Eunice Newton Foote was an American scientist, inventor, and signer of the 1848 Seneca Falls Declaration of Sentiments. In 1856 she ran a simple experiment: she placed glass cylinders in the sun, filled some with ordinary air and others with particular gases, and recorded how hot each one became.
The cylinders holding carbon dioxide heated up the most, and took the longest to cool back down. Water vapor behaved the same way. She drew the conclusion that mattered: an atmosphere with more carbon dioxide in it would hold more heat — and, she wrote, that would raise the temperature of the Earth.
Her paper, "Circumstances Affecting the Heat of the Sun's Rays," was read to the American Association for the Advancement of Science on August 23, 1856 by a male colleague, because women were not permitted to present their own work. It was published that same year.
Three years later, the physicist John Tyndall ran a more precise version of the experiment and became the name most textbooks attach to the discovery. Foote's contribution went largely unnoticed for more than a century, and is still a good illustration of whose work gets remembered.
For your classroom
Why it still matters in a classroom: this entry pairs neatly with the Arrhenius entry, above. Together they show that the science behind the greenhouse effect was worked out by more than one person, over more than half a century — and that the credit did not fall evenly.