NASA: Melting sea ice opens the Northwest and Northeast Passage
NASA: Sea ice melt opens the Northwest and Northeast Passage
mongabay.com
September 9, 2008
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An image released by NASA shows that Arctic sea ice has retreated to the point where both the Northwest Passage around North America and the Northern Sea Route around Russia are open simultaneously. The occurrence marks the first time on record that both passages have been open.
Last month the National Snow and Ice Data Center (NSIDC) reported that Arctic sea ice extent has rearched the second-lowest level since record-keeping began. NSIDC said that in the final weeks of the melt season, the sea ice extent could challenge the record-low of 1.59 million square miles set last year.
Researchers say shifting currents and warmer waters are triggering ice melt, a process which builds on itself since sea ice helps reflect sunlight back into space, cooling the region. When sea ice melts, the dark areas of open water absorb the sun’s radiation, trigger a positive feedback loop that worsens melting. When there is less cloud cover, the effect is intensified.
 This image shows Arctic sea ice concentration on September 8, 2008, as observed by the Advanced Microwave Scanning Radiometer–Earth Observing System (AMSR-E) sensor on NASA’s Aqua satellite. The observations are collected on a pixel by pixel basis over the Arctic. The percentage of a 12.5-square-kilometer pixel covered by ice is shown in shades of dark blue (no ice) to white (100 percent ice). The gray line around the Arctic basin shows the median minimum extent of sea ice from 1979-2000. NASA image created by Jesse Allen, using data obtained courtesy of the National Snow and Ice Data Center (NSIDC). Caption by Rebecca Lindsey. |
Environmentalists are concerned that the loss of summer sea ice could have dramatic implications for wildlife — like polar bear and walrus — that depend on pack ice for feeding. At the same time, some developers welcome declining ice cover in that it could make it easier to exploit the Arctic’s rich mineral, oil and gas deposits. Melting has already triggered a scramble between Canada, Russia, the U.S., Denmark, Sweden and Norway over rights to seabed resources.