12B. ClimateChange

49 arctic summer sea ice fig 42 northern snow cover

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Unformatted text preview: d over the past 50 years, leading to higher surface water temperatures as well as at depth Higher sea temperatures stress tiny animals that make up corals, leading to coral bleaching and death Fig. 4.9 Arctic summer sea ice Fig. 4.2 Northern snow cover Fig. 4.18 Greenland ice sheet Fig. 4.15b, Glaciers Fig. 4.18 Antarctic ice sheet UNIPCC AR4 WG1 Climate Trends - Melting Ice Retreating Alaskan Glacier Glacier National Park, Montana Documenting Glacial Retreat and Loss As climate warms and drought becomes more persistent, climate models predict by 2030 GNP loses all of its glaciers. Glaciers in place by 7,000 years ago; grew to maximum during Little Ice Age ~ A.D. 1850. 150 glaciers in 20th century; in 2005 - 27 glaciers remain. Grinnell Glacier reduced by 90% area this past century. Decline in ice tied to increase in mean summer temperature and reduction in winter snowpack. Boulder Glacier Glacier National Park, MT 1932 T. J. Hileman photo courtesy of GNP archives 2005 USGS Repeat Photography Project http://nrmsc.usgs.gov/repeatphoto/ Greg Pederson photo USGS Grinnell Glacier Glacier National Park, MT 1910 Fred Kiser photo courtesy of GNP Archives 2008 USGS Repeat Photography Project http://nrmsc.usgs.gov/repeatphoto/ Lisa McKeon photo, USGS Grinnell Glacier Glacier National Park, MT T. 1938 ourtesy J. Hileman photo C of GNP Archives 1981 Carl Key photo USGS 1998 D. Fagre photo USGS 2006 Karen Holzer photo USGS Oblique view of Grinnell Glacier taken from the summit of Mount Gould, Glacier National Park. The relative sensitivity of glaciers to climate change is illustrated by the dramatic recession of Grinnell Glacier while surrounding vegetation patterns remain stable. USGS Repeat Photography Project http://nrmsc.usgs.gov/repeatphoto/ Sperry Glacier Glacier National Park, MT 1930 circa Morton Elrod photo K. Ross Toole Archives Mansfield Library, UM 2008 Lisa McKeon photo, USGS Repeating Elrod’s photograph from the same photo point was impossible since he shot from the elevated perspective of the glacier’s surface. The terminus of the glacier has retreated beyond the field of view, but these images give a sense of the glacier’s extent and mass early in the 20th century. USGS Repeat Photography Project http://nrmsc.usgs.gov/repeatphoto/ Melting Glaciers According to a UN climate report, Himalayan glaciers that are source...
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