NOAA's National Centers for Environmental Information
Sea Ice Extent
| August 2017 | Sea Ice Extent | Anomaly 1991-2020 | Trend per decade | Rank (39 years) | Record | ||||
|---|---|---|---|---|---|---|---|---|---|
| million km² | million mi² | Year(s) | million km² | million mi² | |||||
| Northern Hemisphere | 5.48 | 2.12 | -14.77% | -11.51% | Largest | 36th | 1983 | 8.19 | 3.16 |
| Smallest | 4th | 2012 | 4.72 | 1.82 | |||||
| Southern Hemisphere | 17.22 | 6.65 | -3.48% | +0.78% | Largest | 37th | 2014 | 18.91 | 7.30 |
| Smallest | 3rd | 1986 | 17.00 | 6.56 | |||||
| Globe | 22.70 | 8.76 | -6.47% | -2.47% | Largest | 39th | 1982 | 25.93 | 10.01 |
| Smallest | 1st | 2017 | 22.70 | 8.76 | |||||
Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2017 (39 years)
According to the National Snow and Ice Data Center (NSIDC), the Northern Hemisphere (Arctic) sea ice extent — which is measured from passive microwave instruments onboard NOAA satellites — averaged for August 2017 was 5.51 million square km (2.13 million square miles), 1.77 million square km (680,000 square miles), or 24.3 percent, below the 1981-2010 average. This was the third smallest August Arctic sea ice extent since records began in 1979. Only the August Arctic sea ice extents in 2007 and 2012 were smaller. Regionally, sea ice extent was much below average on the Pacific side of the Arctic, particularly in the Beaufort, Chukchi, and East Siberian Seas. In the Beaufort Sea at the end of August, the sea ice extent was further north than at any point in the 1979-present record. Sea ice concentration and extent was also below the 1981-2010 average in the Canadian Archipelago, but both the northern and southern passages of the Northwest Passaged continued to be blocked by ice at the end of August. Near-average ice extent was observed in the Barents Sea with slightly below-average ice extent in the neighboring Kara and Greenland Seas. Although ice melt is expected to continue for a few more weeks in the Arctic, it is unexpected that the minimum extent will set a new record. Overall, August Arctic sea ice extent is decreasing at an average rate of 10.2 percent per decade.
The August Southern Hemisphere (Antarctic) sea ice extent was 17.50 million square km (6.76 million square miles), which was 650,000 square km (250,000 square miles), or 3.6 percent, below the 1981-2010 average. This was the second smallest August Southern Hemisphere sea ice extent on record. Only the August Antarctic sea ice extent in 2002 was smaller at 17.49 million square km (6.75 million square miles). The rate of ice growth was not consistent throughout August, with ice growth nearly stopping for several days at the beginning and end of the month. Southern Hemisphere August sea ice extent is increasing at an average rate of 0.6 percent per decade, with substantial inter-annual variability.
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.