The U.S. has officially left the Paris Agreement. What happens next?

ON WEDNESDAY, NOVEMBER 4, the United States officially withdraws from the Paris Agreement, the landmark international accord to keep climate change in check and limit future greenhouse gas emissions. The exit occurs regardless of the outcome of Tuesday’s vote, but the winner of the presidential election will decide whether to stay out or to rejoin the landmark climate deal.

The U.S. is now the only major country in the world not committed to the accord, which aims to keep global temperatures from rising more than 3.6 degrees Fahrenheit (2 degrees...