Between 1932 and 2005, this is what the retreat of Boulder Glacier in Glacier National Park looked like. Losing glaciers isn't merely a cosmetic alteration of landscape or inconsequential. The winnowing of ice sheets has coincided with rising temperatures, less snowpack and snow melting earlier, large forest fires and lower flows in rivers come summer. Photo illustration courtesy Greg Pederson/USGS
Between 1932 and 2005, this is what the retreat of Boulder Glacier in Glacier National Park looked like. Losing glaciers isn't merely a cosmetic alteration of landscape or inconsequential. The winnowing of ice sheets has coincided with rising temperatures, less snowpack and snow melting earlier, large forest fires and lower flows in rivers come summer. Photo illustration courtesy Greg Pederson/USGS