There was no way of knowing on Aug. 8, 1975, just how many readers turned to the new paper in the journal Science by geochemist Wallace Broecker, of Columbia University’s Lamont-Doherty Earth Observatory. It was hardly possible to track clicks or likes nearly half a century ago, so Broecker simply had to hope his message got through. It was a pressing one, conveyed directly by its headline: “Climatic Change: Are We on the Brink of a Pronounced Global Warming?”

The headline marked the first time the term “global warming” is known to have appeared in print, according to NASA. Though Broecker, who died in 2019 after devoting decades to studying and writing about climate change, might have hoped for more from his ground-breaking article, there was barely a whisper f…