Glacial retreat is being observed in North America and throughout the world, and many glaciers have completely disappeared in recent decades. About 150 glaciers were observed in Glacier National Park, Montana in 1850, and about the same number in 1910 when the Park was established. A survey of the Park in 2010 revealed only 25 glaciers.
Consequences of glacial retreat include changes in local ecosystems and water supply. Glaciers act as water reserves in the form of ice and snow, which steadily supply melt-water during the summer months. Without glaciers, ecosystems that rely on melt-water are negatively impacted. Also, ambient water temperatures are projected to rise, with negative effects for temperature-sensitive plants and animals. The US Geological Survey predicts that glacial retreat will result in more forest fires and mountain pine beetle infestations.