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          These two images show the Gaisbergferner Glacier above the village of Obergurgl in the upper reaches of the Ötztal (the valley of the Ötz River) in the Austrian land of Tirol. The upper image is a drawing from page 165 of Die Gletscher der Ostalpen by Dr. Eduard Richter, published in 1888 by J. Engelhorn of Stuttgart. The lower image is from a slide taken on the morning of 25 July 2003.

          The two images do not provide quite the same perspective, but comparison shows that the Gaisbergferner was smaller in 2003 than it was at the time of the drawing. One can easily see that the tributary glaciers flowing onto the main Gaisbergferner in the 1888 drawing no longer flow onto the main glacier in 2003, so that they have become glacierets or hanging glaciers. If one uses the width of the mouths of those tributary glaciers (now hanging valleys) as a measure, it becomes evident that the length of the main glacier down-valley has also decreased. In fact, Railsback and his students have observed a decrease in the glacier's length from 1997 to 2003, in that a path from the ridge on the right in this image led onto the glacier in 1997 but only led to the meltwater stream in 2002 and 2003.

          The significance of sequential images like these documenting glacial retreat is that they provide natural non-instrumental evidence of global warming. Skeptics of global warming argue that world climate is not getting warmer, and that instrumental (thermometer) records of rising temperatures are only the result of increasing temperatures at busy airports and in urban heat islands. Retreating glaciers, however, are not at airports or in urban heat islands, and so cannot by so easily dismissed by those skeptics. The retreat of these glaciers, which is widespread around the world, is independent evidence of global warming.

 

 


This page is part of the Tirol Glacier Image Collection Project.


e-mail to Railsback (rlsbk@gly.uga.edu)
Railsback's Alpine & Glacial Geology course web page
Railsback's main web page
UGA Geology Department web page