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.
The study, conducted by scientists from NASA, the University of Washington and the California Institute of Technology estimated changes from 2003 to 2008 in the total volume and thickness of what’s called multi-year ice, the yards-thick floes that can persist through a summer (here’s some video I shot while standing on a mix of old and thinner ice in 2003), and seasonal ice, which can grow to 6 feet in thickness in winter but vanishes in summer.
For a look at how this summer’s Arctic sea-ice season may unfold, visit Sea Ice Outlook 2009, where more than a dozen groups of ice researchers are posting experimental forecasts of how the ice is likely to fare. There’s a strong consensus that the season will see much less sea ice than the average for the period monitored by satellites (from 1979 onward), but is unlikely to see the extent of open water measured in 2007.
To get a sense of how the views of Arctic experts have coalesced around a rising human influence on the region’s climate, you can scan previous stories from 2001, 2005, and 2007 on ice trends and possible causes.