Every U.S. presidential election is consequential, but American voters face an unusually weighty decision in 2024. The outcome will have implications for U.S. foreign policy, social policy and the integrity of the political system itself. But none of its consequences will be more profound or far-reaching than on global efforts to combat climate change.

As president, Donald Trump pulled the United States out of the Paris climate agreement, while the U.S. under President Joe Biden rejoined it. Trump has vowed to expand oil and gas production and his campaign has vowed that he will again withdraw the U.S. from the Paris accord if he wins a second term.

By contrast, Vice President Kamala Harris, the Democratic nominee, supported the Green New Deal, an ambitious congressional plan for tackling climate change, while serving in the Senate in 2019. As California’s attorney general, she investigated the oil industry, securing a settlement from a subsidiary of British Petroleum for underground gas tank ruptures, as well as indictments against a Texas-based pipeline operator for an environmentally damaging oil leak.