In 1859, Irish physicist John Tyndall published an article describing how carbon-dioxide and other gases absorb sunlight and release infrared (or thermal) radiation. He speculated that human emission of such gases could change the composition and thermal properties of Earth’s atmosphere, trapping heat on its surface. For over 150 years, this was considered the first scientific study linking greenhouse gases to climate change.
However, in 2016 climate scientist Katharine Hayhoe discovered in the digitized archive of The American Journal of Science and Arts an article written by Eunice Newton Foote, an amateur naturalist from Connecticut.
Born Eunice Newton on July 17, 1819 (Google Doodle celebrating today her 204th birthday) in Goshen, she later became interested, together with her husband Elisha Foote, in physics. She published just two scientific papers in 1856 and 1857, but the first paper is noteworthy as it predates by three years Tyndall’s conclusions.
The article describes an experiment with glass tubes containing air samples with different densities and varying water vapor and carbon gas levels, and a mercury thermometer to record temperature changes. Foote recognizes the role of air density in explaining the decrease of temperature at higher elevations, like experienced on a mountain’s summit where air density is lower. Water vapor actually had the opposite effect, causing the air in the glass tube to warm quicker as aqueous vapor was added to the mix. She observed a similar, maybe even stronger effect when adding carbon gas. Filled with air containing high levels of carbonic acid gas (or carbon-dioxide) and exposed to “the Heat of the Sun’s Ray,” one tube “became itself much heated – very sensibly more so than the other” filled with ordinary air.
Based on her observations, she correctly concluded that varying concentration of gases like water vapor and carbon-dioxide in Earth’s atmosphere could explain changes in Earth’s temperature.
“An atmosphere of that gas would give to our earth a high temperature; and if as some suppose, at one period of its history the air had mixed with it a larger proportion than at present, an increased temperature from its own action as well as from increased weight must have necessarily resulted.”
After Foote published her findings, she produced her second study on atmospheric static electricity. These were the first two physics studies published by a woman in the U.S.
Eunice Newton Foote is credited in an 1856 issue of Scientific American describing women’s contributions to contemporary science. Unfortunately, she was quickly forgotten. Tyndall doesn’t mention her study in his work, and for a very long time her original article was believed to be lost.
Today, scientists all over the world are advancing climate science thanks to the foundation that Foote laid.
Interested in reading more? Try:
“Meet the woman who first identified the greenhouse effect” by Megan Darby.