When Donald Trump pulled out of the Paris climate accord, he may have achieved something few presidents ever manage: changing the way the world works.

Actually, he may have done it twice.

The first way is both deceptively simple and monumentally damaging. By slowing the global momentum toward renewable energy, Trump has guaranteed that the Earth will become a hotter place to live—which means less ice and coral, more drought and flood. The last presidential decision to show up on the geologic record was the atom bomb: Testing the giant weapons has left a layer of cesium and plutonium on the planet’s crust that will last for millions of years. Assuming Trump refrains from dropping a nuke himself, it’s his climate policy that will leave a permanent mark.

It was almost as if California were a nation-state—one that has talked about launching its own satellites to monitor melting polar ice.

But the Paris decision may also reshape the world for the better, or at least the very different. Consider: A few days after Trump’s Rose Garden reveal, California Governor Jerry Brown was in China, conducting what looked a lot like an official state visit. He posed with pandas, attended banquets—and sat down for a one-on-one meeting with President Xi Jinping, which produced a series of agreements on climate cooperation between China and California. (Trump’s secretary of energy, Rick Perry, was in Beijing the same week: no pandas, no sit-down with Xi.) It was almost as if California were another country. Call it a nation-state—a nation-state that has talked about launching its own satellites to monitor melting polar ice. A nation-state that has joined New York and a dozen others in a climate alliance to announce they will meet the targets set in the Paris accord on their own. A nation-state that already holds joint auctions with Quebec in its carbon cap-and-trade program. A nation-state that is convening hundreds of other “subnational actors” from around the world next year to pledge to keep the rise in global temperature below 2 degrees Celsius.

I remember, as a college newspaper reporter, sitting next to Jerry Brown on his campaign bus in 1980, a few days before the New Hampshire primary. He spent 45 minutes explaining to me that it wouldn’t be long before we had wristwatch telephones à la Dick Tracy. That kind of time allocation may explain why Brown got just under 10 percent of the vote in New Hampshire, forcing him to drop out of the race. Still, calling the Apple Watch more than three decades out is a pretty good trick. It’s worth asking whether he’s ahead of the curve once more.