The world has known about the harmful impact of excessive levels of carbon dioxide for well over a century now. American scientist Eunice Foote had warned about the warming and the basic science behind it more than 150 years ago. In her research paper in 1856, she had theorised that increasing the level of carbon dioxide in the atmosphere would lead to an increase in temperatures.

Global warming is caused due to the 'greenhouse effect.' Certain gasses like methane and carbon dioxide rise to the top of the atmosphere and trap the heat emanating from Earth.

Climate change and the science behind it is often a contentious political issue. While many continue to disregard the effects of global warming caused due by greenhouse gasses like carbon dioxide, their warming effect was first found nearly 170 years ago.

Eunice Foote was the first scientist to record and describe the ability of carbon dioxide to retain heat. It is this ability of carbon dioxide and other greenhouse gases, that has led to an increase in global temperatures. Foote, an inventor and women’s rights activist in the pre-Civil War US, theorised in her paper that increasing the proportion of carbon dioxide would lead to an increase in the average temperature of the atmosphere.

In her paper, ‘Circumstances Affecting the Heat of the Sun's Rays,’ Foote wrote about her findings after doing a simple experiment using glass cylinders with thermometers inside to record the effect of carbon dioxide. In one of the glass cylinders, she pumped in air and in the other she pumped in carbon dioxide. Setting the spheres underneath the sun, she recorded the increase in temperature of both cylinders. She found that the cylinder with carbon dioxide was much hotter than the one full of air. It was based on this, and other experiments, that Foote in 1856 posited that increasing the amount of carbon dioxide in the atmosphere would cause the temperature of the atmosphere to also increase.

She wrote in her paper, “The receiver containing this gas became itself much heated -- very sensibly more so than the other -- and on being removed , it was many times as long in cooling.”

For many, the concept of an odourless, tasteless, and transparent gas having such a damning effect was unthinkable.

While Foote’s experiment did not capture the exact mechanisms of global warming due to the greenhouse effect, it still highlighted the basic idea of how large amounts of carbon dioxide in the atmosphere would lead to increased temperatures.

Foote was the first scientist to publish such observations but she wasn’t alone. A few years later, scientist John Tyndall also noted similar observations in his experiments. After a few decades, in 1896, Svante Arrhenius, a Swedish scientist and Nobel laureate, calculated that “the temperature in the Arctic regions would rise 8 or 9 degrees Celsius if carbon dioxide increased to 2.5 or three times.”

Foote, Tyndall, Arrhenius and others have shown that science has seen and noticed the effect of climate change for well over a century.

Years later, researchers had accurately predicted rising global temperatures. They figured out the role of burning fossil fuels in global warming more than 60 years ago. Scientists spoke about the effects of “weird weather” being felt in the 1960s, but they were dismissed as prophets of doom for linking fossil fuels with climate change.

But unlike the others, Foote was relegated to being a footnote in history. The science journal Nature finally published a letter on the occasion of Foote’s 200th birth anniversary.

"It is a reminder of the struggle that women have gone through to emerge in science and society. Her story is also a reminder that basic elements of climate science, like the warming potential of carbon dioxide, were already being demonstrated over 150 years ago," wrote Annarita Mariotti of NOAA’s Climate Program Office.

(Edited by : Shoma Bhattacharjee)

First Published:Jul 27, 2021 7:39 PM IST