Glaciers and Glacial Warming: Arctic
Glaciers and Glacial Warming: Arctic
ArcticIce Under Fire: Arctic
Geophysicist Tom Osterkamp, Denali Park, Alaska
Geophysicist Tom Osterkamp indicates ground level when he installed this temperature probe pipe near Denali Park, 15 years ago.
Alaska permafrost temperature has increased 0.5° to 1.5° C since 1980, when Osterkamp began measuring ground temperature at 30 sites. Many of those sites show thermokarsting like this. Serious effects include forest damage, sinking roads and buildings, eroding tundra riverbanks, changes in tundra vegetation, and increased carbon dioxide and methane emissions from thawed peat.
tundra
Just how serious a threat thawing tundra can be is being measured in Northern Sweden.
Rising atmospheric temperatures are causing the disappearance of permafrost and its replacement with marshland or open water. At Stordalen Mire near Abisko National Park, where careful records and aerial photos were available for comparison, the amount of wetland increased more than 50 % at the expense of higher dry land which had been underlain by permafrost. Study leader Patrick Crill reports this has increased the emission of methane from the mire, a powerful greenhouse gas, by as much as two-thirds over 1970 emissions. A 2004 study by Torben Christensen and others directly measured hydrocarbon emissions from the Mire, and found that almost all the emissions were methane. The scientists express concern that methane emissions seem to increase with temperature and could be a positive feedback creating even more atmospheric warming.
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