Update on Greenland
Extent of surface melt over Greenland’s ice sheet on July 8 (left) and July 12 (right). Measurements from three satellites showed that on July 8, about 40 percent of the ice sheet had undergone thawing at or near the surface. In just a few days, the melting had dramatically accelerated and an estimated 97 percent of the ice sheet surface had thawed by July 12. In the image, the areas classified as “probable melt” (light pink) correspond to those sites where at least one satellite detected surface melting. The areas classified as “melt” (dark pink) correspond to sites where two or three satellites detected surface melting.
High pressure systems have parked themselves over Greenland in late spring and early-mid summer 2012 breaking temperature records and melting record amounts of surface ice. In late May, the inland town of Narsarsuaq, Greenland hit an unprecedented 76.6°F (24.8°C) and in late July again went up to 74°F. The western town of Kangerlussuaq hit a record 75°F on July 10th. In fact, many parts of Southern Greenland have been in the 70s for consecutive days this spring and summer. But what has scientists reeling is a ridge of warm air that sat over Greenland from July 8th through July 11th and caused melting to occur on over 97% of the surface of Greenland's ice sheets. Prior to this year, satellites have never shown more than 55% of Greenland's ice sheets with surface melt during the summer months. Yet this year, not 50%, but almost 100% of the entire ice cover of Greenland, from its thin coastal edges to its two-mile-thick center, experienced some degree of melting at its surface. Although much of the melt water quickly refreezes in place, along the coast some of that melt water is bound to find its way into the sea. Scientists say this rare large-scale melt has happened before. In 1889 a similar type of melt occured according to ice core records. That 1889 event was the last time any surface melt was seen at Summit Station which sits upon 2 miles of ice in the center of Greenland, until now 123 years later. Combine this year's events with the total ice sheet mass loss in 2011, which was 70% larger than the 2003 – 2009 average annual loss rate of -250 gigatons per year, and we are starting to see a cumulative affect that is worrisome.*
An ice island drifts away from the Petermann Glacier, July, 2012.
This most recent calving has an area of roughly 120 sq km (46 sq mi), that is about half the size of the iceberg that broke off the same glacier in 2010. earthobservatory.nasa.gov
PBS interview with Thomas Wagner.
The town of Tiksi, Siberia, Russia which is close to the Laptev Sea is also experiencing temps in the 70s this summer.