Climate controversies (of the nineteenth century)

A hundred and fifty years ago today a gifted child called Svante Arrhenius was born in the Uppsala region of Sweden. Self-taught in reading and arithmetic by the age of three – or so it is said – young Svante went on to study at the Swedish Academy of Sciences, where his dissertation included more than fifty original theses and the seed of work that would later win him a Nobel Prize for Chemistry. (The dissertation received a third-class mark, nonetheless, so maybe there's hope for the rest of us yet.)

Among Arrhenius's most important scientific achievements was an 1896 paper entitled On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground. Published in Philosophical Magazine, this paper pinned down the workings of the greenhouse effect and laid the scientific basis for the emissions cuts being debated to this day.

Earlier figures such as Joseph Fournier and John Tyndall had suspected the air warmed the earth by absorbing infrared energy. In the words of Tyndall, seemingly a scientist who harboured literary ambitions, the atmosphere "is a blanket more necessary to the vegetable life of England than clothing is to man. Remove for a single summer-night the aqueous vapour from the air … and the sun would rise upon an island held fast in the iron grip of frost."

Arrhenius took the science to a whole new level by showing that the power of the atmosphere's warming effect was determined by the amount of carbonic acid (CO2) it contained. He predicted that if the amount of CO2 in the atmosphere doubled, then the temperature would rise by around 5–6 degrees – not a world away from today's figure of 2–4.5 degrees.

It took a huge amount of work to reach this conclusion, but Arrhenius knew he was fighting an important scientific battle. "I should certainly not have undertaken these tedious calculations if an extraordinary interest had not been connected with them", he barked in the paper.

Arrhenius was well aware of one of the key implications of his research: that the burning of fossil fuels was likely to warm the planet. However, partly because he had no way to predict the meteoric rise in global fossil fuel consumption over the following hundred years, he wasn't worried about the possibility that man-made global warming might rapidly render the planet uninhabitable. On the contrary, he was optimistic that it might prove helpful by delaying the next ice age.

So Arrhenius didn't get everything right. And his involvement in "racial biology" – which blazed a trail for compulsory sterilization and eventually Nazi eugenics – doesn't help his legacy.

Nonetheless, the world should be grateful for the insights of this remarkable man, not least because he made his key contribution to science at considerable personal expense. As Rob Kunzig writes in Fixing Climate, Arrhenius's "ravishing young wife", Sophia, left him in 1894, half way through his greenhouse number crunching. Clearly Svante wasn't the only one who found his calculations tedious.