Eunice Newton Foote was an American scientist and inventor, and a women’s rights campaigner from Seneca Falls, New York.
She was the first scientist known to have experimented on the warming effect of sunlight on different gases and went on to theorize that changing the proportion of carbon dioxide in the atmosphere would change its temperature.
When the industrial revolution began in the late 1700s, it brought with it several technological advancements that humanity had not dared to dream of for thousands of years. But everything has a downside to it, and the Industrial Era was no exception—the cost ranged from unbearable local pollution in the short-term to persistent global warming in the long run.
With the advent of steam engines and large-scale coal burning, a lot more carbon dioxide was being released into the atmosphere compared to pre-industrial times. And while most humans were too busy enjoying the fruits of industrialization to notice that something was seriously wrong, a very tiny subset of researchers speculated on what was coming and even tried to warn humanity.
One of the earliest warnings came 165 years ago, from Eunice Newton Foote. But like many other women of her time, Eunice was largely ignored, and so were her findings.
Eunice Newton Foote, an amateur scientist, and prominent suffragette, for the first time, tested the heat-trapping abilities of different gases. 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.”
Foote’s discovery of the high heat absorption of carbon dioxide gas led her to conclude that “… if the air had mixed with it a higher proportion of carbon dioxide than at present, an increased temperature” would result.
A few years later, in 1861, the well-known Irish scientist John Tyndall also measured the heat absorption of carbon dioxide and was so surprised that something “so transparent to light” could so strongly absorb heat that he “made several hundred experiments with this single substance.”
Tyndall also recognized the possible effects on the climate, saying “every variation” of water vapor or carbon dioxide “must produce a change of climate.” He also noted the contribution other hydrocarbon gases, such as methane, could make to climate change, writing that “an almost inappreciable addition” of gases like methane would have “great effects on climate.”