Sea ice cover in the Arctic in 2011 has passed its annual minimum, reaching the second-lowest level since satellite records began, US scientists say.
The National Snow and Ice Data Center (NSIDC) says the minimum, reached on 9 September, was 4.33 million sq km.
That value is 36% lower than the average minimum for 1979-2000.
http://www.bbc.co.uk/news/science-environment-14945773