The Costs of Leaving the Paris Climate Deal

When the leaders of nearly 200 countries celebrated reaching the landmark Paris Agreement in December 2015 after years of false starts, they thought they had finally addressed the issue in a way that would resist the whims of leaders less inclined to act on climate change.

The deal gave countries—and government officials—the freedom to set their own voluntary targets and to revise them as they saw fit. Failure to meet them would only hurt the country's reputation.