billw55, on 2015-February-25, 12:36, said:
Billw,
Over the long term, the short term increase is smaller, but not insignificant (+1.2 vs. -3.1 million sq. km). Over the intermediate term (2007-2015), there is no discernable trend. While the sea ice has expanded and contracted over that timeframe, quite erradicately, the extent is comparable to where it was eight years ago (there was a large one-year decline from 2006 to 2007). One could argue that the large decline in 2007 was an overshoot, and the sea ice has simple corrected for it over the past eight years. This did not stop several scientists from using that short-term decline to make bold predictions about an ice-free Arctic sometime this decade.
In the decade prior, Arctic sea ice was declinely slowly. Using the current regression since 1998, which amounts to the highest projected loss rate, the Arctic would be ice-free (< 1M sq. km.) in ~25 years. Employing longer-term regression analyses, it would take significantly longer.
Before the 1990s, sea ice had reached a maximum, and was holding steady for at least a decade. Prior to the satellite data in 1979, sea ice data is less certain, although evidence suggests that the ice increased from ~1940-1970. If the sea ice extent is on a more cyclical pattern, then an ice-free Arctic would not occur this century, if ever.
If you examine the data, the sea ice anomaly has remained in a much tigher range over the past three years, compared to the previous six. Whether the sea ice resumes its downward spiral or regenerates, is uncertain. However, the recent hiatus (to borrow the global warming term) in sea ice decline is evident from the data:
http://arctic.atmos....maly.arctic.png