President-elect Joe Biden plans to push for the most progressive climate policy the U.S. has ever had, aligning the world’s second-largest carbon emitter with a growing group of nations aggressively tackling global warming. Biden has promised to rejoin the landmark Paris climate agreement on his first day in office, reversing the withdrawal orchestrated by President Donald Trump. He’s also called for the U.S. to have net-zero emissions by 2050, which would make it the last Group of Seven nation to set such a target.

The coming shift from the U.S. will cap a pivotal year for global climate policy that has already seen the European Union, China and others deepen their commitments to fighting climate change. Biden has called for the U.S. to have an emissions-free electric grid in 15 years, one of the most ambitious targets in the world. But his $2 trillion climate agenda will likely face opposition if Republicans retain control of the Senate, forcing him to rely on executive action.

This turnabout sets the stage for an accelerated global effort to combat climate change at a time when record-breaking heat, wildfires and hurricanes are battering communities from Louisiana to the Philippines. It’s also a dramatic reversal from Trump, who ended direct caps on methane emissions, relaxed national fuel-efficiency standards, scrapped the government’s long-range temperature forecasts and discouraged administration staff from publicly acknowledging climate change.

“It strikes me as going from hell to heaven,” said Robert Stavins, a Harvard University professor who’s advised both Republican and Democratic presidents on environmental policies. “It will be shocking to look at the White House and not be embarrassed.”