Willi Dansgaard in Memoriam

The research he initiated produced the most compelling empiral evidence of the carbon-temperature relationship

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Willi Dansgaard in Memoriam

Willi Dansgaard, the great Danish paleoclimatologist, died on January 8. His passing has received remarkably little notice in the world press, though the New York Times published an appreciative obituary today. Were there a Nobel Prize in the earth sciences, he surely would have been a recipient. As it was he had to content himself with the Tyler Prize, the highest award given for environmental research, which he shared with Hans Oeschger, the Swiss glaciologist with whom his work was closely linked, and Claude Lorius, a French scientist.

It was Dansgaard who discovered that the temperature of the earth's atmosphere could be inferred from the isotopic composition of rainwater and snow, and who then realized that the past temperatures of the atmosphere could be extracted from ice cores. Oeschger made himself the world's foremost expert on the measurement of carbon dioxide and other gases found in ice cores. Their work led eventually to a complete year-by-year reconstruction of the earth's climate going back a million years, through a handful of ice ages, showing a powerful linear relationship between greenhouse gas levels and temperatures. Lorius led a team that produced an early version of that record, going back hundreds of thousands of years, based on drilling in Antarctica.

Dansgaard and Oeschger also discovered cycles in which drastic climate changes were found to occur much more rapidly than anybody had imagined--on the scale of decades, rather than hundreds or thousands of years. Though Dansgaard was a rather apolitical person, the discovery of abrupt climate change put it on the global agenda, leading to language in the Rio Framework Convention on Climate Change calling for measures to prevent "dangerous" climate change.

It's regrettable that we don't have a Nobel prize in the geosciences, and not merely for personal reasons. There's altogether too little appreciation of the fact that a revolution occurred in the earth sciences in the second half of the twentieth century, as science historian Spencer Weart has observed, and that the study of the biosphere remains one of the most dynamic of the physical sciences today. Yet earlier this week the Washington Post published an excellent article detailing how most of the major U.S. satellites dedicated to monitoring changes on the Earth's surface and in its atmosphere are behind schedule and under-funded. These include the Global Precipitation Measurement mission, the latest Landsat satellite, Hydros, and the NPOESS satellite set.

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