http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/07/18/snow-and-arctic-ice-extent-plummet-suddenly-as-globe-bakes/
The headline may be a bit over-dramatic, but the Post has got it essentially right. And they call attention to some troubling climate patterns outside the Arctic as well.
“NOAA and NASA both ranked June 2013 among the top five warmest (NOAA fifth warmest, NASA second warmest) Junes on record globally (dating back to the late 1800s). But, more remarkable, was the incredible snow melt that preceded the toasty month and the sudden loss of Arctic sea ice that followed.”
The ice melt season got off to a slow start this year, due to an unprecedented two-week Arctic-wide cyclone that kept temperatures low, dumped snow on the ice and shaded it from the spring sun. But it also fractured and crushed the icecap, opening leads and and shoving the ice around. Which effect will swing the balance remains to be seen. Right now, the melt appears to be catching up with a vengeance. We are on track for a very low-ice September, although it is still too early to tell whether or not we will beat last year’s extraordinary all-time record breaker. July numbers, as you can see from the graph, are a poor predictor of September values.
http://www.ijis.iarc.uaf.edu/seaice/extent/Sea_Ice_Extent.png
Since we began measuring ice extent by satellite, (1979) the September average low sea ice extent has broken all previous September records in ’84,’85,’90,’95,’02,’05,’07 and 2012. Summer ice extent is driven by other factors besides global warming, many of them local and unpredictable, and some of them parts of feedback mechanisms, both positive and negative, that we don’t fully understand, or have even identified. A record low ice year is a perfect storm, everything falls on the same side of the balance at once, and an unlikely event. This is why we have only had one back-to-back pair of record-breakers (’84 and ’85). Still, it cannot be ruled out for this year, and even if we don’t break the 2012 record, the long term trends are clear.
These are the September minimums for the last 8 years (in millions of square kilometers).
2005: 5.57
2006: 5.92
2007: 4.30
2008: 4.73
2009: 5.39
2010: 4.93
2011: 4.63
2012: 3.61
But it’s the trends that matter, not isolated events or statistical outliers.. Here are the 10-year averages for September polar low-ice extents in the last 4 decades:
’80s average 7.4
’90s average 6.8
’00s average 5.7
’10s average 4.4 (last 3 years only)
I don’t think the climatologists are going to have any trouble getting their funding renewed for the next few years.
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Nothing that hasn't happened before.
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Why are the numbers in square km?
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Sea ice rarely gets more than a few meters thick.
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That explains it, thanks
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That explains it, thanks
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Ice cover can be determined directly by satellite measurement.
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Thanks n/t
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Thanks n/t
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Volume/thickness
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Thanks n/t
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Thanks n/t
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Sea ice rarely gets more than a few meters thick.