THE history of today’s climate change debate may have begun on Feb. 7, 1861. That day, an Irish physicist named John Tyndall, a professor of natural philosophy, delivered the annual Bakerian Lecture to the Royal Society in London.

Dark-eyed and quick-witted, Tyndall was a dazzling figure who drew huge audiences to his public lectures on lively new subjects like glaciation, radiation and sound. “I never saw so large an attendance in the rooms of the Society,” he wrote in his journal that night. Even Alfred Tennyson, the poet laureate, sat amid the “many remarkable men present.”

Tyndall had news. He revealed that for two years he had been studying the heat-absorbing properties of gases. He realized that for the earth’s atmosphere to maintain its steady temperature, certain gases must be capable of trapping radiant heat. This inquiry, he said, was “perfectly unbroken ground.”

His experiments had shown that gases like oxygen, hydrogen and nitrogen retained very little heat. But others, particularly carbon dioxide, absorbed surprising amounts of radiation — “nearly 100 times as much as oxygen,” he said.

For the sharp minds in the hall, the implication of Tyndall’s discovery was clear. The higher the concentrations of absorptive gases in the atmosphere, the higher atmospheric temperatures would be. Thus was laid the theoretical foundation for climate science — though few could have envisioned that, more than 150 years later, Tyndall’s discovery would be one of the great political debates of the day....