Category: Climate

By R. G. McKellar

Early Science.

The Swedish chemist Arrhenius published a significant advance toward the mathematical treatment of global climate in a paper published in 1896. Until that time the dynamics of a rotating planet with the familiar passing of daylight into night had defied scientists. Aarhenius devised a simplified model with the surface area of the Earth converted to a flat disc receiving solar energy at the rate of one-quarter of the incoming flux at the equator (at the equinox). All temperatures were treated as global averages—-a very difficult thing to do when most stations recording temperature were in the northern hemisphere & on land. The method employed an Ideal Atmosphere, which unfortunately did not include water vapour. Water vapour, by its volume, is the most important Greenhouse gas, and by its phase changes solid>liquid>gas>liquid>solid>gas, heat is extracted or released into the atmosphere.

Currently, all computer models use Arrhenius’ basic maths. Aarhenius arrived at the conclusion that there would be a welcome 3-4 degrees C of European warming in the 20^th century—-a very high estimate ( versus ~1degreeC later observed), and much like that coming out of climate models from various universities and meteorological offices to this day. Interestingly, Aarhenius in a 1906 paper did acknowledge the importance of water vapour, but that was subsequently over-looked .