A win for Donald Trump in the November presidential election could increase the United States planet-heating pollution by so much that the emissions would negate the last five years of global progress on deploying clean energy twice over.

Thats the conclusion of a new analysis from Carbon Brief .

The climate science journals new report found that the Republican candidates plans to reverse the Biden administrations energy policies would add an extra 4 billion metric tons of carbon dioxide equivalent to the atmosphere. The total is roughly equal to the combined annual emissions of the European Union and Japan or the combined yearly sum of the worlds 140 lowest-emitting countries.

Trump, now all but certain to clinch the GOPs nomination for president, is leading in many polls against President Joe Biden, whose signature legislative achievement, the Inflation Reduction Act of 2022, marks the most significant climate law yet enacted in the U.S.