Much of the Arctic Ocean is covered by sea ice which varies in extent and thickness seasonally. The Arctic sea ice extent has been shrinking (during the summer) and growing (during the winter) over decades (achieving the maximum in April and the minimum in September). However a sea ice loss has been observed in recent decades. For example the average ice extent for March 2014 was the fifth lowest for the month in the satellite record which supports the idea of sea ice decline.

Monthly March ice extent for 1979 to 2014 shows a decline of 2.6% per decade relative to the 1981 to 2010 average. Credit: National Snow and Ice Data Center
In 2012, Peter Wadhams published a paper talking about how fast sea ice decline is happening:
Arctic sea ice extent had been shrinking at a relatively modest rate of 3-4% per decade (annually averaged) but after 1996 this speeded up to 10% per decade and in summer 2007 there was a massive collapse of ice extent to a new record minimum of only 4.1 million km2. Thickness has been falling at a more rapid rate (43% in the 25 years from the early 1970s to late 1990s) with a specially rapid loss of mass from pressure ridges. The summer 2007 event may have arisen from an interaction between the long-term retreat and more rapid thinning rates.
But what is exactly the Arctic ice death spiral? Continue reading