In 2007 the rate and extent of sea ice melt shocked the world of climate scientists. That year an unusual set of weather events combined to produce a record sea ice melt in the Arctic Ocean. This year, 2012, that record is almost certainly going to be broken, if not shattered. What makes this VERY unusual is that the recent conditions in the Arctic, including an Arctic cyclonic storm, normally produce slower sea ice melt conditions, not the record-pace conditions observed over the past several weeks.
The National Snow and Ice Data Center and NASA show that as of yesterday (8-23-2012) the sea ice extent in the Arctic Ocean is already at near record levels.
This map shows the current area of the Arctic Ocean covered by at least 15% sea ice as of 8-23.
If you follow my blog you've certainly seen maps like this before. The white area shows sea ice cover, while the orange line shows the historical average (1979-2000) sea ice cover for this date. As you can see, the amount of sea ice currently existing in the Arctic is WAY below average, and it has been for the past several years.
What makes this year different, however, is the rate and extent of sea ice melt - it's going crazy!
Normally the Arctic reaches maximum sea ice melt sometime in mid to late September. The graph below shows some interesting things. The dark gray line shows the historical rate of Arctic sea ice melt (1979-2000). The light gray area aound that line shows + 2 standard deviations (i.e., the range that contains 95% of all sea ice extent observations during that 1979-2000 time period). The dashed green line shows the pattern of sea ice melt during the previous record year, 2007. The blue line shows the pattern of sea ice melt this year, 2012.
As you can see, the sea ice extent in the Arctic is already within a hair's breadth of setting a new sea ice melt record. That this would happen is not a surprise to climate scientists anywhere...what IS a surprise, though, is how early we reached this mark this year. We are still anywhere from two to three weeks from the date when we observe the maximum sea ice melt for a given year.
As for the record for this date, the sea ice melt for 2012 is somewhere between 500,000 km2 and 750,000 km2 greater (that's that much less ice) than in the previous record year of 2007! Only time will tell now by how much the old record will be broken, but if this year's pattern holds it could be more than a record-breaking year, it could be a record-smashing year.
I'll keep you posted as the melt season progresses.