Arctic sea ice minimum comes in at 4th lowest on record
Tuesday, September 15, 2015, 5:18 PM - After posting the smallest winter maximum on record earlier this year, Arctic sea ice has reached its summer minimum extent, which NASA and the NSIDC have logged as the the fourth lowest extent on record.
Based on satellite data and analysis from NASA and the National Snow and Ice Data Center, September 11 appears to be this year's minimum sea ice extent in the Arctic Ocean.
According to their measurements, this minimum extent comes in at just 4.413 million square kilometres, 1.87 million square kilometres lower than the 1981-2020 average of 6.283 million km2 (shown as the orange line in the image below).
This ranks as fourth lowest minimum extent on record, behind 2011, 2007 and 2012 (the lowest on record).
Unlike in 2013 and 2014, which were on an expected rebound from the record extreme low extent reached in 2012, the pattern so far for 2015 emphasizes the alarming trend for sea ice loss in the Arctic due to climate change. This is due to the pattern forming without any major weather events driving it, and with the unusual cold in the North Atlantic attributed to melting Greenland glaciers.
According to NASA:
In some recent years, low sea-ice minimum extent has been at least in part exacerbated by meteorological factors, but that was not the case this year.
"This year is the fourth lowest, and yet we haven’t seen any major weather event or persistent weather pattern in the Arctic this summer that helped push the extent lower as often happens,” said Walt Meier, a sea ice scientist with NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It was a bit warmer in some areas than last year, but it was cooler in other places, too."
The other end of the world?
Along with this Arctic minimum, the winter sea-ice maximum around the Antarctic continent is approaching. Although 2014 saw the largest sea ice extent on record in the Southern Ocean, this year is showing a September extent that's the second lowest in the past 10 years - with only 2008 showing a lower extent at this time of year.
Can it go lower?
Although, based on the values seen - with the recent uptick in sea ice - this appears to be the minimum extent for this year, it is possible that the extent could push even lower.
According to the NSIDC:
This appears to be the lowest extent of the year. In response to the setting sun and falling temperatures, ice extent will now climb through autumn and winter. However, a shift in wind patterns or a period of late season melt could still push the ice extent lower.
The agency will issue a final report in October, which will give a full accounting of the melt season, and the final, official ranking of this year's sea ice extent.