Glacier research presented yesterday (May 26) in Boston at the conference of the American Geophysical Union, and reported today on the AP Wire, raises a number of quite obvious questions. The research was done by Mark Meier and colleagues at the University of Colorado at Boulder. Here are our comments, followed by the AP story:
1. The AP story doesn't say (and perhaps the Meier research paper doesn't say either) how the rate of glacier recession varied over the last century. If recession was initially rapid and then slowed, then it is very likely the result of the rapid rise in temperature between 1860 and 1940 as the Earth recovered from the Little Ice Age--and not from any global warming due to higher concentrations of CO2.
And indeed there is some evidence of that. The World Glacier Monitoring Service in Zurich, Switzerland, in a paper published in Science in 1989, noted that between 1926 and 1960 more than 70 percent of 625 mountain glaciers in the [mid-latitude] United States, Soviet Union, Iceland, Switzerland, Austria, and Italy were retreating. After 1980, however, 55 percent of these same glaciers were advancing.
2. To take the average recession rate over the last century and extrapolate that rate out over the next 50-70 years (if that's what Meier et al have done) is highly unscientific. Not only would that conceal important information (the recession rate variations) but, as the above WGMS paper shows, such forecasts are unreliable.
3. As glaciologist Keith Echelmeyer of the University of Alaska's Geophysical Institute noted in September 1997 ( when Vice President Albert Gore made an issue of glacier recession in Glacier National Park): "To make a case that glaciers are retreating, and that the problem is global warming, is very hard to do. The physics are very complex. There is much more involved than just the climate response." Echelmeyer pointed out that, in Alaska, some large glaciers continue to advance in the very same areas where most are retreating.
4. It is difficult to tell from the AP story whether Meier's claims about sea level, beach erosion, and floods ("rivers jumping their banks") are actually addressed in his paper or just his opinion of the moment.
Two researchers with the U.S. Geological Survey looked specifically at U.S. flood patterns since 1914 in a paper presented at the American Geophysical Union conference in San Francisco in December 1997. Studying measurements from river gauges, they found no increase in floods in the United States in the years since 1914. Moreover, they concluded that greater flood damage (and insurance claims) in recent years stemmed largely from the growth of urban construction in flood-prone areas. (See the report from Science magazine at www.sepp.org/controv/floods.html )
5. While there is some warming going on in northern mid-latitudes--evident in both the ground-based and satellite global temperature records--its appearance has not been consistent with greenhouse theory, which posits the greatest warming at the poles. (The Antarctic, in July 1997 and April 1998, posted record cold temperatures).
One possible explanation--the focus of an annual scientific conference hosted by NASA over the last several years--is the regional effect of commercial airline traffic. Some studies, including one by S. Fred Singer, conclude that thin cirrus clouds created by airline contrails create a regionally enhanced greenhouse effect. (See the press release on Singer's abstract, and the graphs, at www.sepp.org/pressrel/jun26.html ) Commercial airline traffic has been increasing at the rate of 5 percent per year. Cirrus are unrelated to concentrations of CO2.
6. Finally, the AP reporter's closing sentence is misleading. At current U.S. emission rates, a 5 percent decrease in greenhouse emissions below 1990 levels will amount, by 2010, to a decrease in emissions of more than one-third.
In any case, here's the Associated Press story, reported today.
THE ASSOCIATE PRESS, Wednesday, 27 May, 1998
"Global warming speeding up glaciers' melting"
BOSTON (AP) -- All of the glaciers in Glacier National Park in Montana will be gone in the next 50 to 70 years, according to researchers who have been measuring the rate that glaciers are melting around the world. Those glaciers are melting faster than scientists had previously thought, according to the study by geologist Mark Meier, who presented his findings at a meeting of the American Geophysical Union in Boston on Tuesday. "The glaciers are receding and they're becoming thinner, and you can see this," Meier said, placing the blame squarely on global warming. The melting ice caps are contributing to rising sea levels that lead to beach erosion and more severe inland storms, he said. And rivers are jumping their banks more often as a result. Meier and his research team at the University of Colorado at Boulder looked at characteristics of glaciers worldwide during the last 100 years, then compared the measurements to today's ice caps. They found that mid-latitude glaciers -- those outside of Antarctica and Greenland -- had receded and become thinner. In the last century, the largest glacier on Mount Kenya in Africa has lost 92 percent of its mass, and the glaciers in Russia's Caucasus Mountains have shrunk by half, Meier found. In 40 years, the Tien Shan Mountain range between China and Russia has lost 22 percent of its ice. Though glaciers outside arctic regions account for only 6 percent of the world's ice, they contribute more heavily to sea-level changes. In December 1997, leaders of 38 nations pledged to cut greenhouse gas emissions, mainly carbon dioxide, by slightly more than 5 percent from 1990 levels.
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