What Trump’s Climate Legacy Could Look Like

Donald J. Trump has said he plans to reverse major domestic climate policies and withdraw from the Paris climate agreement reached last year. What his administration does could redraw the planet’s map.

These maps show areas in 2100 that could be permanently submerged or flooded during the highest of tides, under three scenarios of sea level rise:

Until recently, scientists predicted that the global sea level could rise almost three feet by the end of this century if greenhouse gas emissions continue unabated. New research suggests faster-than-expected Antarctic melting under this scenario, threatening a rise of nearly six feet — and many feet more after 2100.

But making deep cuts in global emissions could still keep sea level rise below two feet in this century. This is the difference between a difficult but manageable problem and worldwide catastrophe, affecting land where hundreds of millions live today. In the United States, the greatest threat is to South Florida, home to Mr. Trump’s Mar-a-Lago estate.

If Mr. Trump bucks expectations and fights climate change, he might advance his economic and security agenda. American leadership in electrifying the world’s vehicle fleet could revitalize the Midwest manufacturing economy and dry up oil money for Middle East terrorist groups. Investment in American wind and solar power would mean jobs that won’t leave home, and lead toward permanent energy independence.

Mr. Trump clearly wants his legacy to be great. Generations hence may remember him as the man who shrunk America and every other coastal nation — or who shocked the world, again, and helped to save it.