Today, sea ice in the Arctic continued what is shaping up to be a truly historic melt.
Sea ice area fell to 2.364 million square kilometers as sea ice extent fell to 3.614 million square kilometers. These measures reported by Cryosphere Today and JAXA are the lowest in the satellite record.
Looking at the sea ice, you will notice that many ship passages are open through the Arctic. Most of the Canadian Archipelago is clear of sea ice and a broad swath of ocean north of Russia is also clear.
Though melt trends do appear to be slowing, a daily retreat of ice at this time of year is very unusual. And this is just what we’re still experiencing. Given this inexorable melt, we should entertain the possibility that sea ice will continue to fade past the average cessation date on September 15th. And an extended period of melt this year would exacerbate already staggering losses.
There are a number of factors at play currently enhancing end-season melt. However, these factors are all long-term, and appear to have over-ridden the short-term influence of weather. The conditions that so dramatically enhanced melt in 2007 were not present through most of this year. So it is only possible to blame this year’s melt on increasing long-term Arctic heat content and the current fragility of the sea ice.
In a recent interview with the BBC, sea ice expert and Cambridge Professor Peter Wadhams noted that Arctic sea ice was ‘headed for oblivion’ within ten years and that the added heat absorbed by the darker Arctic Ocean was like adding ’20 years of CO2′ emissions.
Overall departures from previous historic lows are as follows (last record year in parenthesis):
JAXA Extent: -636,000 square kilometers (2007)
Cryosphere Today Area: -541,000 square kilometers (2011)
PIOMAS Volume: -400 cubic kilometers (2011)
NSIDC Extent: -659,000 square kilometers (2007)