The 2008 Arctic sea ice melt season ended a few weeks ago (mid-September) and is now in a state of growth and renewal as fall brings forth cooler temperatures, diminishing sunlight and the eventual on set of winter. To that end, Arctic sea ice will grow in both size and thickness till sometime next March when it reaches its maximum extent.
What has become increasingly interesting in the scope of the Arctic and more specifically sea ice melt in relation to global warming is the accelerated pace of sea ice decline in the past few years. The 2008 sea ice season teetered with last year’s record figures but eventually came up slightly short (~390,000 square kilometers), while the 2007 melt season record broke the 2005 figures.
Putting numbers aside for a moment, scientists from across the globe have become increasingly concerned that previous estimates that put a “summertime ice-free Arctic” in the later half of this century have begun to revise their estimates, which are now in the 2013 – 2030 time-frame. The primary concern that is driving a shift in refocusing such estimates lies in the amount of thick, dense multi-year sea ice remaining in the Arctic Ocean. Multi-year sea ice is a primary factor which has managed the longevity of the Arctic polar ice mass, which some experts believe to have been in place for more than 1 million years.
As of 2008, approximately 30% of the total sea ice extent in the Arctic is composed of multi-year sea ice, where thinner first year sea ice now dominates the landscape. First year sea ice is prone to melt during the summer months and therefore will likely give rise to an increased possibility of passing on record minimum sea ice extent figures to successive melt seasons.
See Deteriorating Arctic section for further information: