Svante August Arrhenius

Svante August Arrhenius: The Man Who Calculated Global Warming

He spent a year of his life doing arithmetic by hand — tens of thousands of calculations, no machine to help — to answer a question nobody had asked properly: what happens to the temperature of the Earth if you change the amount of carbon dioxide in the air? The answer he arrived at in 1896, that doubling it would warm the planet by about four degrees Celsius, is close enough to the modern estimate to be uncomfortable. He also thought this would be rather a good thing.

An Arithmetical Prodigy at Vik

He was born on 19 February 1859 at Vik, near Uppsala, to Svante Gustav Arrhenius, a land surveyor employed by Uppsala University, and Carolina Thunberg. At three he taught himself to read. Watching his father keep the books, he turned into an arithmetical prodigy — a skill that would matter more later than anyone could have guessed. He entered the local cathedral school at eight, straight into the fifth grade, and graduated in 1876 as its youngest and ablest pupil.

Uppsala University disappointed him. He disliked the physics teaching and had no patience for the chemist Per Teodor Cleve, and in 1881 he left for Stockholm to work at the Physical Institute of the Swedish Academy of Sciences under Erik Edlund.

The Dissertation They Nearly Failed

In 1884 he submitted a hundred-and-fifty-page thesis on the conductivity of electrolytes, containing fifty-six separate theses. Its central claim was heretical: that when a salt dissolves in water it splits of its own accord into charged particles — ions — present in the solution whether or not any current is passing through it. Faraday had held that electrolysis created ions in the first place. Arrhenius said they were already there.

His examiners, Cleve among them, were unimpressed. The dissertation was awarded a fourth-class degree, upgraded to third class after he defended it — a mark that in practice closed the door on an academic career. Most of the fifty-six theses are still, with minor modification, considered correct.

He posted copies abroad. Rudolf Clausius, Wilhelm Ostwald and Jacobus Henricus van 't Hoff read them and were electrified. Ostwald travelled to Uppsala in person to offer him a job in Riga. Arrhenius turned it down — his father was gravely ill, and died in 1885 — but a travel grant then put him on the road, working with Ostwald in Riga and Leipzig, Friedrich Kohlrausch in Würzburg, Ludwig Boltzmann in Graz, and van 't Hoff in Amsterdam. It was as good an education in the new physical chemistry as existed anywhere, and he had assembled it out of rejection.

The Equation and the Prize

At Leipzig in 1889, working alongside Ostwald, he produced the formula that carries his name. The Arrhenius equation describes how the rate of a chemical reaction depends on temperature and on activation energy — the barrier molecules must clear before they can react at all. It is one of the load-bearing relations of chemical kinetics, used daily from industrial process design to estimating the shelf life of a drug.

He became a lecturer at Stockholm University College in 1891, professor of physics in 1895 over the objections of several colleagues, and rector in 1896. In 1903 the Nobel Prize in Chemistry went to him for the theory of electrolytic dissociation — the ion theory the Uppsala examiners had graded fourth class. He was Sweden's first Nobel laureate.

One Year of Arithmetic

The 1896 paper, "On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground," is the one that outgrew him. Arrhenius wanted to know whether swings in atmospheric carbon dioxide could explain the ice ages. He took Samuel Langley's measurements of the intensity of moonlight, made between 1885 and 1887, and used them to derive how strongly water vapour and carbon dioxide absorb heat. Then he worked out mean temperatures and humidities across the globe, and calculated what would happen at 67, 150, 200, 250 and 300 per cent of the carbon dioxide level of his own day. The work took him a year of hand computation.

His conclusion was a rule of thumb still cited: if the quantity of carbonic acid increases in geometric progression, the temperature will rise nearly in arithmetic progression. Doubling carbon dioxide, he found, would warm the Earth by roughly 4°C; quadrupling it, by about 8°C. He was building on Fourier, Pouillet and Tyndall, but he was the first to put physical chemistry to work on the number.

The 1896 paper itself said little about burning coal. That came in his popular book *Worlds in the Making* (1908), where he judged human emissions large enough to warm the planet — and welcomed the prospect. Warming, he argued, would stave off the next ice age and improve harvests in the cold north. Rising seas do not appear in his ledger.

Empire and Its Uses

From 1901 he sat in the Royal Swedish Academy of Sciences and, for the rest of his life, on the Nobel Committee for Physics and in effect on the chemistry committee too. He used the position: he pushed allies toward prizes and worked to block rivals. In 1905 he founded the Nobel Institute for Physical Research in Stockholm and ran it until his retirement in 1927.

His later curiosity roamed. He turned to physiological chemistry and showed that reactions in living tissue obey the same laws as reactions in a flask; his 1904 California lectures on toxins and antitoxins became *Immunochemistry* (1907). He wrote on ice ages and astrophysics, and floated the panspermia hypothesis, that life might drift between planets as spores. Less creditably, he sat on the board of the Swedish Society for Racial Hygiene, founded in 1909 — an association that belongs in any honest account of him.

Why Svante Is Called a Genius

The case is not primarily one of raw brilliance but of independence of judgment sustained against institutional verdict. The ion theory was marked fourth class by professional chemists and turned out to be right; Ostwald, van 't Hoff and Clausius saw immediately what Uppsala could not, and the Nobel Committee agreed nineteen years later. That is a rare thing to be right about, in the teeth of that much expert opposition, at twenty-five.

The climate work displays a different faculty: patience of a kind almost nobody now possesses. There was no conceptual trickery in the 1896 paper — the greenhouse mechanism had been described by Fourier and measured by Tyndall. What Arrhenius supplied was the willingness to grind out a year of hand calculations to convert a qualitative effect into a number, and the sensitivity figure he got is startlingly close to what supercomputers produce today.

The counter-case is substantial. His climate estimate was partly lucky: it rested on Langley's moonlight data and on simplifications that later scientists rejected, and for decades the consensus dismissed his result as too crude to trust. His interpretation of what warming would mean was wrong — he thought it a benefit. And his Nobel Committee conduct was factional, his racial hygiene involvement discreditable. He was a formidable calculator and an exceptionally stubborn thinker; the word genius fits his refusal to accept a bad verdict better than it fits any single flash of insight.

Afterlives

He died in Uppsala on 2 October 1927 of an acute intestinal illness. The honours had come thickly before that: the Davy Medal in 1902, the first Willard Gibbs Award in 1911, the Faraday Lectureship in 1914, the Franklin Medal in 1920, foreign membership of the Royal Society in 1910.

Craters on the Moon and Mars carry his name, as do Arrheniusfjellet in Svalbard and the Arrhenius Laboratories at Stockholm University. And in a coincidence that has not gone unnoticed, the climate activist Greta Thunberg's father, Svante Thunberg, was named for Arrhenius, a cousin in the family line.

Achievements

• Foreign Member of the Royal Society — 1910
• Nobel Prize in Chemistry — 1903
• Franklin Medal — 1920
• Davy Medal — 1902
• Held posts at Riga Technical University, Stockholm University and Uppsala University
• Educated at Stockholm University and Uppsala University
• Fields of research: chemistry and physics