Sunday, July 6, 2008

Global warming

The latest scientific report on climate change in my native land, Australia, sounds grim. Concerning severe droughts and scorching temperatures, the prime minister Kevin Rudd evoked a "historical assumption" that such conditions only prevailed once every twenty years or so. Well, according to the report from Australia's CSIRO [Commonwealth Scientific and Industrial Research Organisation], this situation will arise, from now on, every one to two years. That's a hell of a big difference! The report also indicates that the area affected by such conditions will be doubled. Meanwhile, Australians appear to be concerned primarily by a recent report on climate change written by an economist, Ross Garnaut. This economic report states the price to be paid by Australians in order to combat global warming... and journalists have been getting a kick out of writing in-depth and would-be witty editorials about the Garnaut conclusions. Money seems to be a more meaningful and exciting "language" than science.

In the context of talk about climate change, there's a regrettable metaphor: greenhouse effect. In our everyday world, we imagine a greenhouse as a hot and steamy microcosm in which luxuriant foliage thrives splendidly as if it were growing in an equatorial jungle.

In physical terms, a greenhouse is an extremely simple affair. The sun's rays heat the air trapped inside the structure, and a current of moist air circulates constantly through convection.

On the other hand, the complex chemical mechanisms by which obnoxious gases such as carbon dioxide cause temperatures to rise on the surface of our planet have nothing whatsoever to do with the familiar convection currents in a greenhouse. It would have been preferable if this dangerous outcome due to the presence of excessive carbon dioxide had been labeled, say, the lethal furnace effect.

Readers of my blog have heard me referring to a brilliant fellow named Joseph Fourier [1768-1830]. He was mentioned in the following three articles:

Prefects, 21 July 2007 [display];

Becoming French, 19 June 2008 [display];

— and Curious trail, 27 June 2008 [display].

My hero Fourier started out his adult life by a short and unconvincing trial period as a Benedictine monk. After achieving fame as a mathematical physicist, an Egyptologist [colleague of the Champollion brothers] and a public administrator [at the préfecture in Grenoble where I was recently naturalized], he was made a baron. Well, Joseph Fourier was a specialist in heat flow, and he was in fact the discoverer of the notorious greenhouse effect.

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