Ward Hunt Ice Shelf
Encyclopedia
The Ward Hunt Ice Shelf is the largest ice shelf
in the Arctic
, located on the north coast of Ellesmere Island
, Nunavut
, Canada
. During the 20th century the Ellesmere Ice Shelf
broke up into six separate shelves, the largest being Ward Hunt. Ward Hunt Ice Shelf is about 155 square miles (401.4 km²) in size, and has been in place for approximately 3,000 years as part of a continuous ice shelf that encompasses the northern coast of Ellesmere Island until the beginning of the twentieth century. In 2005 one of the other shelves, the 25 square miles (64.7 km²) Ayles Ice Shelf
, calved completely.
The Ellesmere ice shelf was documented by the British Arctic Expedition
of 1875-76, in which Lieutenant Pelham Aldrich
's party went from Cape Sheridan
(82.47°N, 61.50°W) west to Cape Alert (82.27°N, 85.55°W), including the Ward Hunt Ice Shelf.
The Ward Hunt ice sheet began breaking up approximately 100 years ago, but was believed to have stabilized by the early 1980s. However, in April 2000, satellite images revealed that a large crack in the ice had begun to form, and in 2003, it was announced that the ice sheet had split completely in two in 2002, releasing a huge pool of fresh water from the largest epishelf lake in the Northern Hemisphere, located in Disraeli Fjord. In April 2008, it was discovered that the shelf was fractured into dozens of deep, multi-faceted cracks. In late July 2008, it was announced that nearly 8 square miles (20.7 km²) broke away from the shelf. In August 2010, another 50 km² (19 sq mi) calved off from the northeast quarter of the ice shelf.
The icebergs released by the breakup now pose a potential danger to shipping and offshore development in the region. Loss of microbial ecosystems caused by the release of the freshwater may also have far-ranging ecological impacts.
The breakup of the Ward Hunt Ice Shelf is tied to steady and dramatic increases in the average temperature of the region over the past decades, correlated with global warming
.
Ice shelf
An ice shelf is a thick, floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface. Ice shelves are only found in Antarctica, Greenland and Canada. The boundary between the floating ice shelf and the grounded ice that feeds it is called...
in the Arctic
Arctic
The Arctic is a region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, the United States, Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost...
, located on the north coast of Ellesmere Island
Ellesmere Island
Ellesmere Island is part of the Qikiqtaaluk Region of the Canadian territory of Nunavut. Lying within the Canadian Arctic Archipelago, it is considered part of the Queen Elizabeth Islands, with Cape Columbia being the most northerly point of land in Canada...
, Nunavut
Nunavut
Nunavut is the largest and newest federal territory of Canada; it was separated officially from the Northwest Territories on April 1, 1999, via the Nunavut Act and the Nunavut Land Claims Agreement Act, though the actual boundaries had been established in 1993...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. During the 20th century the Ellesmere Ice Shelf
Ellesmere Ice Shelf
The former Ellesmere Ice Shelf was the largest ice shelf in the Arctic, encompassing about of the north coast of Ellesmere Island, Nunavut, Canada. The ice shelf was first documented by the British Arctic Expedition of 1875-76, in which Lieutenant Pelham Aldrich's party went from Cape Sheridan ...
broke up into six separate shelves, the largest being Ward Hunt. Ward Hunt Ice Shelf is about 155 square miles (401.4 km²) in size, and has been in place for approximately 3,000 years as part of a continuous ice shelf that encompasses the northern coast of Ellesmere Island until the beginning of the twentieth century. In 2005 one of the other shelves, the 25 square miles (64.7 km²) Ayles Ice Shelf
Ayles Ice Shelf
The Ayles Ice Shelf was one of six major ice shelves in Canada, all located on the northern coast of Ellesmere Island, Nunavut. The ice shelf broke off from the coast on August 13, 2005, forming a giant ice island thick and measuring around by in size . The oldest ice in the ice shelf is...
, calved completely.
The Ellesmere ice shelf was documented by the British Arctic Expedition
British Arctic Expedition
The British Arctic Expedition of 1875-1876, led by Sir George Strong Nares, was sent by the British Admiralty to attempt to reach the North Pole via Smith Sound. Two ships, HMS Alert and HMS Discovery , sailed from Portsmouth on 29 May 1875...
of 1875-76, in which Lieutenant Pelham Aldrich
Pelham Aldrich
Pelham Aldrich CVO was a Royal Navy officer and explorer, who became Admiral Superintendent of Portsmouth Docks.-Biography:...
's party went from Cape Sheridan
Cape Sheridan
Cape Sheridan is on the northeastern coast of Ellesmere Island, Canada situated on the Lincoln Sea in the Arctic Ocean, on the mouth of Sheridan River, west bank...
(82.47°N, 61.50°W) west to Cape Alert (82.27°N, 85.55°W), including the Ward Hunt Ice Shelf.
The Ward Hunt ice sheet began breaking up approximately 100 years ago, but was believed to have stabilized by the early 1980s. However, in April 2000, satellite images revealed that a large crack in the ice had begun to form, and in 2003, it was announced that the ice sheet had split completely in two in 2002, releasing a huge pool of fresh water from the largest epishelf lake in the Northern Hemisphere, located in Disraeli Fjord. In April 2008, it was discovered that the shelf was fractured into dozens of deep, multi-faceted cracks. In late July 2008, it was announced that nearly 8 square miles (20.7 km²) broke away from the shelf. In August 2010, another 50 km² (19 sq mi) calved off from the northeast quarter of the ice shelf.
The icebergs released by the breakup now pose a potential danger to shipping and offshore development in the region. Loss of microbial ecosystems caused by the release of the freshwater may also have far-ranging ecological impacts.
The breakup of the Ward Hunt Ice Shelf is tied to steady and dramatic increases in the average temperature of the region over the past decades, correlated with global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
.
External links
- Ward Hunt Ice Shelf, Environment Canada
- http://earthobservatory.nasa.gov/Study/wardhunt/
- http://www.nasa.gov/missions/earth/f_iceshelf.html
- http://www.commondreams.org/headlines03/0924-06.htm