Scientists at the University of Colorado have followed the extent of the Arctic ice cap with satellites since 1979. Never before has the maximum winter extent of the sea ice been smaller than March 2011, according to the findings published at the portal of the National Snow and Ice Data Centre.
Climate scientists believe shrinking sea ice in the Arctic is due to global warming resulting from emission of climate gasses from human activities. Winter temperatures across the Arctic were anomalously warm this winter, reaching 2 to 6 degrees Celsius about normal in January.
Polar bears rely on sea ice for survival. Less sea ice complicate hunting for seals.
The sea ice maximum was on March 7th with 1,2 million square kilometers below the 1979 to 2000 average, according to the data from the National Snow and Ice Data Center at the University of Colorado.
- I think one of the reasons the Arctic sea ice maximum extent is declining is that the autumn ice growth is delayed by warmer temperatures and the ice extent is not able to ‘catch up’ through the winter, says Walt Maier, quoted by Science Daily. Maier says he is not surprised by the date since the scientists have seen a downward trend in winter sea ice over the last decades.
With less sea freezing in the winter, the existing ice becomes more vulnerable to melting in the summer. The question is when we may eventually see ice-free summers around the North Pole.