(Reuters, 7 July 2009) -- WASHINGTON - Arctic sea ice has thinned dramatically since 2004, with the older, thicker ice giving way to a younger, thinner kind that melts in the northern summer, NASA scientists reported on Tuesday. Researchers have known for years that ice covering in the Arctic Sea has been shrinking in area, but new satellite data that measure the thickness of ice show that the volume of sea ice is declining as well. That is important because thicker ice is more resilient and can last from summer to summer. Without ice cover, the Arctic Sea's dark waters absorb the sun's heat more readily instead of reflecting it as the light-colored ice does, accelerating the heating effect. Using NASA's ICESat spacecraft, scientists figured that overall Arctic sea ice thinned about 7 inches (17.78 cm) a year since 2004, for a total of 2.2 feet (0.67 metres) over four winters. Their findings were reported in the Journal of Geophysical Research-Oceans. The total area covered by thicker, older ice that has survived at least one summer shrank by 42 percent.
Posted 9 July 2009; 10:31:02 AM. Permalink
(Andrew C. Revkin/Dot Earth via New York Times, 7 July 2009) -- The thick durable sea ice that routinely cloaked much of the Arctic Ocean in colder decades in the 20th century is increasingly relegated to a few clotted places along northern Canada and Greenland, according to the latest satellite analysis of the warming region. The following video gives you a fascinating view of one patch of sea ice through 90 days, provided by a webcam left behind by researchers who annually set up camp near the North Pole to check ocean and ice conditions up close. The new analysis, published in the Journal of Geophysical Research on Tuesday, is the latest of many findings supporting the idea that the region has shifted to a new state in which seasonal ice, which forms in winter and melts in the summer, dominates. This is the main reason biologists have concerns for the long-term welfare of polar bears, which have a harder time sustaining their weight and reproducing when summertime ice is thin. At the same time, the shift bodes well for shippers, like the German company Beluga, that have plans to start sending goods from Asia to northern Europe through the fabled, but long impassible, Northern Sea Route over Russia.
Posted 9 July 2009; 9:58:58 AM. Permalink