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Global Snow & Ice - July 2013

Sea Ice Extent

July 2013 Extent
(per decade)
(out of 35 years)
million km2 million mi2 Year(s) million km2 million mi2
Northern Hemisphere 8.45 3.26 -12.89% -7.22% Largest 31ˢᵗ 1983 10.91 4.21
Smallest 5ᵗʰ 2011 7.91 3.05
Southern Hemisphere 17.13 6.61 +4.20% +0.97% Largest 2ⁿᵈ 2010 17.20 6.64
Smallest 34ᵗʰ 1986 15.82 6.11
Globe 25.58 9.88 -2.10% -2.07% Largest 24ᵗʰ 1979 27.30 10.54
Smallest 11ᵗʰ 2011 24.23 9.36
Ties: 2005

Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2013 (35 years)

According to the National Snow and Ice Data Center (NSIDC), the Northern Hemisphere sea ice extent — which is measured from passive microwave instruments onboard NOAA satellites — averaged for July 2013 was 8.45 million square km (3.26 million square miles), 12.85 percent below the 1981-2010 average, and the fifth smallest July Arctic sea ice extent on record. The sea ice extent during July 2013 was about 540,000 square kilometers (208,000 square miles) above the record low monthly value in 2011. Over the course of the month, the average sea ice loss was 105,000 square kilometers (41,000 square miles) per day, which was faster than average for the month and second only to July 2007. The Arctic lost ice rapidly during the first half of July and the ice melting slowed towards the end of the month. Over the long-term, the Arctic is losing July sea ice at an average rate of 7.4 percent per decade. Similar to the rest of 2013 to date, below average sea ice was observed on the Atlantic side of the Arctic, with near and slightly above average ice coverage in the Beaufort and Chukchi seas and along the Russian coast.

The July 2013 Southern Hemisphere sea ice extent was 17.13 million square km (6.61 million square miles), 4.22 percent above the 1981-2010 average. This marked the second largest July Antarctic sea ice extent on record, behind the record large July extent of 17.20 million square km (6.64 million square miles), set in 2010. July Southern Hemisphere sea ice extent is increasing at an average rate of 1.0 percent per decade, with substantial interannual variability.

When combining the Northern Hemisphere and Southern Hemisphere sea ice extents, the globally-averaged sea ice extent during July was 25.58 million square km (9.87 million square miles). This was 570,000 square km (220,000 square miles), or 2.2 percent, below the 1981-2010 average of 26.13 million square km (10.09 million square miles) and the 12th smallest global July sea ice extent since records began in 1979.

For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.

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Citing This Report

NOAA National Climatic Data Center, State of the Climate: Global Snow & Ice for July 2013, published online August 2013, retrieved on April 17, 2014 from http://www.ncdc.noaa.gov/sotc/global-snow/2013/7.