ֹ Magazine Spring/Summer 2021 By Candace Goforth DeSantis, BS ’94, and Jim Maxwell, BS ’00, MS ’11
By now, it is well understood that the role of women in science has gone largely uncredited throughout history. In recent years, a movement has grown to correct the record and bring attention to the overlooked contributions of women scientists. One of those women is Eunice Newton Foote, whose discovery 165 years ago paved the way for our modern understanding of Earth’s natural greenhouse effect, which is fundamental to the study of climate change.
Joseph D. Ortiz, PhD, co-authored a paper assessing the experiments described in Eunice Foote’s 1856 paper. Photo by Bob Christy, BS ‘95
Joseph D. Ortiz, PhD, professor and assistant chair in the Department of Geology at ֹ, first learned about Eunice Foote a few years ago from Elizabeth Griffith, PhD, a colleague who is now a faculty member at The Ohio State University. When Ortiz found and read a paper Foote had written in 1856, “I was floored by the elegance of her experiments,” he says. “She took what was known from geology, infused it with physical experimentation and helped to create the modern field of climate science—but without receiving credit.”
In the 1850s, Eunice Foote—an American amateur scientist, inventor and early activist for women’s rights—studied the effect of the sun’s rays on different atmospheric gases. Through a series of experiments using an air pump, thermometers and two glass cylinders, Foote discovered that carbon dioxide (which she called carbonic acid vapor) and water vapor could warm air in an experimental vessel. She found that a closed cylinder filled with carbon dioxide and exposed to sunlight trapped more heat and stayed hot longer than one left in the shade.
From that observation, she hypothesized that carbon dioxide and water could warm the atmosphere and influence climate on Earth during modern and ancient geologic times.
Geologists at the time were discovering that the world’s climate and vegetation had once been dramatically different. By studying coal deposits that had formed in swampy seas, they concluded that the atmosphere had once held much higher levels of carbon dioxide. But the geologists of the day felt that carbon dioxide only served as “food for plants,” Ortiz says. No one had yet considered that it may have an influence on climate.
Although Foote’s hypothesis that carbon dioxide in the ancient atmosphere would have made Earth much warmer was correct, notes Ortiz, her experimental design wasn’t sophisticated enough to reveal how carbon dioxide or water vapor led to warming. “Even so,” he says, “her work was a tremendous leap in thinking that some view as the birth of climate science.”
“Her work was a tremendous leap in thinking that some view as the birth of climate science.”
—Joseph D. Ortiz, PhD
Foote collaborated with her husband, Elisha Foote, a judge and inventor, but they published separately. He studied how the sun’s rays could be amplified, perhaps to build a hot water heater or oven, and presented his paper at the 10th annual meeting of the American Association for the Advancement of Science on Aug. 23, 1856, in Albany, New York.
Eunice Foote also submitted her paper on the CO2 discovery to the association, but hers was presented, on her behalf, by physicist Joseph Henry, director of the Smithsonian Institution, at the same meeting. It was published as in the American Journal of Science and Arts in November 1856 immediately following Elisha Foote’s paper, “On the heat in the Sun’s rays.”
“Circumstances affecting the heat of the Sun’s rays,” by Eunice Foote, was published in the American Journal of Science and Arts in November 1856.
Despite this, while her husband’s paper was republished in a prominent European journal, her paper was overlooked, Ortiz says. A summary of her work was published in the 1857 volume of The Annual of Scientific Discovery by David A. Wells. Five years later, Wells mentioned it without attribution i