Sea Ice Extent
|July 2017||Sea Ice Extent||
(out of 39 years)
|million km2||million mi2||Year(s)||million km2||million mi2|
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 July 2017 was 8.21 million square km (3.17 million square miles), 1.58 million square km (610,000 square miles), or 16.14 percent, below the 1981-2010 average. This was the fifth smallest July Arctic sea ice extent since records began in 1979. The July 2017 Arctic sea ice extent was 270,000 square kilometers (104,000 square miles) above the previous record monthly low set in 2011. Regionally, sea ice extent was below average on the Pacific side of the Arctic, particularly in the Beaufort, Chukchi, and East Siberian Seas. Sea ice extent was closer to average on the Atlantic side of the Arctic. July Arctic sea ice extent is decreasing at an average rate of 7.3 percent per decade.
The July Southern Hemisphere (Antarctic) sea ice extent was 15.73 million square km (6.07 million square miles), which was 740,000 square km (290,000 square miles), or 4.49 percent, below the 1981-2010 average. This was the smallest July Southern Hemisphere sea ice extent on record, dropping below the previous record of 15.82 million square km (6.11 million square miles) set in 1986. The rate of ice growth was fairly constant throughout July with some slowing of ice expansion mid-month. Southern Hemisphere July sea ice extent is increasing at an average rate of 0.9 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.