Friday 20 December 2019

Global warming: warnings from Victorian times

Thanks to JSTOR, I now know that the great Joseph Fourier, mathematician and physicist, had the intuition back in the early nineteenth century that the earth's mantle of various gases was responsible for keeping the planet warmer than his calculations showed that it should be. He also surmised that "over a long period of time, the amount of heat held in by the atmosphere could change — altered by both the Earth’s natural evolution and human activity."

Fourier did not pin down the exact mechanism or which gas was most responsible for what we now name the greenhouse effect. This identification was first made by an American amateur scientist, Eunice Newton Foote. "She took several glass cylinders, put a thermometer in the bottom, and then filled them with gas combinations ranging from very thin air to thicker air, humid air, and air with 'carbonic acid,' or what we now call CO2. Foote placed the cylinders in the sun to heat up, then in the shade to cool down. When she observed how the temperatures changed, she found that the cylinder with CO2 and water vapor became hotter than regular air, and retained its heat longer in the shade. In other words, wet air and CO2 were heat-trapping gases. When she wrote up her experiment for an 1856 issue of The American Journal of Science, Foote made an eerily prophetic observation: What happened inside the CO2 jar could also happen to our planet. 'An atmosphere of that gas,' she noted, 'would give to our earth a high temperature.'"

Three years later, John Tyndall, after whom the Tyndall Centre for Climate Research is named, followed.

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