By August 14- 2019, extent started tracking above levels observed in 2012, resulting in the second lowest August extent in the satellite record. Although Arctic air temperatures are now falling below freezing, sea ice loss will likely continue for several weeks as heat stored in the ocean melts the underside of sea ice. Winds can also compress the pack further reducing sea ice extent. As of this post, the rate of sea ice loss has sped up again.
On August 14, Arctic sea ice extent began tracking above 2012 levels, and continued to do so for the remainder of the month, resulting in a monthly average extent of 5.03 million square kilometers (1.94 million square miles). This is 310,000 square kilometers (120,000 square miles) above the 2012 average extent, the lowest in the satellite record, and 2.17 million square kilometers (838,000 square miles) below the 1981 to 2010 average for August. On August 13, ice extent dropped below 5 million square kilometers (1.9 million square miles). This never occurred prior to 2007, but has occurred every subsequent year apart from 2009 and 2013. Overall sea ice retreat during the second half of August was modest, taking place along the periphery of the ice edge within the Arctic Ocean. Sea ice concentrations remain low over many areas, especially along the ice edge in the Beaufort Sea and within the Laptev Sea.
For the month as a whole, sea ice loss was most pronounced in the East Siberian Sea as the ice that had persisted in that region finally melted out. The ice edge is presently far north of its climatological average position everywhere except for a tongue of ice in the eastern part of the Beaufort Sea west of Banks Island, and around the island of Svalbard, where the ice edge remains near or slightly south of its average location for this time of year. While sea ice concentrations from the passive microwave record suggest that the Northwest Passage southerly route, or Amundsen’s route, is free of ice, operational ice analyses, which employ higher resolution visible band and radar satellite data, show some remaining ice around the Prince of Wales Island. The more northerly route through the Parry Channel and M’Clure Strait still has significant amounts of ice and will likely not open this year.
On August 31, sea ice extent dropped to 4.62 million square kilometers (1.78 million square miles), the third lowest extent for this date in the satellite record.
Overall, the pace of ice loss in August 2019 was 54,900 square kilometers (21,200 square miles) per day. This was considerably slower than the 2012 rate of decline of 89,500 square kilometers (34,600 square miles) per day, but only slightly slower than the 1981 to 2010 climatological rate of decline of 57,300 square kilometers (22,100 square miles) per day. In total, 1.70 million square kilometers (656,000 square miles) of ice were lost during August 2019. The linear rate of sea ice decline for August from 1979 to 2019 is 76,200 square kilometers (29,400 square miles) per year, or 10.59 percent per decade relative to the 1981 to 2010 average.
