Arctic Sea Ice Reaches Year's Minimum
Spring's not all about pretty flowers and greening trees. For some scientists it means watching Arctic ice. Scientists and engineers with NASA's Operation IceBridge are already at it, surveying glaciers in Greenland, Alaska and northern Canada. The flight part of the largest aerial survey of Earth's polar ice ever flown – a six-year mission over both poles aimed at producing a three-dimensional view of Arctic and Antarctic ice sheets, ice shelves and their sea ice.
Here, NASA's P-3B sits on the tarmac of the Kangerlussuaq Airport. The plane is equipped with a suite of instruments that gather data as the plane flies over the ice. It also carries scientists and teachers, some of whom took the following images.
The glacial Alaskan mountains are seen from high altitude aboard the P-3B during the IceBridge flight from Thule, Greenland, to Fairbanks, Alaska, on March 21, 2013.
A true river of ice, or glacier, on Greenland's Geikie Peninsula.
Tongue-shaped moraines appear to lick at the Penny Ice Cap on Baffin Island, Nunavut, Canada. These moraines are debris that was plowed up and left behind by past glaciers
Another moraine left by a small glacier on Penny Ice Cap on Baffin Island, Nunavut, Canada.
This year's aerial survey of the Penny Ice Cap glacier follows previous radar surveys done in 1995, 2000 and 2005 using the Airborne Topographic Mapper and CReSIS radar instrument.
Near Thule Air Base, sled dogs rest on the sea ice in North Star Bay. Behind them is the 700-foot-high Mount Dundas. Cities in Greenland are connected by ship and air, but shorter distances are crossed by snowmobile or dogsleds.
No, not another glacier, but an ice-covered fjord on Baffin Island near Davis Strait, which is in the distance. Baffin Island is the fifth largest island in the world.
This is a mosaic image of sea ice in the Beaufort Sea. The darkest zone is open water. Light blue zones are thick sea ice, while dark blue zones are thinner ice. The image was created by the Digital Mapping System (DMS) instrument aboard the IceBridge P-3B.
Icebergs crowd the sea ice of Jakobshavn Fjord, seen from NASA’s P-3B aircraft on the Apr. 4, 2013, IceBridge survey. Jakobshavn Glacier produces one in ten Greenland icebergs and is one of the fastest moving ice streams in the world.
NASA / DMS
Another view of the cracked Beaufort Sea ice by the Digital Mapping System (DMS) instrument aboard the IceBridge P-3B. The DMS uses a camera that points down through a window in the underside of the plane. It snaps a frame each second which are combined into a mosaic.
On April 8, 2013, science teacher Mark Buesing of Libertyville High School in Libertyville, Ill., shoots Greenland glaciers through the window of NASA's P-3B.
Eastern Greenland's Helheim Fjord is surveyed on April 5, 2013, from the NASA P-3B. Helheim is one of the largest in Greenland.
The P-3B sees its shadow on April 9, 2013, on the sea ice southeast of Greenland. Flying low altitude is all part of gathering detailed ice data.
Danish high school science teacher Jette Rygaard Poulsen watches the Greenland ice roll by from a window of the P-3B airborne laboratory on Apr. 8, 2013.
Not everything is icy in Greenland. Even as early as April 8, southwestern Greenland has ice free fjords.
An actively calving glacier front on the ocean in southwestern Greenland on April 8.
In two plots of topographic data from the Jakobshavn Glacier warmer colors are higher ice elevation. The calving front is at the transition from warm to cool colors. The difference between the two dates of survey reveal a loss of about 200 meters of ice.
It doesn't affect the ice, but there are some other interesting sights in Greenland this spring, like the aurora borealis over Kangerlussuaq.
The sea ice that covers the surface of the Arctic Ocean has begun to slowly increase with the end of the northern summer and the onset of fall. The National Snow and Ice Data Center (NSIDC) announced on Friday that the summer melt season reached its end on Sept. 13, with Arctic sea ice extent at 5.1 million square kilometers (1.97 million square miles).
That, notes NSIDC, is “substantially more” than last year’s record low of 3.41 million square kilometers (1.32 million square miles), “yet sea ice extent remains quite low compared to the long-term 1981 to 2010 average.”
NSIDC observes that, whereas the previous six summers have experienced high sea level pressure over the Beaufort Sea and Greenland, and low sea level pressure over Eurasia a, combination that helps to transport warm air into the Arctic — this past summer was characterized by low sea level pressure over the central Arctic and Greenland. As a consequence, temperatures were cooler and sea ice melted less. (There was also less surface ice melt on Greenland.)
Climate change skeptics leaped on the recovery, with the Daily Mail’s in-house denier-in-chief, David Rose, claiming that “some eminent scientists now believe the world is heading for a period of cooling that will not end until the middle of this century.”
Rush Limbaugh asserted that “there is a record amount of Arctic ice for this time of year.”
Yes, well. It’s a record since 2009, yes. Otherwise, not so much. In fact, it’s the sixth lowest on record, and would have been a record low in 2006. This Washington Post blog underlines the point with seven visuals, and Dana Nuccitelli at the Guardian provides his usual detail in this dissection of the “Arctic-ice-has-recovered-everything’s-fine” brigade.
Writing in his “Bad Astronomy” blog at Slate, Phil Plait used the analogy that a rebound from the exceptionally low levels of 2012 “is like getting a D- after getting an F.” And as this video retort by science journalist Peter Hadfield points out, “There are always peaks, dips and wobbles in every trend. So although we’ve had 35 years of declining Arctic ice cover, it obviously isn’t going to move in a straight line.”
Prior to 2012, for example, 2007 set a record low in summer sea ice extent; but that extent increased in 2008, and then increased some more the following year, leading some skeptics to claim that there was nothing to worry about, sea ice was recovering. Then the minimum extent decreased again in 2010, declined some more in 2011 and crashed to a new low in 2012. Focusing on the inevitable occasional yearly recoveries while ignoring the long-term downward trend produces a misleading and confusing picture.
It also ignores the fact that sea ice extent is just part of the story. Sea ice volume is also decreasing rapidly, as old, thick, multi-year ice is replaced by thin, first-year ice, which is more susceptible to melt the following summer.
New data from the European Space Agency’s Cryosat satellite shows there has been a decrease in the volume of winter and summer ice over the past three years, and that the volume of the sea ice at the end of last winter was lower than any other year going into summer.