Ward Hunt Ice Shelf

{{Short description|Ice shelf in the Arctic Ocean}}

{{Use mdy dates|date=October 2022}}

File:Ward Hunt Island, Ice Shelf 06.jpg, Ward Hunt Ice Shelf and Cape Columbia, Ellesmere Island, Canada. View towards east.]]

File:Ward Hunt Island, Ice Shelf 05.jpg

The Ward Hunt Ice Shelf is the largest ice shelf in the Arctic, located near Ward Hunt Island, 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 currently about {{cvt|400|km2}} in size, and has been in place for approximately 4,000 years{{Cite journal|last1=Antoniades|first1=D.|last2=Francus|first2=P.|last3=Pienitz|first3=R.|last4=St-Onge|first4=G.|last5=Vincent|first5=W. F.|date=November 22, 2011|title=Holocene dynamics of the Arctic's largest ice shelf|journal=Proceedings of the National Academy of Sciences|language=en|volume=108|issue=47|pages=18899–18904|doi=10.1073/pnas.1106378108|issn=0027-8424|pmc=3223438|pmid=22025693|doi-access=free}} as part of a continuous ice shelf that encompassed the northern coast of Ellesmere Island until the beginning of the twentieth century. In 2005 one of the other shelves, the {{cvt|25|sqmi|order=flip}} 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.Jeffries, Martin O. [http://pubs.aina.ucalgary.ca/arctic/Arctic39-1-15.pdf Ice Island Calvings and Ice Shelf Changes, Milne Ice Shelf and Ayles Ice Shelf, Ellesmere Island, N.W.T.]. Arctic 39 (1) (March 1986) Reports from Robert Peary's expedition in 1906 described a “broad glacial fringe” covering much of the coast of northwestern Ellesmere Island.{{Cite book|last=Peary|first=Robert E.|title=Nearest the Pole; a narrative of the Polar expedition of the Peary Arctic club in the S.S. Roosevelt, 1905–1906, by R.E. Peary, U.S.N. With ninety-five photographs by the author, two maps and a frontispiece in colour by Albert Operti.|date=1907|publisher=Doubleday, Page & Co.|location=New York|doi=10.5962/bhl.title.6868|url=https://www.biodiversitylibrary.org/item/29932}}

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.{{cite web|url=http://earthobservatory.nasa.gov/Features/wardhunt/|title=Breakup of the Ward Hunt Ice Shelf|author=Michon Scott|date=January 20, 2004|publisher=Earth Observatory, NASA Goddard Space Flight Center|accessdate=December 30, 2011}} In April 2008, it was discovered that the shelf was fractured into dozens of deep, multi-faceted cracks.{{cite news|url=https://www.thestar.com/News/Canada/article/413838 |title=Cracks in Arctic ice shelf signal its demise |author=Bob Weber, The Canadian Press | work=The Star | location=Toronto | date=April 12, 2008 | accessdate=May 27, 2010}} In late July 2008, it was announced that nearly {{cvt|8|sqmi|order=flip}} broke away from the shelf.{{cite web |url=https://www.reuters.com/article/scienceNews/idUSN2931485920080729?sp=true |title= Giant chunks break off Canadian ice shelf |accessdate=July 29, 2008 |author=David Ljunggren |date=July 29, 2008|publisher=Reuters}} In August 2010, another {{cvt|50|km2}} calved off from the northeast quarter of the ice shelf.{{cite web|url=http://visibleearth.nasa.gov/view.php/id=45463|archive-url=https://web.archive.org/web/20150210011438/http://visibleearth.nasa.gov/view.php/id=45463|url-status=dead|archive-date=February 10, 2015|title=Break-up on the Ward Hunt Ice Shelf|date=August 18, 2010|author=NASA Visible Earth|accessdate=February 9, 2015}}

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.{{cite web|url=http://www.weather.com/outlook/weather-news/news/articles/canadian-arctic-nearly-loses-entire-ice-shelf_2011-09-30|title=Canadian Arctic Nearly Loses Entire Ice Shelf|date=September 30, 2011|author=The Associated Press|publisher=The Weather Channel|accessdate=September 30, 2011}}

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 centuries, correlated with long term global warming resulting from the ongoing warming since the last ice age ended at the start of the Holocene period.{{cite web|url=http://news.bbc.co.uk/2/hi/science/nature/3132074.stm|title=Arctic ice shelf splits |date=September 23, 2003|publisher=BBC News|accessdate=December 30, 2011}}{{cite web|url=http://www.nrdc.org/globalwarming/qthinice.asp|title=Global Warming Puts the Arctic on Thin Ice|publisher=Natural Resources Defense Council|accessdate=December 30, 2011}}

Al Gore mentions the Ward Hunt Ice Shelf in his 2007 documentary An Inconvenient Truth.