Canadian Ice Shelves Breaking up at High Speed
As Patrick Lockerby noted back in April:
The oldest non-glacial ice in the northern hemisphere is a small remnant of the former Ellesmere Ice Shelf which began forming about 5500 years ago. That remnant is breaking up. Where the ice shelf has vanished the fjords are free of perennial ice for the first time in 3000 to 5500 years. It seems likely that very soon the oldest non-glacial ice will be a mere 5 years old, or less.
And in the seminal paper by Polyak et al 2010, History of sea ice in the Arctic, it says:
The severity of present ice loss can be highlighted by the breakup of ice shelves at the northern coast of Ellesmere Island, which have been stable until recently for at least several thousand years based on geological data.
Here are the visuals (found on this web page from Carleton University):
Map of Ellesmere Island ice shelves on August 8th 2005: Ice shelves are outlined in black. Blue denotes the coast of Ellesmere Island. Left to Right: Serson, Petersen, Milne, Ayles, Ward Hunt and Markham, MODIS images from the Rapid Response Project at NASA/GSFC. Maps courtesy of Derek Mueller, Carleton University.
By July 21st 2011 the Serson Ice Shelf was divided into Serson A and B. The Ayles and Markham Ice Shelves had completely disappeared:
After this year's melting season Serson B is all but gone on August 26th 2011, and now it's the large Ward Hunt Ice Shelf that has been divided into a western and eastern part.
Again, from the Carleton University web page:
The Serson Ice Shelf was reduced from 205 km2 to two separate remnant sections in 2008: Serson A, a 42 km2 floating glacier tongue and Serson B (35 km2) just to the north. This past summer, the Serson A was reduced to a 25 km2 and the Serson B was reduced to 7 km2.
Last year, the Ward Hunt Ice Shelf was 340 km2 with its central area broken into pieces. This past summer, the central area disintegrated into drifting ice masses, leaving two separate ice shelves: a western (227 km2) and an eastern (74 km2) Ward Hunt Ice Shelf.
In 1906, the Ellesmere Island ice shelves were an estimated 8900 km2 and were reduced to 1043 km2 over the last century. The total extent of Ellesmere ice shelves is now 563 km2 or 54 per cent of what it was prior to the loss of the Ayles Ice Shelf in August 2005.
Edit: Below in the comments Michael Fliss has some great links with animations of calving events of various shelves in 2008.
And here's the accompanying press release:
(Ottawa) – Canadian ice shelves are changing at an unexpected rate, with almost 50 per cent lost in the last six years, experts say.
Carleton University’s Derek Mueller says this summer has resulted in the near-complete loss of one important ice shelf and the largest remaining shelf separated into two distinct remnants.
“This is our coastline changing,” says Mueller, a researcher in the Department of Geography and Environmental Studies. “These unique and massive geographical features that we consider to be part of the map of Canada are disappearing and they won’t come back.”
After taking stock of this summer’s changes using satellite imagery, Mueller notes that the ice shelves have declined appreciably nearly every summer since 2005. This rapid attrition will have lasting effects, he says.
This summer alone, most of the Serson Ice Shelf broke away and the Ward Hunt Ice Shelf has now split into two separate pieces. This ice loss equals up to three billion tonnes or about 500 times the mass of the Great Pyramid of Giza.
“Since the end of July, pieces equaling one and a half times the size of Manhattan Island have broken off,” says Luke Copland, researcher in the Department of Geography at the University of Ottawa. He warns that oil companies need to sit up and take notice as more icebergs will be floating down from the North and may threaten rigs in locations such as the Beaufort and Chukchi seas.
Mueller blames a combination of warmer temperatures and open water for recent ice shelf calving. “The ice shelves were formed and sustained in a different climate than what we have now. As they disappear, it implies we are returning to conditions unseen in the Arctic for thousands of years.”
Arctic ice shelves, old and thick, are relatively rare. They are markedly different than sea ice, which is typically less than a few metres thick and survives up to several years. Canada has the most extensive ice shelves in the Arctic along the northern coast of Ellesmere Island. These floating ice masses are typically 40 metres thick (equivalent to a 10-storey building), but can be as much as 100 metres thick. They thickened over time via snow and sea ice accumulation, along with glacier inflow in certain places, and are thought to have been in place over most of the past several thousand years .
Mueller and Copland’s research into ice shelf changes is funded by the Natural Sciences and Engineering Research Council of Canada and ArcticNet. Natural Resources Canada’s Polar Continental Shelf Program provided logistical support for the research conducted in the Canadian Arctic.
The degradation of the Serson Ice Shelf was noted by the Canadian Ice Service, Environment Canada at the beginning of August (http://www.ec.gc.ca/glaces-ice/). CIS provided imagery that was important for the delineation of the current ice extent.
The Ellesmere Island ice shelves are known to harbour unique microbial life, which are particularly vulnerable to the impacts of climate change.
Professor Warwick Vincent, director of the Centre for Northern Studies at Laval University, has studied these organisms since 1998. His team is based each summer at Ward Hunt Island in Quttinirpaaq National Park to monitor the ecological shift from ice-dependent to open water ecosystems.
Professor John England, an NSERC Northern Chair at the University of Alberta, has inferred that the ice shelves have been in place for up to 5,500 years from examining driftwood and other materials that he found behind them.
The Serson Ice Shelf is named after Harold Serson (1926-1992) a scientist with the Defence Research Board who contributed to the study of ice shelves and related phenomena along the northern coast of Ellesmere Island.
Images and maps are available at: