Image caption
Pedersen Glacier, at Aialik Bay in Alaska’s Kenai Mountains, in 1917 (left) and 2005 (right). In the early 20th century, the glacier met the water and calved icebergs into a marginal lake near the bay. By 2005, the glacier had retreated, leaving behind sediment that allowed the lake to be transformed into a small grassland. Photos courtesy of Louis H. Pedersen (1917) and Bruce F. Molina (2005), obtained from the Glacier Photograph Collection, Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology.