Valdosta State University Researcher Investigates Cause of MeltingGlaciers in Montana

The Grasshopper and Castle Rock glaciers in the Beartooth Mountains of Montana have lost over half their surface areas in the past century, said Dr. Edward Chatelain, associate professor and head of the Physics, Astronomy, and Geosciences Department at Valdosta State University, in his presentation at the 117th annual meeting of the Geological Society of America (GSA). The presentation, which was held on October 19 in Salt Lake City, Utah, addressed the scientific question of whether the documented melting was episodic or continuous. Chatelain examined aerial and surface photographs that indicate dramatic ice-margin loss in specific small cirque glaciers during the last hundred years, which can be directly tied to historic weather cycles in the region.

Through careful study of the data, his research documented ice-margin losses between the years 1898 and 1952 and again between 1953 and 2001, with a decrease of 50 percent or more in both periods. However, his findings show the ice-margin losses result from a cyclic trend of inconsistent seasonal weather conditions and not necessarily a result of global warming, as some might predict.

Chatelain's research suggests that ideal weather conditions for glacier formation are when precipitation is high and temperature is low, as in the period spanning 1950 to 1977. However, changes in the temperature and precipitation variables result in different outcomes, as seen in the early part of the century when high temperatures were combined with prolonged low precipitation, resulting in the most significant ice-margin loss.

Results of Chatelain's study indicate that the major episodes of ice-margin loss were 1933 to 1937 and 1983 to 1988, with minor events occurring during several other periods. The most severe episode was 1933 to 1937, where prolonged record summer temperatures were followed by five consecutive winters of record low precipitation. Counter to what most believe, the research suggests that the most severe episode is earlier in the century and not recent years�as in the publicized extreme temperatures of the late 1980's and the early 1990's�which have received the greatest alarm or concern.

Pictured above is the Castle Rock glacier nestled inside the Beartoth Mountains of Montana

"It's easy to believe that the earth's temperature is continually increasing; however, when you factor in the variable of precipitation, you can offset the effects of temperature," said Chatelain. "It's more complicated than just temperature�we must consider precipitation."

Another consideration, according to Dr. Chatelain, is the first appearance of El Ni�o in winter of 1976-1977, which appears to be the major influence on precipitation. During an El Ni�o year, the precipitation amounts in the study area consistently tend to be low.

"It is an honor to be invited and a good chance to present my research in front of my colleagues and peers," Chatelain said, who was able to utilize a Faculty Research Grant from VSU to purchase many of the aerial and satellite photos required for the study and a Faculty Presentation Grant from the Center for Faculty Development for his travel to the meeting in Salt Lake
City, Utah.