with John Maunder
Arctic sea ice reached its annual maximum extent for 2014 on March 21. Overall, the 2014 Arctic sea ice coverage was the fifth lowest in the 1978-2014 record.
In contrast, Antarctic sea ice reached its annual minimum for 2014 on February 23. This is the fourth highest Antarctic minimum in the satellite record. This continues a strong pattern of greater-than-average sea ice extent in Antarctica for the last two years.
The National Snow and Ice Data Centre, in Boulder, Colorado, has an extensive website on Arctic and Antarctic sea ice.
Graphs of the extent of the Northern Hemisphere and Southern Hemisphere ice – updated to March, 2014 – from the above website are shown below.
These show from 1979 to 2011 the Northern Hemisphere ice extent decreased at the rate of 2.6 per cent per decade, compared with an increase of 4.5 per cent per decade during the same period in the Southern Hemisphere.
However, the Southern Hemisphere shows a relatively large variability compared with that for the Northern Hemisphere.
For further climate information, see https://sites.google.com/site/climatediceandthebutterfly/