Almost 80 years ago, on April 1938, an English steam and combustion engineer and  amateur weather-watcher, published a paper in the Quarterly Journal of the Royal Meteorological Society. His name was Guy Stuart Callendar and his paper, titled “The artificial Production of Carbon Dioxide and its Influence on Temperature”, was going to be one of the most influential papers on climate change science.

Born in Canada in 1898, Callendar earned a certificate in Mechanics and Mathematics in 1922 at City & Guilds College and at the time he published his seminal paper was employed as a steam technologist by the British Electrical and Allied Industries Research Association. A keen meteorologist, interested in climate, Calendar spent his spare time gathering temperature and weather data from around the world. He made all the calculations by hand in his home, in West Sussex, England, and his measurements were so accurate that “they were used to correct the official temperature records of central England”.

Decades before the effects of global warming became widely debated, Callendar showed that “an unprecedented warming trend” was taking place in the first decades of the twentieth century. He estimated that man had added about 150,000 million tonnes of carbon dioxide (CO2) during the past half century and the planet had undergone warming on the order of one degree Fahrenheit (0.5 degrees Celsius). In his paper, Callendar recognised that

“Few of those familiar with the natural heat exchanges of the atmosphere which go into the making of our climates and weather would be prepared to admit that the activities of man could have any influence upon phenomena of so vast a scale…..”

yet he hoped “to show that such influence is not only possible, but is actually occurring at the present time.”He concluded that the rising temperature trend was due to anthropogenic increases in the concentration of atmospheric carbon dioxide, primarily through the processes of combustion.

 

Callendar also argued that the oceans act as a “giant regulator of carbon dioxide and holds some sixty times as much as the atmosphere”. Recent estimates have calculated that 28 percent of all the carbon released as CO2 from fossil fuel burning and land-use changes over the decade 2002–2011 went to plants, roughly 46 percent to the atmosphere and 26 percent was absorbed by the oceans, but with a cost.  When CO2 dissolves in seawater it forms carbonic acid and as more CO2 is taken up by the ocean’s surface, the pH decreases. The seawater becomes more acidic, a phenomenon called ocean acidification.

Although Callendar included in his paper future projections of future carbon dioxide emissions and levels, as Svante Arrhenius before him, he  appealed the idea of atmospheric warming. Concluding his article he speculated that the combustion of fossil fuels “is likely to prove beneficial to mankind in several ways, besides the provision of heat and power…..  Small increases of mean temperature would be important at the northern margin of cultivation, and the growth of favourably situated plants is directly proportional to the carbon dioxide pressure. In any case the return of the deadly glaciers should be delayed indefinitely.”

Callendar published his discoveries in a series of papers, but they did not raise any interest from the scientific community at the time. Only, later, in 1957, just before the beginning of the International Geophysical Year (IGY), Hans Seuss and Roger Revelle referred to the “Callendar effect,” defining it as “climatic change brought about by anthropogenic increases in the concentration of atmospheric carbon dioxide, primarily through the processes of combustion.” Despite his fundamental contributions to climate science, Guy Callendar is still relatively unknown.

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References and further Reading

James Rodger Fleming, The Callendar Effect

Guy Stewart Callendar, “The Artificial Production of Carbon Dioxide and Its Influence on Temperature”, inside the “Critical Concepts in the Environment” edited by Frank Chambers and Michael Ogle, Rutledge(October, 2002):45-46

James Roger Fleming “What Role Did G.S. Callendar Play in Reviving the CO2 Theory of Global Climate Change?” Presidential Symposium on History of Meteorology, American Meteorological Society, Long Beach, CA, Feb. 2003.