On August 24, 2012, the Japanese Space Agency showed a new record low for sea ice extent. The next day, NSIDC and all other agencies measuring sea ice extent also showed record lows. In the above image, you can see a comparison between 2007 and 2012 for August 24th of this year.
A week before, Arctic sea ice area also set a new record low. Sea ice volume measured by PIOMAS has yet to be recorded for August. But this measure is also likely to see new record lows when published.
About two and a half weeks remain for the normal melt season, which usually ends around September 15th. And since Friday we have continued to see melt in both sea ice area and extent.
Today, sea ice area set a new record low at 2,643,000 square kilometers. This measurement is 262,000 square kilometers below the previous record low set in 2011.
The Japanese Space Agency (JAXA) also continued to reach new record territory with sea ice extent showing 4,000,625 square kilometers. This value is more than 250,000 square kilometers below the record low set in 2007.
On Friday, JAXA issued a statement predicting sea ice extent could fall below 4 million square kilometers before the end of this season. Given the rapid melt since Friday, it seems likely that sea ice extent could fall below 4 million square kilometers by tomorrow or the next day, and perhaps far less by the middle of September.
It is worth noting that melt for the 2007 record year ended nearly ten days later than during a normal season. So it is possible that 2012 will also extend melt beyond mid-month. Though the pace of sea ice area melt has slowed, indicating some consolidation of the ice sheet, sea ice extent measurements have plummeted at an average rate of about 80,000 square kilometers per day for the past few days.
With both area and extent pushing into new record territory almost daily, we can reasonably expect new lows beyond the values currently seen. Best estimates for new sea ice area lows are in the range of 2.1 million square kilometers to 2.6 million square kilometers and 3.6 million square kilometers to 4.0 million square kilometers for extent.
The rates of decline for the Arctic this year have been startling for many reasons. Not only has melt far exceeded that seen in 2007, it has also occurred during periods of weather that wouldn’t normally result in a rapid melt. This result shows that Arctic sea ice has grown very fragile. This apparent fragility has become clearer even as more scientists note the possibility for ice free periods in the Arctic within 10 years, 20-30 years sooner than even the most rapid forecasts and as much as 90 years sooner than the more conservative models.
These results are, indeed, startling and will require further explanation in another blog.