Rafe Pomerance, an environmentalist who discovered in an obscure 1979 report that burning coal heats the atmosphere, which roused him, Paul Revere-like, to warn the public and politicians about climate change, died on May 21 in Washington, DC. He was 79.

Mr. Pomerance emerged as the central figure in a whole-issue article in The New York Times Magazine in 2018, “Losing Earth” by Nathaniel Rich. The article later expanded into a book and is now in production as a movie.

Earlier cautions about climate change, first noted in 1896 into the 1960s had been largely ignored. Dire warnings about increased carbon in the air predicting melting ice sheets, rising seas, calamitous weather and imperiled species did not catch the awareness of the public, politicians, media or environmental groups, which were focused on smog and toxic waste dumps.

“Shouldn’t I be totally depressed?” he asked in 2019. “Yet, I’m not.” One reason was how many people had come to understand the climate crisis. “When I started, nobody had heard of the problem. Nobody was active,” he said. “We started at zero. Well, look at us now. Everybody in the world knows about climate change. So is that progress? Let’s hope.”