Svante August Arrhenius (19 February 1859 – 2 October 1927) was a Nobel Prize-winning Swedish scientist who made discoveries in physics, chemistry and earth science.
Originally he was a physicist, but he won the 1903 Nobel Prize in Chemistry, and was a founder of physical chemistry.
Later in life, he turned to other scientific problems. He was the first person to predict that emissions of carbon dioxide, from the burning of fossil fuels, would cause global warming.
Early work
His early work was on the conductivity of electrolytes. In 1884, based on this work, he submitted a 150-page essay on electrolytic conductivity to University of Uppsala for his doctorate. It did not impress the professors, and he received a low-class degree. Later, extensions of this work would earn him the Nobel Prize in Chemistry.
The most important idea in the thesis was his explanation that neither pure salts nor pure water is a conductor, but solutions of salts in water are.
Arrhenius' explanation was that in forming a solution, the salt splits up into charged particles (which Michael Faraday had given the name ions many years earlier). Faraday's belief had been that ions were produced in the process of electrolysis; Arrhenius' idea was that, even in the absence of an electric current, solutions of salts contained ions. He proposed that chemical reactions in solution were reactions between ions.
In an extension of his ionic scientific theory Arrhenius proposed definitions for acids and bases, in 1884. He believed that acids were substances which produce hydrogen ions in a solution and that bases were substances which produce hydroxide ions in a solution.
The Nobel Prize
About 1900, Arrhenius became involved in setting up the Nobel Institutes and the Nobel Prizes. For the rest of his life, he would be a member of the Nobel Committee on Physics and a member of the Nobel Committee on Chemistry.
He used his positions to arrange prizes for his friends (Jacobus van't Hoff, Wilhelm Ostwald, Theodore Richards) and to attempt to deny them to his enemies (Paul Ehrlich, Walther Nernst). In 1903 he became the first Swedish persn to be awarded the Nobel Prize in Chemistry.
Later work
After he had made his name, he turned to other scientific questions.
Physiology
In 1904 he delivered (at the University of California) several lectures, to try and show the application of the methods of physical chemistry to the study of the theory of toxins and antitoxins, and which were published in 1907 under the title Immunochemistry.
Earth and planetary sciences
He also turned his attention to geology (the origin of ice ages), astronomy, physical cosmology, and astrophysics, accounting for the birth of the solar system by interstellar collision. He considered radiation pressure as accounting for comets, the solar corona, the aurora borealis, and zodiacal light.
He thought life might have been carried from planet to planet by the transport of spores. This idea is now known as panspermia.
Greenhouse effect
Arrhenius thought of a theory to explain the ice ages, and in 1896 he was the first scientist to think that changes in the levels of carbon dioxide in the atmosphere could make a big change to the surface temperature through the greenhouse effect. He was influenced by the work of others, including Joseph Fourier. Arrhenius used infrared observations of the moon to work out the absorption of infrared radiation by atmospheric CO2 and water vapour. In its original form, Arrhenius' greenhouse law reads as follows: "If the quantity of carbonic acid increases in geometric progression, the augmentation of the temperature will increase nearly in arithmetic progression". This simplified expression is still used today: ΔF = α ln(C/)