Arctic sea ice unusually thin
May 14th, 2009A British Arctic survey team has just finished a cross-Arctic survey of Arctic ice and reports:
[The data] seems to suggest it was almost all first-year ice. Our science advisors had told us to expect thicker, older ice on at least part of the route, so it is something of a mystery where that older ice has gone.
Over the length of the survey the average thickness of the sea ice was only 1.774 meters.
Peter Wadhams, head of the polar ocean physics group at the University of Cambridge, says the ice, which has been a permanent feature for at least 100,000 years, is now so thin that almost all of it will disappear in about a decade:
By 2013, we will see a much smaller area in summertime than now; and certainly by about 2020, I can imagine that only one area will remain in summer.”
Arctic ice will become seasonal, forming only during the winter.
There has been a massive decline in the amount of multi-year ice over most of the Arctic. Much of what is left of this ice accumulates in an area north of Greenland and Ellesmere Island in Canada.
Joseph Romm at Climate Progress has posted this graphic showing the extent of first year vs. older ice:
Romm emphasizes this shows ice area, not ice volume.
The NSIDC reports the spring melt season has gotten off to a slow start but is now starting to pick up.
- Click to enlarge
The NSIDC notes that the ice is unusually thin:
[T]he spring ice cover is thin and hence quite vulnerable to summer melt. However this summer unfolds, scientists expect to see high year-to-year variability in ice extent embedded within the long-term decline.
A new study shows Arctic ice extent at the end of summer can affect precipitation at lower latitudes the following winter. Slow summer sea ice extent is linked to drier winters over much of the U.S., Scandinavia, and Alaska, and wetter winters in the northern Mediterranean, Japan, and the Pacific Northwest. Extensive ice loss in summer warms the Arctic atmosphere during autumn. This warmth weakens the storm track that encircles the northern hemisphere, affecting weather patterns far away from the Arctic. As sea ice continues to decline in summer, these influences are expected to become more prominent.