Yesterday, I profiled a new risk indicator put out by the National Snow and Ice Data Center (NSIDC). The NSIDC is providing us with a new daily updated high-frequency time series, this time on Greenland melt extent, complete with daily images that can be found here. Click on the image below to expand.
The 2012 melt season was unprecedented, with 97% of the island showing melt at one stage in July. To yesterday’s post I just wanted to add an image which brings out just how exceptional the 2012 season actually was (click for larger image), which I took from the NSIDC site. The blue dotted line gives the average melt extent over the 1981 to 2010 average. Added to what we saw with Arctic sea ice extent last summer and northern hemisphere snow cover, the Greenland melt situation shows the degree of structural change we are seeing with respect to Arctic and northern latitude climate.
A review of the year 2012 for Greenland by the NSICD can be found here. The critical question going forward is whether 2012 was a true anomaly or a harbinger of the new normal.
A similar argument was voiced some years ago over the 2007 Arctic sea ice extent retreat, with most scientists at the time urging caution over calling a trend break and suggesting that 2007 could have been a product of an unusual confluence of weather factors. After the 2012 sea ice extent retreat, which smashed the 2007 record, few would now argue against the trend being truly broken (with Arctic sea ice extent now in a state of collapse). I fear we may see a repeat performance with Greenland ice melt over the next few years.