• Based on expedition reports of polar explorer Robert Peary from 1906 the historical ‘Ellesmere Ice Shelf’ is believed to have extended 500 km along the northern coast of Ellesmere Island. A floating platform of ice secured fast to land and up to 100 meters thick, the ice shelf was formed by the steady accumulation of sea-ice, snow and glacier input between 3000 and 4500 years ago. It was the dominant feature of the coast until the early 1900’s when it began to break up. (Map: Andrew Hamilton (2008))

For the past 3,000 years, a massive floating platform of ice has fringed the northern coast of Ellesmere Island. Formed by the steady accumulation of sea ice, snow and glacier ice over millennia, the Ellesmere Ice Shelf was approximately 100 metres thick and extended 500 kilometres along the coast. At the turn of the 20th century, this landfast mass of ice added an estimated 8,900 square kilometres of real estate to the northern shore of Ellesmere Island, an area larger than Banff National Park.

During the past hundred years, more than 90 percent of the Ellesmere Ice Shelf has collapsed. By the year 2000, only six segments remained: the Serson, Petersen, Milne, Ayles, Ward Hunt and Markham shelves, totalling less than 900 square kilometres. After the collapse of the Markham Ice Shelf in September, only four remain. They are the last ice shelves in North America.

A diagram showing the formation of the epishelf lake in Disraeli Fiord behind the Ward Hunt Ice Shelf. The ice shelf dams freshwater runoff from surrounding glaciers in the fiord. The freshwater is less dense than the seawater and floats on top. With sufficient runoff the layer of freshwater can build up to a depth equal to the thickness of the ice shelf. A crack that formed in the Ward Hunt Ice Shelf effectively broke the ice shelf dam and resulted in the drainage of the epishelf lake. (Map: Derek Mueller (2003)) Ward Hunt cracks
The Ward Hunt Ice Shelf, at 10 kilometres thick, was the largest of Ellesmere’s shelves. In April 2002, it suffered a crack 50 kilometres long and 10 kilometres wide, running from the southern edge of the shelf to the northern edge. The split compromised the structural integrity of the shelf and allowed its dammed meltwater — the largest epishelf lake in the Arctic — to drain into the Arctic Ocean. Its three billion cubic metres of water was equivalent to the amount that flows over Niagara Falls in one week. 

The Ayles Ice Island
In August 2005, the Ayles Ice Shelf made worldwide headlines when it completely calved away from the coast and drifted south with the ocean current, creating the Ayles Ice Island. Approximately 16 kilometres long and five kilometres wide, it was the size of Manhattan and weighed an estimated two billion tonnes. A seismometer at Canadian Forces Station Alert, 260 kilometres to the east, recorded tremors of the calving. But for the magnitude of the break, it all happened surprisingly quickly. A series of satellite images revealed that the loss of the ice shelf lasted no more than two hours.

Petersen crumbles
The Petersen Ice Shelf, south of Ayles, was also crumbling. The shelf edge had receded each summer since 2005 and by 2008 had lost one third of its area. At the same time, hundreds of square kilometers of 50- to 70-year-old landfast sea ice had broken away from the coast, exposing the shelves to further erosion.

The Ward Hunt Ice Shelf break-up in July 2008 animated using cloud-free MODIS images. The animation shows an area that is approximately 75 km wide. (Credit: MODIS image from the Rapid Response Project at NASA/GSFC.Animation courtesy Derek Mueller, Trent University.)

Ward Hunt calves
In April 2008 a large network of fresh cracks was discovered riddling the Ward Hunt Ice Shelf, a sign of further weakening. On July 22 and 23 two ice islands, totalling 20 square kilometers, calved from the Ward Hunt Ice Shelf and drifted into the Arctic Ocean. Over the following weeks, the eastern half of the shelf continued to disintegrate, and by the end of August, an estimated total of 42 square kilometres had been lost.

The Serson Ice Shelf break-up animated using cloud-free MODIS images. The animation shows an area that is approximately 80 km wide. (Credit: MODIS image from the Rapid Response Project at NASA/GSFC. Animation courtesy Derek Mueller, Trent University)

The Markham Ice Shelf break-up animated using cloud-free MODIS images. The animation shows an area that is approximately 40 km wide. (Map: : MODIS image from the Rapid Response Project at NASA/GSFC. Animation courtesy Derek Mueller, Trent University.)

Serson and Markham
In the first week of August 2008, the beautiful rolling hills of the Serson Ice Shelf must have trembled like an earthquake had hit. Two huge sections totalling 122 square kilometres, more than half of the shelf, detached from the coast. A meltwater lake previously dammed by the shelf was likely lost in the breakup, another rare ecosystem washed away.

But the collapse didn’t end there. To the east of the Ward Hunt Ice Shelf, tucked away in a narrow fiord, was the Markham Ice Shelf. A satellite image from July 28 shows the 50-square-kilometre Markham Ice Shelf nestled in the same spot it had likely resided for thousands of years. A satellite image taken two weeks later, on Aug. 12, showed nothing but open water. Sometime in the first two weeks of August the Markham Ice Shelf was lost, having calved completely from the coast and drifted away in the current.

A visible satellite image outlining the six ice shelves of northern Ellesmere Island prior to August 2005 when the Ayles Ice Shelf calved from the coast. Although not visible in at this resolution, the ice shelves, with smooth rolling surfaces and up to 40 meters thick, are very distinct from the surrounding land-fast multi-year sea ice, which is rough and only a few meters thick. (Credit: MODIS Satellite image courtesy of NASA (2003))

Map of Ellesmere Island ice shelves at the end of August 2008. Ice shelves are outlined in black. Left to Right: Serson, Petersen, Milne and Ward Hunt. Quttinirpaaq National Park outlined in green.
CREDIT: MODIS image from NASA. Map courtesy of Derek Mueller

Time-series of the Ayles Ice Shelf collapse on August 13, 2005. The red arrow indicates the location of the calving event that resulted in the formation of the 66 square kilometre Ayles Ice Island.
CREDIT: MODIS satellite images courtesy of NASA, modified by Derek Mueller

Radarsat-1 image of the Ward Hunt Ice Shelf showing the network of cracks threatening the integrity of the ice shelf. The blue line outlines the extent of the ice shelf. The yellow lines trace the extent of previous cracks observed in 2002. The red lines indicate the network of new cracks that were discovered in 2008 and mapped by the Canadian Rangers.
CREDIT: Image courtesy of the Canadian Space Agency, modified by Derek Mueller.

A FORMOSAT-2 image of the eastern Ward Hunt Ice Shelf (2006 extent outlined in red) on July 17, 2008. Note the piece of ice shelf and multiyear landfast ice detached off to the north of Ward Hunt Island.
CREDIT: Image courtesy of Pax Arctica and the Planet Action Initiative, © NSPO 2008 - National Space Organization, Taiwan, Distribution Spot Image S.A., France, All rights reserved.

A FORMOSAT-2 image of the eastern Ward Hunt Ice Shelf (2006 extent outlined in red) on August 18, 2008. Note the new east-west cracks to the south of Ward Hunt Island and further loss at both the northern and southern calving fronts. New snow covers the ice shelf and some sea ice can be seen stuck to the northern edge of the ice shelf.
CREDIT: Image courtesy of Pax Arctica and the Planet Action Initiative, © NSPO 2008 - National Space Organization, Taiwan, Distribution Spot Image S.A., France, All rights reserved.

Radarsat-1 image of the Petersen Ice Shelf showing the progressive loss of 1/3 of its area in the past 3 years. Blue line indicates the extent of the ice shelf from the 1940s to August 2005. Yellow line indicates the extent of the ice shelf between autumn 2005 and 2007. Red line indicates the current extent of the ice shelf as of April 2008.
CREDIT: Canadian Space Agency

A map of the Serson Ice Shelf (2006 extent outlined in red) before it began to break-up in July based on RADARSAT-1 fine beam imagery from February 2008. The Serson Ice Shelf is composed of two sections, one comprised of glacier ice flowing off of Ellesmere Island and another section composed of ancient sea ice and snow that have accumulated over thousands of years. The ice shelf is estimated at 40 m thick and is fringed by thinner multiyear sea ice that helped protect it from the pack ice of the Arctic Ocean.
CREDIT: RADARSAT-1 image copyright Canadian Space Agency. Map courtesy Derek Mueller.

A MODIS image of the Serson Ice Shelf (2006 extent outlined in red) July 28, 2008 prior to its break-up in 2008.
CREDIT: MODIS image NASA. Map courtesy Derek Mueller.

A MODIS image of the Serson Ice Shelf (2006 extent outlined in red) on August 6, 2008.
CREDIT: MODIS image from NASA. Map courtesy Derek Mueller.

A MODIS image of the Markham Ice Shelf (2006 extent outlined in red) on July 28, 2008 prior to calving. Note the open water in Markham Fiord south of the ice shelf.
CREDIT: MODIS image from NASA. Map courtesy Derek Mueller.

A MODIS image of Markham Fiord on August 12, 2008 following the loss of the Markham Ice Shelf (2006 extent outlined in red).
CREDIT: MODIS image from NASA. Map courtesy Derek Mueller.

Operation Nunalivut 2008
Because they exist in remote, extreme conditions, relatively little is known about these shelves. The scientists of the Ellesmere Ice Shelves, Ecosystems and Climate Change Project, a research expedition team, have tried to fill in some of the blanks. In April 2008, members of the project, including polar scientist Derek Mueller, glaciologist Luke Copland, and molecular ecologist Andrew Hamilton travelled with the Canadian Rangers on a two-week sovereignty operation to explore the remaining ice shelves on Ellesmere Island. “We could not have been more fortunate,” says Hamilton. “We were actually able to traverse all these ice shelves and collect valuable data at a critical time.”

Hamilton had never travelled to the ice shelves before. “It wasn’t until actually being there and driving across these ice shelves and the incredible rolling hills that I really understood how unique and different ice shelves are from the surrounding sea ice,” he says. “It feels solid and that’s what makes it more incredible — these massive, massive pieces of ancient ice that we drove on a few months ago are gone now, they’re floating in the Arctic Ocean.”