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Data courtesy of National Snow and Ice Data Center (NSIDC)
Uploaded on Tuesday 21 Feb 2012
Trends in Arctic sea-ice extent in March (maximum) and September (minimum) in the time period of 1979–2006
Hugo Ahlenius, UNEP/GRID-Arendal
For the Northern Hemisphere (primarily the Arctic), observations using remote sensing technologies have been used to measure the extent and the to assess the development. Despite considerable year-to-year variability, significant negative trends are apparent in both maximum and minimum ice extents, with a rate of decrease of 2.5 per cent per decade for March and 8.9 per cent per decade for September (linear least squares reqression). The differences in extent are calculated as anomalies compared to the 1979-2000 average, which was 7.0 million sqkm2 in September, and 15 million sqkm2 in March. Please note that this graphic has been updated with the 2007 figures, accessible at http://maps.grida.no/go/graphic/trends-in-arctic-sea-ice-extent-in-march-maximum-and-september-minimum-in-the-time-period-of-1979-2007