The MIT professor was unequivocal.

“If we had to stop producing CO₂, no coal, oil, or gas could be burned,” Carroll Wilson declared. The world would have to adopt nuclear energy en masse and perhaps even turn to “electric motor vehicles.”

It was June 9, 1971. Wilson, a management professor, wasn’t speaking at an environmental rally or a scientific meeting. He was talking to a room full of engineers and businessmen who had gathered in Cleveland, Ohio, for the electricity industry’s annual conference.

His speech was as up-to-date a discussion of climate science as you could find in the early 1970s. Although he said that global warming wasn’t yet a scientific certainty—which was true in those days—he was clear that it needed to be taken seriously. And the conference’s organizer, the Edison Electric Institute, seemed keen to get the best climate research in front of its members, even if it had radical implications for their business.

Yet scarcely two decades later, virtually the entire electric-utility industry—including the Edison Electric Institute, its flagship lobbying group, and the Electric Power Research Institute, its leading R&D alliance—united against any effort to understand or stop climate change. In 1992, an EEI article said that global warming would not portend disaster, but bring “cooler days, warmer nights, and better vegetables.”

Why has it taken so long for the United States to treat climate change seriously, much less adopt serious efforts to stop it? Over the past few years, the public has come to understand at least one cause: A handful of oil companies understood the reality of climate change years before the general public, but waged an expensive and secretive campaign through the 1990s and 2000s to muddy the science and play down the dangers.

But oil companies did not act alone. “Utilities were also in the room,” Emily Williams, a researcher at UC Santa Barbara and a co-author of a new study about the electricity industry’s role in spreading climate denial, told me. Years after scientists had reached a consensus that global warming was real, dangerous, and caused by fossil fuels, utilities sold climate half-truths and untruths to policy makers and the public.