Andrew Freedman, via Climate Central
The Arctic melt season is well underway, and sea ice extent — a key indicator of global warming — declined rapidly during June, setting a record for the largest June sea ice loss in the satellite era. Sea ice extent is currently running just below the level seen at the same time in 2007, the year that set the record for the lowest sea ice minimum in the satellite era.
While the current rate of sea ice decline does not necessarily indicate that another record low will be set this year — weather conditions and other factors could slow the melt before the September sea ice minimum — so far the 2012 melt season has continued the trend of accelerated sea ice loss in the Far North.
According to the National Snow and Ice Data Center (NSIDC) in Boulder, Colo., large amounts of sea ice loss were observed during June in the Beaufort, Bering, and Kara Seas as well as Baffin and Hudson Bay. The only area with above average sea ice at the end of June was the eastern Greenland coast, the NSIDC stated.
During June, the Arctic lost a record total of about 1.1 million square miles of ice — an area about as large as the combined land area of Alaska, California, Florida, and Texas. At the end of the month, Arctic sea ice extent was 456,000 square miles below the 1979-to-2000 average. The past three years have seen the lowest June ice extents on record, and this year, sea ice loss is running about three weeks ahead of schedule. The ice extent recorded for June 30 would normally be expected on July 21, based on the 1979-2000 average, the NSIDC said.
Warmer-than-average air temperatures and a lack of snow cover helped speed the melt, according to the NSIDC. In its July 5 analysis, the NSIDC reported that a record low Northern Hemisphere snow cover extent was set for the month of June.
“This rapid and early retreat of snow cover exposes large, darker underlying surfaces to the sun early in the season,” the NSIDC reported, “fostering higher air temperatures and warmer soils.”
In general, the Arctic has been warming at a rate about twice that of lower latitudes, a trend that is expected to continue due to feedbacks in the Arctic climate system. For example, when sea ice melts, the darker ocean surface is exposed to incoming solar radiation. This warms the water and the air much more than if the brighter sea ice had remained.
Recent research has demonstrated that rapid Arctic climate change is altering the flow of weather systems across the Northern Hemisphere, raising the possibility of far-reaching consequences well south of the Arctic Circle. Increased summer sea ice loss is also helping to open the Arctic to oil and natural gas drilling, as well as increased shipping activities, which could cause further changes to the Arctic environment.
Andrew Freedman is the Senior Science Writer for Climate Central. This piece was originally published at Climate Central and is reprinted with permission.
JR: What follows is a video and excerpt from Neven’s Arctic Sea Ice blog:
When writing The dark side of Greenland, a recent blog post on decreasing reflectivity of the Greenland ice sheet, with images comparing the southwest of Greenland with satellite images from previous years, I of course realized that when that ice sheet becomes less reflective, it will soak up more solar energy and thus melt faster. But the practical aspect of this theory never really dawned on me, until I saw this video [above].
Levels in the Akuliarusiarsuup Kuua river, also knows as the Watson river, have reached such heights that they have smashed the two bridges connecting the north and south of Kangerlussuaq, a small settlement in southwestern Greenland, located at the head of the fjord of the same name. The river water stems from different meltwater outflow streams from Russell Glacier (an outflow of the Greenland ice sheet), and is a tributary of Qinnguata Kuussua, the main river in the Kangerlussuaq area.
Of course the local media are covering the story. Here are a few excerpts from different news articles from Sermitsiaq (via Google translate):
What has happened in detail over the inland ice, which caused this incident, is not yet known, but the fierce heat has certainly been an important player. And unfortunately it looks like the weather will not come to the Greenlanders’ rescue, as the air temperatures over the ice sheet are expected to remain warmer than normal at least the next 7-10 days, writes Greenland meteorological Jesper Eriksen at dmi.dk.
However, it’s not only hot on the icecap at Kangerlussuaq. Deep in the ice, there are also plus degrees:
In Greenland, it has been very hot over the inland ice in comparison to normal conditions. On July 11th at 15 UTC the recorded temperature at the Summit Camp weather station, which is located at the ice cap’s highest altitude (3200 metres), was 2.2 degrees Celsius. That is quite high for this height, particularly in light of the fact that ice has a relatively high albedo.
Just 2.2 °C doesn’t sound like much (although it looks to be a new record for July), until one realises that we are talking Summit Camp here. At an altitude of 3200 metres. In the middle of the Greenland ice sheet. Nothing but ice.
3.5 million liters of water pressed through the narrow river every second. It’s almost a doubling of previous records. It’s no wonder that a 20 ton wheel loader was torn away from the bridge in Kangerlussuaq like a toy.
JR: The rest of Neven’s post is here.