Formation and Evolution
The Aletsch Glacier resulted from the accumulation and compaction of snow. Glaciers generally form where snow and ice accumulation exceeds snow and ice melt. As the snow and ice thicken it reaches a point where it begins to move due to a combination of gravity and pressure of the overlying snow and ice.
During the last glacial periods, the Aletsch Glacier was much larger than now. 18,000 years ago the lower part of the ridge, between Riederalp and the glacier, was completely covered by ice. Only the summits of the Bettmerhorn, Eggishorn and the Fusshörner were above the glacier. After an important retreat, the glacier again advanced 11,000 years ago during the last glacial period. The glacier reached the Rhone valley, and its ice the Riederfurka. Remaining moraines are still visible in the Aletsch Forest.
Since the last glaciation, the glacier generally retreated. However slight climatic changes happened and, in 1860, the glacier was 3 km longer and the ice level 200 m higher.
As for many other glaciers, records show a major longer-term retreat trend.
On August 18th, 2007, photographer Spencer Tunick used hundreds of naked people in a "living sculpture" on the Aletsch Glacier in a photo shoot intended to draw attention to global warming and the shrinking of the world's glaciers. The temperature was about 10 °C (50 °F) at the time of the photo shoot. The 600 participants on the shrinking glacier volunteered for Tunick (a collaboration with Greenpeace) to let the world know about the effects of global warming on the melting Swiss glaciers. The Aletsch Glacier receded by 100 m (330 ft) between 2005 and 2006.
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