India An estimated 1.5 to 2 billion people in Asia (Himalayan region) and in Europe (The Alps) and the Americas (Andes and Rocky Mountains) depend on river systems with glaciers inside their catchment areas. Most of the world’s mountain (alpine) glaciers have been retreating since about 1850. These observations surprised climatologists, forcing them to revise their earlier view that glaciers as large as the Antarctic and Greenland ice sheets will respond to climate changes only over 1,000 years or more. On the eve of a European Commission Green Paper released June 26 (“Adapting to Climate Change in Europe—Options for EU Action”) EC President José Manuel Barroso visited the Greenland glacier of Sermeq Kujalleq in Ilulissat. As glaciers retreat, they leave behind deposits of rocks. In general, accumulation has increased over glaciers and ice sheets worldwide in recent decades, including the interiors of Antarctica and Greenland. Instead, glacial retreat refers to the melting away of a glacial. Glacier Retreat Introduction. Forero, Juan. Glaciers in the Alps have lost more than 20 percent of their area since the mid-19th century. It has been estimated that there were approximately 150 glaciers present in 1850, around the end of the Little Ice Age and most glaciers were still present in 1910 when the park was established. The world’s glaciers are in retreat. The mass of a glacier is the amount of ice it contains; mass is added by accumulating snowfall and lost by evaporation and melting. All glacial water eventually finds its way to the sea. Retreat of the Glaciers Our glacial deposits are largely the result of the great continental glacial melt event that ended the Pleistocene. A glacier grows wherever snow accumulates faster than it melts. Alpine glaciers have recently accelerated their retreat and large ice-sheet glaciers have been accelerating their flow to the sea along the coasts of Gre… The melting rate for 2005–2006 was four times greater than that for 1980–1999. What happens during a glacial retreat? Major scientific uncertainties linger about the mechanisms and future progress of glacial melting, especially with regard to the ice sheets of Greenland and Antarctica. In January 2008, a group of NASA and university researchers announced that ice loss from Antarctica had increased by 75% since 1996, from about 112 billion metric tons of ice per year to about 196 bil-. The great abundance of water on the surface of Earth includes a great quantity of ice in the Polar Regions and high…, An iceberg is a large mass of free-floating ice that has broken away from a glacier. “Meltdown in the Mountains.” http://www.unep.org/Documents.Multilingual/Default.asp?DocumentID=530&ArticleID=5760 (accessed May 2, 2008). This has technically been going on since the industrial revolution, but as emissions have continued to increase the issue has only become increasingly exacerbated. ." grown even more than accumulation. Ancient sea levels have risen and fallen many yards/meters during glacial and interglacial (warmer) periods as Earth’s water was alternately locked up in glaciers and returned to the sea as meltwater. Then, copy and paste the text into your bibliography or works cited list. MARQUAND, ROBERT. Sengupta, Somini. Sensitive satellite measurements of the altitude and gravitational attraction of the ice dome on Greenland have revealed that some of the largest glaciers funneling ice from the heartland to the sea more than doubled in speed in the early 2000s. The great tongues of ice high in the Himalayas, the Andes, the Alps and the Rockies are going back uphill at ever greater speeds, according to new research. The glacier flows back to its origin. Glacial Retreat: The majority of the world's glaciers are in retreat. These all depend on glacier-melt, and in the longer term and to some extent so does the level of the oceans. Howat, Ian M. “Rapid Changes in Ice Discharge from Greenland Outlet Glaciers.” Science 315 (2007): 1559–1561. Still, as a result of all the broader climate change effects, glaciers are rapidly melting with huge chunks falling off into the sea, while elsewhere the ice begins to retreat to land. Environmental Science: In Context. These accelerations were partly due to the lubricating effect of water from melting surface ice, but a complete understanding of the acceleration of Greenland’s glaciers was not yet available in 2008. Data going back to 1700 show that glacier tongues were stable until about 1850, and then began to shorten steadily in the European Alps, North America, Asia, and the Southern Hemisphere. New York: Cambridge University Press, 2007. The Athabasca Glacier is not alone in its retreat: Since 1960, glaciers around the world have lost an estimated 8,000 cubic kilometers (1,900 cubic miles) of ice. Pick a style below, and copy the text for your bibliography. At their terminal ends, glaciers may either melt directly, as most alpine glaciers do, or break up into icebergs that float off on the ocean. The retreat of glaciers since 1850 affects the availability of fresh water for irrigation and domestic use, mountain recreation, animals and plants that depend on glacier-melt, and, in the longer term, the level of the oceans. These all depend on glacier-melt, and in the longer term and to some extent so does the level of the oceans. However, a shortage of data on glacier-fed river flow makes it difficult to predict the timing and magnitude of such events. While the thickness changes have fluctuated, losses of more than 1 meter of thickness have occurred in the past 15 to 20 years. See Also Antarctic Issues and Challenges; Climate Change; Glaciation; Global Warming, Solomon, S., et al, eds. This situation is particularly acute for irrigation in South America, where numerous artificial lakes are filled almost exclusively by glacial melt. The resulting body of ice is…, Glacier The retreating glacial ice never actually flows backwards; the ice simply melts away faster than is replenished from new glacial ice formation in the zone of accumulation. Therefore, that information is unavailable for most Encyclopedia.com content. “At this rate, by 2100 about 80 percent of the surface of the glacier will be gone,” says Ralph Logon, a Swiss geo-morphologist and expert on glaciers. The recent substantial retreat and an acceleration of the rate of retreat since 1995 of a number of key outlet glaciers of the Greenland and West Antarctic ice sheets foreshadow a rise in sea level,having a potentially dramatic effect on coastal regions worldwide. A retreating glacier loses more water than it gains and so causes sea level to rise. Its retreat is visible in this photo, where the glacier’s front edge looms several meters behind the tombstone-like marker that indicates the edge of the ice in 1992. ABLATION (GLACIAL): The erosive reduction of ice or snow from the surface of a mass of ice. In areas where the glaciers are melting, river runoff will increase for a period before a sharp decline in runoff. Glaciers in alpine areas act as buffers. Barroso says that the EC will push, at a UN climate summit in Bali this December, for a new treaty to replace the Kyoto Protocol, which ends in 2012. This is also occurring in tropical glacier summits such as Mount Kilimanjaro in Africa, and Chacaltaya Glacier in Bolivia which are showing some of the largest proportionate glacial loss. In early 2008, scientists with the United Nations Environment Programme announced that mountain glaciers were melting faster than ever as a result of global climate change. Landslides falling into glacial lakes may cause tsunamis and river floods and thus pose hazard to … Together, evaporation and melting are termed ablation. 16 Oct. 2020 . © 2019 Encyclopedia.com | All rights reserved. Complete melting of the Greenland and West Antarctic ice sheets would raise global sea level between 16 and 33 ft (5 and 10 m), with massive consequences for coastal and island ecosystems and for many human settlements. Current glacier retreat is a challenge for glacier monitoring in three ways: First, the rapid glacier retreat with disintegration of large glaciers into smaller ones, the formation of periglacial lakes, and the increased debris cover makes it difficult to keep up length change and mass balance measurements. Glaciation is the accumulation of ice in a given area when more snow falls in winter than melts in summer. © 2020 Global Greenhouse Warming. https://www.encyclopedia.com/environment/energy-government-and-defense-magazines/glacial-retreat, "Glacial Retreat In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. All Rights Reserved. The Little Ice Age was a period from about 1550 to 1850 when the world experienced relatively cool temperatures compared to the present. Without the water from mountain glaciers, serious problems are inevitable and the UN’s Millennium Development Goals for fighting poverty and improving access to clean water will be jeopardized” United Nations Environment Programme, 2007 Global Outlook for Ice and Snow. In it place it leaves morraines. Within 40 years the effects of climate change could mean a need to “increase the height of dikes, [relocate] ports, industry, and entire cities and villages from low-lying coastal areas….”. Mr. Logon notes that while glacial melting is a long-term concern, it does not receive the same attention in Swiss cantonal politics as immediate problems of floods, avalanches, and other crises. The problem is not simply that the Aletsch is melting, scientists say. During the rainy season, water is stored in the glaciers and the melt water helps maintain river systems during dry periods. Glacier Bay today is the product of the Little Ice Age, a geologically recent glacial advance in northern regions. Environmental Science: In Context. Glaciology is the study of ice and its effects. Every other continent is warming, and the Arctic is warming fastest of anywhere on earth." (Glaciers are flowing masses of ice, created by years of snowfal…, Gjellerup, Karl (2 June 1857 - 11 October 1919), Intergovernmental Panel on Climate Change, https://www.encyclopedia.com/environment/energy-government-and-defense-magazines/glacial-retreat. These, too, eventually melt. If the fast-paced melting continues, the. First, melting of glacial ice raises sea level by increasing the amount of water in the oceans. eval(ez_write_tag([[336,280],'global_greenhouse_warming_com-box-4','ezslot_6',263,'0','0']));Central Asian countries have also been historically dependent on the seasonal glacier melt water for irrigation and drinking supplies. In March 2008, the World Glacier Monitoring Service of the United Nations announced that the world’s alpine glaciers were melting faster than ever. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates. MASS BALANCE (GLACIAL): The difference between the accumulation and ablation (reduction) of ice mass over a period of time. Alpine glaciers have recently accelerated their retreat and large ice-sheet glaciers have been accelerating their flow to the sea along the coasts of Greenland and the West Antarctic Peninsula. Materials deposited by a glacier as it retreats are called ground moraines. Glacial retreat is the recession of a glacier. B. Shrestha, Hydrologist-Engineers, Snow and Glaciers Hydrology Unit, Department of Hydrology and Meteorology (DHM)/Ministry of Science and Technology, Kathmandu Nepal. The glacier is in rapid retreat, which is a fact and a clear sign of climate change,” Mr. Albrecht says. In areas that are heavily dependent on water runoff from glaciers that melt during the warmer summer months, a continuation of the current retreat will eventually deplete the glacial ice and substantially reduce or eliminate runoff. A glacier is a mass of ice larger than 247 acres (one tenth of a square kilometer) that starts on land, but can move out over co…, Ice is the solid state of water . A glacier grows wherever snow accumulates faster than it melts. Zealand and western Scandinavia (a small fraction of the global whole) advanced in the late 1990s. Since ice can appear on or in the earth as well as in its seas and other bodies of water and…, Introduction a. Disappearance of many alpine glaciers in the Andes and Himalayas could be disastrous for these persons. If ablation is greater than accumulation, the glacier thins and eventually retreats (shortens). Large temporary lakes of glacial meltwater may rupture, causing catastrophic floods and even shifting global climate by dumping freshwater into the oceans and so altering their circulation. c. The glacier ceases to flow. GLACIAL RETREAT 1 KENAI FJORDS NATIONAL PARK: L a n d s a t P h o t o – D r y V a l l e y K.F.N.P is located on the southeastern portion of Alaska’s Kenai (pronounced: Key-nigh) Peninsula, bordering the Gulf of Alaska. Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Studies show that human-caused global warming is the leading cause of glacier retreat. “Greenland is of major significance to the rest of the world in our struggle to halt climate change,” Mr. Barroso told reporters afterward. . The commission’s report argues for dramatic prevention measures to combat the effects of a temperature rise. In particular, the rate of retreat of 30 closely observed “reference glaciers” around the world had doubled from 2004–2005 to 2005–2006. glacier could lose about 80% of its surface by 2100. Encyclopedia.com. The director of the group, according to a press release from the United Nations Environment Programme (UNEP), said that the latest figures were “part of what appears to be an accelerating trend with no apparent end in sight.” Several glaciers in the Himalayas and elsewhere could disappear completely within a few decades, if current melting trends continue.