She was the first scientist to confirm that certain gases warm when exposed to sunlight, and that therefore rising carbon dioxide (CO2) levels could increase atmospheric temperature and affect climate, a phenomenon now referred to as the greenhouse effect.

Born in Connecticut, Foote was raised in New York at the center of social and political movements of her day, such as the abolition of slavery, anti-alcohol activism, and women's rights.

In the twenty-first century, new interest in Foote arose when it was realized that her work predated discoveries made by John Tyndall, who had been recognized by scientists as the first person to experimentally show the mechanism of the greenhouse effect involving infrared radiation.

Detailed examination of her work by modern scientists has confirmed that three years before Tyndall published his paper in 1859, Foote discovered that water vapor and CO2 absorb heat from sunlight.

In 2022, the American Geophysical Union instituted The Eunice Newton Foote Medal for Earth-Life Science in her honor to recognize outstanding scientific research.

[4][5][8] Her father died in 1835 and the fifth child, a daughter named Amanda, took it upon herself to rid the properties of debt and become sole owner to keep the family farm from being sold.

Students of the seminary were encouraged to attend science courses at the adjacent Rensselaer School, which was led by Amos Eaton, the senior professor and a proponent of women's education.

[18][22][23] During Newton's attendance, the assistant principal of the seminary was Willard's sister Almira Hart Lincoln Phelps, who prepared the school's curricula and wrote textbooks for the students.

[31][38] On her 1862 passport application, the officials described Foote as being just under 5 ft 2 in (1.57 m) tall, with blue-gray eyes, a "rather large" mouth, with an oval face, a sallow complexion, and dark brown hair.

[61][63] She also placed the containers in the shade for comparison and tested the temperature results by dehydrating one cylinder and adding water to the other, to measure the effect of dry versus moist air.

[65] Foote described her findings in a paper, "Circumstances Affecting the Heat of the Sun's Rays", that she submitted for the tenth annual AAAS meeting, held on August 23, 1856, in Albany, New York.

[29] Yet, he discounted her findings in the New-York Daily Tribune article about the presentation, saying "although the experiments were interesting and valuable, there were [many] [difficulties] encompassing [any] attempt to interpret their significance".

[59][61] Summaries of Foote's work were included in the 1857 edition of The Annual of Scientific Discovery,[6][72] the Canadian Journal of Industry, Science and Art (1857),[6][73] the Jahresbericht über die Fortschritte der reinen, pharmaceutischen und technischen Chemie, Physik, Mineralogie und Geologie, 1856 (Annual Report on the Progress of Pure, Pharmaceutical, and Industrial Chemistry, Physics, Mineralogy, and Geology, 1856 (Giessen, 1857), the Edinburgh New Philosophical Journal (1857),[70] the newspaper New-York Daily Tribune, and the magazine Scientific American (1856).

[76] In the late 1770s, Horace Bénédict de Saussure had used a similar apparatus to Foote's and concluded that altitude impacted solar heat in an enclosed cylinder.

[63][78] In 1859, John Tyndall reported his more sophisticated research, using a Leslie cube and a differential spectrometer, showing that several gases both trapped and emitted infrared thermal radiation rather than sunlight.

[77][83] By expanding or compressing air, Foote noted that the moisture content was changed, which in turn affected the amount of static electricity that could be generated.

She was working from a hypothesis that electric charges and fluctuations in atmospheric pressure might explain the Earth's magnetic field and polarity, which was later shown by other scientists not to be the case.

[84] Foote's paper, "On a New Source of Electrical Excitation", was again read by Henry at the annual AAAS conference held in Montreal, on the third day of proceedings, August 14, 1857.

[42] Rachel Brazil, a science writer for Chemistry World, noted in 2020 that Elisha filed a patent in 1842 on a thermostatically controlled cooking stove which had been invented by Eunice.

[17] Biases against crediting women scientists for their work led to a lack of documentation about her contributions and scientific achievements,[97] and Foote fell into obscurity.

[71][100][101] In 1902, Susan B. Anthony made a speech calling on younger feminists to take up the reins from founders of the movement like "Elizabeth Cady Stanton, Lucretia Mott, Eunice Newton Foote, Mary Livermore, and Isabella Beecher Hooker.

[113] Lois Barber Arnold, who taught in the Science Education Department of the Teachers College, Columbia University,[114] described Foote's experiments and participation in the AAAS conferences in detail in 1984, but noted that biographical data on her was lacking.

[121][120] She published an article "John v Eunice — A Fascinating Tale of Early Climate Science, Women's Rights and Accidental Poisoning" on Facebook in 2016.

[125] Roland Jackson, a visiting scholar at the London-based Royal Institution,[126] set out in 2019 to analyze the questions of priority of Foote's work, as had Hayhoe in 2016.

[63][71][120] Because Tyndall had more sophisticated equipment, Hayhoe noted that he was able to make these distinctions and conclusively measure the "heat-trapping properties" of several gases, by differentiating their infrared energy and the ability of molecules to absorb or emit radiation.

[62][119] She recognized that Foote's experiments confirmed that when subjected to sunlight, carbon dioxide became warmer than air "thereby demonstrating what we call the greenhouse effect today".

"[134] Jackson's work in 2019 confirmed that Foote's experiments showing that water vapor and CO2 absorb heat occurred three years before Tyndall made a similar claim.

[70] Jackson also notes that many European scientists, including George Stokes and William Thomson, were unaware of Foote's work since her name is not mentioned in any of the "correspondence, journals, or published papers of the critical physicists" of her era.

[18] Jeff Hecht, a science and technology writer, acknowledged that the reasons why Tyndall did not credit Foote remain unknown but that he "…might have ignored a discovery claimed by a woman".

[4] That year, Cornell University Press released a textbook Communicating Climate Change: A Guide for Educators confirming that Foote's work preceded that of Tyndall.