Arctic Sea Ice extended its fall into record low territory for two out of three major indexes today. JAXA sea ice fell by about 26,000 square kilometers to touch 3.569 million square kilometers of sea ice extent. Cryosphere Today showed another fall in sea ice area to 2.24 million square kilometers, a drop of 23,000 square kilometers from the day before. NSIDC continued to hover within 30,000 square kilometers of the record low it set on Wednesday.
The end to a typical melt season is now just one day away. However, sea ice melt trends, with new lows being set on a daily basis, make it highly uncertain that melt will end by that date. Given the current rates of decline, and the highly volatile nature of this year’s melt season, it appears possible that new record lows for at least some sea ice measures will continue beyond the 15th. And considering the fact that a somewhat robust melt is still occurring over certain parts of the sea ice, there does appear to be a possibility that melt may extend for a substantial period beyond the traditional date for end of melt.
Departures from past record lows are growing ever larger. Here is a list (last record year in parenthesis):
JAXA Extent: -681,000 square kilometers (2007)
Cryosphere Today Area: -665,000 square kilometers (2011)
PIOMAS Volume: -400 cubic kilometers (2011)
NSIDC Extent: -750,000 square kilometers (2007)
All values are now approaching or have exceeded the 700,000 square kilometer loss mark and it would only take a single anomalous melt day to push the NSIDC extent loss over 800,000 square kilometers. The amount of melt for 2012 has now approached but not exceeded the record losses of 2007 when more than a million square kilometers of sea ice were lost in one year. However, percent losses are much closer to the 2007. NSIDC has now seen an 18% drop in sea ice extent. Cryosphere Today has seen a 24% drop in sea ice area. These percent losses are roughly equal to those of 2007 which saw falls in the low to mid 20% range.
Looking at the sea ice, we can see continued rapid losses in the region of the Laptev sea even as a slow growth is occurring north of Canada and Alaska. The balance between the melt and freeze in these respective regions will likely determine losses or gains in sea ice over the days to come.
Temperatures for the region above the 80th parallel continue to show a slow decline. But the rate of drop is much, much slower than normal for this time of year. Last week temperatures were about 3 degrees C above average for this time of year. Now, they are about 4 degrees C above average. This slow rate of temperature decline combined with a number of influences likely transporting heat energy into the Arctic are likely contributing to continued ice sheet declines so late in the season. However, the underlying factor for all these extreme and unprecedented events continues to be human caused global warming.
And just for fun… I’ve posted this relevant video for Rocketboom. Enjoy: