Agreement.

In 2016, Trump campaigned on a promise to cancel the deal, which he said put an unfair burden on the U.S. and gave poorer countries a pass. The U.S., second only to China in its amount of carbon pollution, committed to slashing emissions by 26 to 28 percent below 2005 levels by 2025.

Former President Barack Obama planned to meet that goal largely by reducing pollution from the utility sector, by far the countrys biggest emitter. To do so, he passed a sweeping regulation called the Clean Power Plan, which put limits on emissions from power stations and encouraged the proliferation of zero-emissions energy sources such as solar and wind. Trump has already moved to dismantle that policy.