We often think of climate science as something that started only recently. The truth is that, like almost all fields of science, it started a long time ago. Advancing science is often a slow and tedious process, and climate science is not an exception. From the discovery of carbon dioxide until the most sophisticated climate models, it took a long time to get where we are.

Unfortunately, many scientists who played an important role in this climate journey are not given the credit they deserve. Take, for instance, Eunice Newton Foote.

Foote was born in 1819 in Connecticut, USA. She spent her childhood in New York and later attended classes in the Troy Female Seminary, a higher education institution just for women.  She married Elish Foote in 1841, and the couple was active in the suffragist and abolitionist movements. They participated in the “Women’s Rights Convention” and signed the “Declaration of Sentiments” in 1848.

Eunice was also an inventor and an “amateur” scientist, a brave endeavor in a time when women were scarcely allowed to participate in science. However, one of her discoveries turned out to be instrumental in the field of climate science.

Why do we need jackets in the mountains?

In 1856, Eunice conducted an experiment to explain why low altitude air is warmer than in mountains. Back then, scientists were not sure about it, so she decided to test it. She published her results in the American Journal of Science and Arts.

Foote placed two cylinders under the Sun and later in the shade, each with a thermometer. She made sure the experiment would start with both cylinders with the same temperature. After three minutes, she measured the temperature in both situations. 

She noticed that rarefied air didn’t heat up as much as dense air, which explains the difference between mountaintops and valleys. Later, she compared the influence of moisture with the same apparatus. To make sure the other cylinder was dry enough, she added calcium chloride. The result was a much warmer cylinder with moist air in contrast to the dry one. This was the first step to explain the processes in the atmosphere, water vapor is one of the greenhouse gasses which sustain life on Earth.

But that wasn’t all. Foote went further and studied the effect of carbon dioxide. The gas had a high effect on heating the air. At the time, Eunice didn’t notice it, but with her measurements, the warming effect of water vapor made the temperatures 6% higher, while the carbon dioxide cylinder was 9% higher. 

Surprisingly, Eunice’s concluding paragraphs came with a simple deduction on how the atmosphere would respond to an increase in CO2. She predicted that adding more gas would lead to an increase in the temperature — which is pretty much what we know to be true now. In addition, she talked about the effect of carbon dioxide in the geological past, as scientists were already uncovering evidence that Earth’s climate was different back then.

We now know that during different geologic periods of the Earth, the climate was significantly warmer or colder. In fact, between the Permian and Triassic periods, the CO2 concentration was nearly 5 times higher than today’s, causing a 6ºC (10.8ºF) temperature increase.

Recognition

Eunice Foote’s discovery made it to Scientific American in 1856, where it was presented by Joseph Henry in the Eighth Annual Meeting of the American Association for the Advancement of Science (AAAS). Henry also reported her findings in the New-York daily tribune but stated there were not significant. Her study was mentioned in two European reports, and her name was largely ignored for over 100 years — until it finally received credit for her observations in 2011. 

The credit for the discovery used to be given to John Tyndall, an Irish physicist. He published his findings in 1861 explaining how absorbed radiation (heat) was and which radiation it was – infrared. Tyndall was an “official” scientist, he had a doctorate, had recognition from previous work, everything necessary to be respected. 

But a few things draw the eye regarding Tyndall and Foote.

Dr Tyndall was part of the editorial team of a magazine that reprinted Foote’s work. It is possible he didn’t actually read the paper, or just ignored it because it was an American scientist (a common practice among European scientists back then), and or because of her gender. But it’s possible that he drew some inspiration from it as well — without quoting it.

It should be said that Tyndall’s work was more advanced and precise. He had better resources and he was close to the newest discoveries in physics that could support his hypothesis. But the question of why Foote’s work took so long to be credited is hard to answer without going into misogyny.

Today, whenever a finding is published, even if made with a low-budget apparatus, the scientist responsible for the next advance on the topic needs to cite their colleague. A good example happened to another important discovery involving another female scientist. Edwin Hubble used Henrietta Swan Leavitt’s discovery of the relationship between the brightness and period of cepheid variables. Her idea was part of the method to measure the galaxies’ velocities and distances that later proved the universe is expanding. Hubble said she deserved to share the Nobel Prize with him, unfortunately, she was already dead after the prize announcement.

It’s unfortunate that researchers like Foote don’t receive the recognition they deserve, but it’s encouraging that the scientific community is starting to finally recognize some of these pioneers. There’s plenty of work still left to be done.