Any day now, the annual thaw of Arctic sea ice will peak and make it official: the minimum extent of ice in 2013 will be the sixth lowest since satellite monitoring began in 1979.

Arctic sea ice extent as of 16 September (shown in white) is smaller than the average annual minimum recorded between 1981–2010 (outlined in orange).{credit}National Snow and Ice Data Center/NASA Earth Observatory{/credit}

That is according to scientists at the US National Snow and Ice Data Center (NSIDC) in Boulder, Colorado, who expect to declare an official minimum in the next few days. As of 16 September, the last date for which data are available, sea-ice extent stood at 5.10 million square kilometres — roughly 50% higher than the staggering all-time record set last summer, but still well below the 1981–2010 average.

But that brief reprieve does not signal a recovery of Arctic sea ice, which is steadily shrinking as the climate warms. Every year since 2007 ranks somewhere on the list of the top six lowest ice extents, according to the NSIDC. And this year, by early August, sea-ice cover was already lower than annual lows recorded in the 1970s and 1980s, despite cooler temperatures and kinder cyclones.

The ice is also thinning. Overall, its volume declined 36% in autumn and 9% in winter over 2003–12, according to a recent analysis of data collected by the European Space Agency’s Cryosat probe. This past winter, ice volume stood at less than 15,000 cubic kilometres, the lowest value ever recorded by Cryosat, according to results released last week by Andrew Shepherd, an ice expert at the University of Edinburgh, UK.