Glacial Retreat

Muir Glacier and Inlet, Alaska. Mid-1890s and August 11, 2005.
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Mendenhall Glacier, Alaska 1894 and 2008.
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Grinnell Glacier, Montana. 7 July 1901 and 2009.
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Portage Glacier, Alaska. 1914 and 2004.
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McCarty Glacier, Alaska. July 30, 1909 and August 11, 2004.
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Muir and Riggs Glaciers, Alaska. August 13, 1941; August 4, 1950; and August 31, 2004.
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Pendersen Glacier, Alaska. Between the mid-1920s and early 1940s, and August 10, 2005.
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Carroll Glacier, Alaska. August 1906 and June 21, 2004.
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Northwestern Glacier, Alaska. July 1909 and 2005.
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Muir Glacier and Inlet, Alaska. Mid-1890s and August 11, 2005.

Measurements indicate a retreat of over 50 kilometers (31 miles) since original photograph in the 1890s.

Credits: Mid-1890s photograph property of L.V. Winter and P.E. Pond. 2005 photograph by Bruce F. Molnia, USGS.

Mendenhall Glacier, Alaska 1894 and 2008.

Direct measurements by the Juneau Icefield Research Program show that the glacier has retreated by more than 2800 meters since 1910 and at least 580 meters since 1948.

Credits: 1894 photograph by William Ogilvie, NSIDC/NOAA. 2008 photograph by Gary Braasch/World View of Global Warming.

Grinnell Glacier, Montana. 7 July 1901 and 2009.

Aerial measurements indicate an approximate 40% loss glacial ice area since 1966 (USGS).

Credits: 1901 by B. Willis, NSIDC/World Data Center for Glaciology. 2009 photograph by Gary Braasch/World View of Global Warming.

Portage Glacier, Alaska. 1914 and 2004.

Measurements indicate a retreat of about 5 kilometers (3.1 miles).

Credits: 1914 photograph by NOAA and 2004 photograph Gary Braasch/World View of Global Warming.

McCarty Glacier, Alaska. July 30, 1909 and August 11, 2004.

Measurements taken in 2004 indicate a retreat of over 15 kilometers (9.8 miles.)

Credits: 1909 photograph by G.S. Grant, USGS. 2004 photograph by Bruce F. Molnia, USGS.

Muir and Riggs Glaciers, Alaska. August 13, 1941; August 4, 1950; and August 31, 2004.

Credits: 1941 and 1950 photographs by William O. Field, NSIDC and Glacier Bay National Park and Preserve Archive. 2004 photograph by Bruce F. Molnia, USGS.

Pendersen Glacier, Alaska. Between the mid-1920s and early 1940s, and August 10, 2005.

Glacier retreat exceeds 2 kilometers (1.24 miles) and the lagoon in the original photograph has filled with sediment.

Credits: Original photograph undated, unknown photographer, Kenai Fjords National Park. 2005 photograph by Bruce F. Molnia, USGS.

Carroll Glacier, Alaska. August 1906 and June 21, 2004.

Photo Credits: 1906 photograph by Wright, Charles Will. From the Glacier Photograph Collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media. 2004 photograph by Molnia, Bruce F. From the Glacier Photograph Collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media.

Northwestern Glacier, Alaska. July 1909 and 2005.

Photo Credits: 1909 photograph by Grant, Ulysses Sherman. From the Glacier Photograph Collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media. 2005 photograph by Molnia, Bruce F. 2005 Northwestern Glacier: From the Glacier Photograph Collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media.

Glacial Retreat

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.