A short paper titled “Circumstances affecting the Heat of Sun’s rays” appeared in the 1856 edition of the American Journal of Science and Arts. It was only a page and a half long, and had a brief and crisp description of three experiments.
Effect of density
The first one studied how the warming of air by the Sun’s rays was affected by its density. Two identical containers, one with rarefied air and the other with condensed air, were kept side by side in the sun.
The author, Eunice Newton Foote, found that the temperature of the condensed air rose significantly more (to 110 oF) than that of the rarefied air (88 oF).
Effect of humidity
In the second experiment, Foote used one container with humid air and another with dry air and saw that the former became more warm.
Warming of different gases
The final experiment described in the paper compared the warming of different gases as compared to air. Foote noted that a jar filled with carbon dioxide (or “carbonic acid gas” as it was known then) got heated much more than one with common air.
She postulated that a greater proportion of carbon dioxide in the atmosphere could cause an increase in temperature, effectively predicting global warming as we know it today.
Unknown until 2010, Celebrated in 2018
Foote’s work was not widely recognised until as recently as 2010, when Ray Sorenson, a retired geologist stumbled upon her paper. Sorenson realised that Foote’s paper preceded by three years the work of John Tyndall, who had been previously credited with recognising the greenhouse effect of carbon dioxide.
In 2018, 162 years after her landmark paper, Eunice Newton Foote’s work was commemorated in a symposium at the University of California Santa Barbara. A charming short film titled Eunice was also released in the same year to honour the forgotten scientist.
- Wikipedia article on Eunice Newton Foote. https://en.wikipedia.org/wiki/Eunice_Newton_Foote
- New York Times. Overlooked No More: Eunice Foote, Climate Scientist Lost to History.
- American Journal of Science and Arts 1856.