Evolution of understanding
Saturday, July 7, 2012
Jeremy Madden’s uninformed column (“Cool on global warming,” Aspen Daily News, July 5) is correct on one point: a single weather event or season does not a climate trend make. Nevertheless, the scientific community has amassed enormous information on climate change since Jean-Pierre Perraudin, a Swiss mountaineer and chamois hunter, deduced in 1820 that the glacier in his valley had once advanced far down that same valley. His pursuit of this insight and of Swiss scientists of his day lead directly to Louis Agassiz announcing to the world in 1837 that an ice age had occurred sometime in the past. Agassiz was one of Europe’s preeminent scientists and his endorsement of past dramatic climate change had great impact.
In the 1890s Svante Arrhenius, concerned about past climate change and the effect of fossil fuel burning, calculated the effects of halving and doubling atmospheric carbon dioxide. Carbon dioxide had been shown to absorb light and a gas which absorbs light absorbs energy and warms. Halving could cause an ice age and a doubling of atmospheric carbon dioxide would raise earth’s temperature 4-5 degrees Celsius. About right, and with a pencil and paper. A Swede, he thought a warmer country might be very nice.
The documented changes in earth’s climate and the warming threat have become clearer with the explosion of scientific knowledge about what is happening on our planet since the 1950s, especially with the increasing consumption of fossil fuels since the world has recovered from the great wars and revolutions of the first half of the 20th century. It is likely that Aspen will no longer be a ski resort within your lifetime Mr. Madden.
Therefore, to the library or bookstore: A great wander through the explosion of knowledge on past and future climate change is the book “Fixing Climate” by Wallace S. Broecker and Robert Kunzig. Professor Broecker is a major contributor to our understanding of climate change and the role of the great ocean currents in this process. He is professor emeritus at Columbia University’s Lamont Doherty Earth Observatory. Robert Kunzig, a skilled science writer, helps weave this wondrous tale making it an easy read. Shorter: “The Melting North” in the June 16, 2012, edition of The Economist. Happy reading Mr. Madden.