Living Lightly column

An early history of climate change science

By Lauriston Muirhead

Way back in the 1850s American scientist, Eunice Foote, conducted experiments clearly demonstrating the powerful heating effect of CO2.  Her work “Circumstances Affecting the Heat of Sun’s Rays” was published in The American Journal of Science in September 1856.

Foote exposed cylinders of the component gases of the atmosphere to the sun and wrote: “The highest effects of the sun’s rays I have found to be in carbonic acid gas.”  [“Carbonic acid gas” is what we now call carbon dioxide (CO2)]

She then gives a table of results showing the increased heating effect in the cylinder containing CO2 compared to the cylinder containing “common air” and goes on to say:

“The receiver containing the gas became itself much heated – very sensibly more so than the other [containing the “common air”] – and on being removed, it was many times as long in cooling.”

Remarkably, she then extrapolates her experiment to the atmosphere:

“An atmosphere of that gas would give to our earth a high temperature; and if as some suppose, at one period of its history the air had mixed with it a larger proportion than at present, an increased temperature…must have necessarily resulted.”

As with so many women of note throughout history, her work was largely ignored until recently.

John Tyndall, a brilliant Irish physicist, has generally been quoted as the first to prove the disproportionate heating effect of CO2. There is no evidence that he knew of Foote’s work. Tyndall, being a man, was able to devote his life to science.

His apparatus allowed him to measure the capacity of the various atmospheric gases to absorb heat in the 1860s.

In the 1890s Sven Arrhenius and other Swedish scientists calculated that doubling the amount of CO2 would add 4 degrees C to global temperature. They also realised that humans could artificially cause global warming by burning fossil fuels.

In the 1950s people such as US geochemist, CJ Keeling, realised that we were transferring massive amounts of underground carbon in fossil fuels to atmospheric carbon (CO2).

This was now causing significant global heating.  Scientists started sounding the alarm bells but we are slow to act.

Perhaps increasing melting ice and snow, floods, droughts, rising seas, dying reefs, wild fires, extinctions etc. will force us to react where science didn’t.