Record Low September Arctic Sea Ice Now Appears Unlikely in 2016

Brian Donegan
Published: August 4,2016
Due to a cool and stormy Arctic in July, ice melt in the Arctic Ocean was slightly slower than average through the month, so a new record low September ice cover is now appearing unlikely in 2016.
The month with the least amount of ice in the Arctic Ocean is typically September, since the ice has been melting the entire summer. The ocean then starts cooling off, with more ice reforming, beginning in October.

Arctic sea ice cover for July 2016 averaged 3.14 million square miles. The magenta line shows the 1981-2010 median ice cover for July. The black cross indicates the geographic North Pole.

Although the ice melt was slightly slower than average last month, the amount of Arctic sea ice was still the third-lowest for July in the satellite record, according to the National Snow and Ice Data Center (NSIDC).
The ice extent averaged 3.14 million square miles, which is 73,000 square miles above the previous July record low set in 2011, but 637,000 square miles below the 1981-2010 average.
July is only the second month so far this year that has not featured record-low ice cover in the Arctic, NSIDC says.
The average rate of ice loss per day in July is 33,500 square miles per day, and last month's rate was slightly below average at 32,400 square miles per day, according to NSIDC.
Temperatures at the 925-millibar level of the atmosphere (around 2,500 feet elevation) were 2-4 degrees Fahrenheit above average along the northern coasts of Alaska, Canada and Greenland, but that wasn't quite warm enough to completely melt out the thick sea ice typical of that region.
From 1979-2016, the rate of ice loss in July is 28,070 square miles per year, or 7.3 percent each decade, NSIDC says. July 2016's ice cover remained above 2011's record-low levels, but it was below 2007's near-record-low levels during the first half of the month.

Average July Arctic ice cover from 1979-2016 shows a decline of 7.3 percent per decade.

According to a recent analysis by NOAA at NSIDC, it can be concluded that the current downward trend in Arctic sea ice is the most extreme in records dating back to 1850, in both duration and scale of ice loss. Other than the Bering Sea, no areas of the Arctic Ocean have seen ice cover as low as in the past decade.

Weather Pattern Shift

A major change in the weather pattern occurred over the Arctic in June. High pressure dominated the region through the first five months of the year, but the pattern shifted to lower-than-average pressure by June.
Extra cloud cover kept temperatures down and slowed the ice-melting process.
The June pattern shift was associated with a developing large bubble of high pressure south of Alaska over the northeastern Pacific Ocean, which formed in the middle of May.
The NSIDC says the pattern shift may be related to a shift in the Pacific Decadal Oscillation (PDO) over spring and early summer this year.