Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA). ." 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. The glaciers of the Cordillera Blanca mountain range in the Andes to the north of the Peruvian capital Lima have been in steady retreat for several decades but in … Glacial retreat: “With few exceptions, all the alpine glaciers of the world are losing mass and it is predicted that this trend will continue as global warming progresses. 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. Most is located in the ice sheets of Antarctica (91%) and Greenland (7.9%). Mass loss from Greenland and Antarctica has also accelerated. Glacial retreat is a misnomer as glaciers never really move in reverse. Also, over a billion people depend on meltwater from alpine glaciers for year-round drinking water supplies. But the overall figure is one of shrinkage. Glacial retreat slowed and even reversed, in many cases, between 1950 and 1980 as a slight global cooling occurred. These all depend on glacier-melt, and in the longer term and to some extent so does the level of the oceans. Pick a style below, and copy the text for your bibliography. UN scientists warned that people who depend on glacial meltwaters for clean water might be seriously affected by the disappearance of glaciers within a few decades; for example, in India about 750 million people depend on glacial melt from the Himalayas. Mid-latitude mountain ranges such as the Himalayas, Alps, Rocky Mountains, Cascade Range, Glacier National Park, and the southern Andes. The potential for major sea level rise depends mostly on a significant melting of the polar ice caps of Greenland and Antarctica, as this is where the vast majority of glacial ice is located. Glaciers are large masses of ice that flow slowly downhill. 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 . 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. 16 Oct. 2020 . Last year, it lost 115 meters—though in 2004 and 2005, the glacier gained about 50 meters per year. It was a massive retreat of a … “Extracting a Climate Signal from 169 Glacier Records.” Science 308 (2005): 675–677. A retreating glacier loses more water than it gains and so causes sea level to rise. Glacial retreat is the recession of a glacier. Landslides falling into glacial lakes may cause tsunamis and river floods and thus pose hazard to … 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. Retreat of the Glaciers Our glacial deposits are largely the result of the great continental glacial melt event that ended the Pleistocene. Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Exceptionally, some glaciers in New. Natural hazards are a prominent issue due to the large population within the Alps, and settlements are at risk of floods, avalanches, and landslides related to glacial melting and retreat. The Little Ice Age was a period from about 1550 to 1850 when the world experienced relatively cool temperatures compared to the present. 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. Oerlemans, J. "Glacial Retreat It retreats—that is, its terminal edge, the end of the glacial tongue, ends at progressively higher elevations—whenever melting exceeds accumulation. National Snow and Ice Data Center (US). Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. See Also Antarctic Issues and Challenges; Climate Change; Glaciation; Global Warming, Solomon, S., et al, eds. Typically, glaciers exist and may even form in areas where: 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. However, a shortage of data on glacier-fed river flow makes it difficult to predict the timing and magnitude of such events. 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. Hundreds of such glaciers feed water to the ocean around the coasts of Greenland and Antarctica, and account for most glacial flow on the planet. Glaciers in alpine areas act as buffers. The continued glacial retreat will have a number of different quantitative impacts. Glacier Bay today is the product of the Little Ice Age, a geologically recent glacial advance in northern regions. Ice sheets eventually get so deep—the average thickness of the Antarctic ice sheet is about 1.3 mi (2.1 km)—that the ice flows slowly under its own weight toward the edges of the landmass. When ice glaciers melt faster, temperatures rise further, and more glaciers shrink, which creates a vicious cycle that is significantly ch… 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. MARQUAND, ROBERT. https://www.encyclopedia.com/environment/energy-government-and-defense-magazines/glacial-retreat, "Glacial Retreat The processes of accumulation and ablation are complex and differ from glacier to glacier, and between alpine glaciers and the ice sheets of Antarctica and Greenland. 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. “Glaciers in Retreat.” New York Times (July 17, 2007). A glacier grows wherever snow accumulates faster than it melts. The retreat—combined with some of the most extensive thinning on the icefield—created new areas of open water in the fjord (dark blue) and exposed rocky fjord walls (brown). These, too, eventually melt. The glacier reduces in size as the ice in the zone of wastage melts. The world's glaciers are retreating at a concerning rate. 1) Glaciers carve fjords in valleys where they travel. “U.N. Then, copy and paste the text into your bibliography or works cited list. Major scientific uncertainties linger about the mechanisms and future progress of glacial melting, especially with regard to the ice sheets of Greenland and Antarctica. A glacier retreats when its terminus does not extend as far downvalley as it previously did. 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. Most online reference entries and articles do not have page numbers. Studied by glaciologists, the coincidence of glacial retreat with the measured increase of atmospheric greenhouse gases is evidence underpinning anthropogenic climate change. First, melting of glacial ice raises sea level by increasing the amount of water in the oceans. 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-. 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. b. Most of the world’s mountain (alpine) glaciers have been retreating since about 1850. This has technically been going on since the industrial revolution, but as emissions have continued to increase the issue has only become increasingly exacerbated. This has resulted in net mass losses for alpine and ice-sheet glaciers. Glacial Retreat: The majority of the world's glaciers are in retreat. The glacier is in rapid retreat, which is a fact and a clear sign of climate change,” Mr. Albrecht says. Disappearance of many alpine glaciers in the Andes and Himalayas could be disastrous for these persons. "Glacial Retreat ." The article acknowledges the consequences of such glaciers melting rapidly if the world’s climate continues to rise. These all depend on glacier-melt, and in the longer term and to some extent so does the level of the oceans. Cite this article Pick a style below, and copy the text for your bibliography. This is because global warming allows air to carry higher humidity, resulting in greater winter snowfall. It retreats—that is, its terminal edge, the end of the glacial tongue, ends at progressively higher elevations—whenever melting exceeds accumulation. Yet the implication of glacier and ice cap melts are being seized, dramatically, by federal Europe. MASS BALANCE (GLACIAL): The difference between the accumulation and ablation (reduction) of ice mass over a period of time. The commission’s report argues for dramatic prevention measures to combat the effects of a temperature rise. Bolivia and Peru may face drinking-water shortages in the near future due to alpine glacial retreat; India and its neighbors, with their much larger populations, face an even larger crisis. The Holocene, starting with abrupt warming 11,700 years ago, resulted in rapid melting of the remaining ice sheets of North America and Europe. If the fast-paced melting continues, the. Although this much melting would probably require several centuries, Greenland and Antarctica melting are each causing sea level to rise about 0.02 in (0.5 mm) per year. In it place it leaves morraines. Environmental Science: In Context. Environmental Science: In Context. While most of Antarctica is remaining cold, rapid increases in summer ice melt, glacier retreat and ice shelf collapses are being observed in Antarctic Peninsula, where the stronger winds passing through Drake Passage are making the climate warm exceptionally quickly. 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. Statistics predict future levels of glacier loss will reach an all-time high. Glacial retreat leaves boulders and masses of scraped-together rocky debris and soil called glacial moraines. Zealand and western Scandinavia (a small fraction of the global whole) advanced in the late 1990s. “I call it the retreat of the glacier,” says Laudo Albrecht, a local director of Pronatura, an environmental group with 100,000 members in Switzerland. In general, accumulation has increased over glaciers and ice sheets worldwide in recent decades, including the interiors of Antarctica and Greenland. 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. Glaciation is the accumulation of ice in a given area when more snow falls in winter than melts in summer. “The ice is melting faster than anybody predicted…. Glacier retreat results in a variety of negative consequences, including increased sea levels, floods, and fresh water shortages. 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. © 2019 Encyclopedia.com | All rights reserved. The Aletsch is the largest glacier in the Alps. Glacial melting has two main impacts on the environment. grown even more than accumulation. Glacially-supplied water resources are vital for energy, agriculture, and other human uses in Switzerland. As glaciers retreat, they leave behind deposits of rocks. “Meltdown in the Mountains.” http://www.unep.org/Documents.Multilingual/Default.asp?DocumentID=530&ArticleID=5760 (accessed May 2, 2008). If ablation is greater than accumulation, the glacier thins and eventually retreats (shortens). Globally, not all glaciers thinned during 2005–2006, but the overall trend was strongly toward accelerated melting. 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. New York: Cambridge University Press, 2007. CONCEPT Antarctica, too, was melting more rapidly in the early 2000s. (October 16, 2020). The report warned that all tropical glaciers, such as those in the Andes Mountains in South America, were likely to disappear in the next 15 years. Therefore, that information is unavailable for most Encyclopedia.com content. a. 19,000 years ago and accelerated after ca. B. Shrestha, Hydrologist-Engineers, Snow and Glaciers Hydrology Unit, Department of Hydrology and Meteorology (DHM)/Ministry of Science and Technology, Kathmandu Nepal. “All About Glaciers.” http://nsidc.org/glaciers/ (accessed May 2, 2008). To meet the challenges of ensuring water security for the populations that depend on these glaciers, the Atlas makes a series of recommendations for policy makers in the region. Sengupta, Somini. Accelerated melting of the glaciers will first afflict downstream populations with increased flooding, then with water shortages as glacier-fed rivers dry up. Climate Change 2007: The Physical Science Basis: Contribution of Working. The retreat accelerated in the late 1990s, and by 2015, three glaciers that fed into HPS-12 from the sides were cut off. Materials deposited by a glacier as it retreats are called ground moraines. The Little Ice Age reached its maximum extent around 1750. However, since 1980 a significant global warming has led to glacier retreat becoming increasingly rapid and ubiquitous, so much so that many glaciers have disappeared and the existence of a great number of the remaining glaciers of the world is threatened. In recent decades, Pine Island Glacier's rapid retreat raised fears that the glacier could "collapse," freeing the ice sheet it buffers to flow even more rapidly into the southern seas. Sea level rose at about 0.13 inches (3.3 mm) per year for 1993–2003, partly as the result of increased ocean volume from glacial melting and partly from the expansion of warming seawater. If accumulation is greater than ablation, the glacier advances (lengthens). “Yes, it should retreat, but not so fast. “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. Together, evaporation and melting are termed ablation. lion, despite increased snow accumulation in the center of the continent. CNN.com. : Glaciers Shrinking at Record Rate.” March 17, 2008. http://www.cnn.com/2008/TECH/03/17/un.climate.ap/index.html?iref=newssearch (accessed May 2, 2008). ICE SHEET: Glacial ice that covers at least 19,500 square mi (50,000 square km) of land and that flows in all directions, covering and obscuring the landscape below it. 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. All Rights Reserved. In particular, the rate of retreat of 30 closely observed “reference glaciers” around the world had doubled from 2004–2005 to 2005–2006. Glaciers are large masses of ice that flow slowly downhill. 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. c. The glacier ceases to flow. Glacier Retreat Introduction. The problem is not simply that the Aletsch is melting, scientists say. Ice-sheet mass loss does not, as in the case of alpine glaciers, take the form of ice turning to water and flowing to the sea; rather, glaciers at the edge of the sheet speed up, dumping more water into the sea in the form of icebergs. A small fraction of this ice, about 0.55%, exists as alpine valley glaciers, ice fields, and the like. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list. Green.TV • 20 October 2015. Yala Glacier, Langtang Valley, Nepal; the lake in the foreground is evidence of glacial retreat, according to the study. In Norway, the Alps, and the Pacific Northwest of North America, glacier runoff is important for hydropower. Glaciers have melted for 2,500 years in Europe; at one ice-age point, the Aletsch nearly covered local mountain peaks. The rate of melting more than doubled from 2004–2005 to 2005–2006 at 30 closely monitored “reference glaciers” around the world. 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….”. ABLATION (GLACIAL): The erosive reduction of ice or snow from the surface of a mass of ice. Most glaciers have been retreating for decades due to climate change, a problem that has been particularly acute in the tropical Andes since the 1950s. Since ice can appear on or in the earth as well as in its seas and other bodies of water and…, Introduction As global warming raises temperatures glaciers are retreating almost everywhere in the world. Forero, Juan. The Holocene glacial retreat is a geographical phenomenon that involved the global deglaciation of glaciers that previously had advanced during the Last Glacial Maximum. The following article recognizes the concern within environmental and scientific communities for the speed at which the Aletsch Glacier, the largest in the Swiss Alps, is melting. 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. This situation is particularly acute for irrigation in South America, where numerous artificial lakes are filled almost exclusively by glacial melt. 50 kilometers of ice [a year]… three times more than the Alps.” Scientists argue that ocean levels could rise seven meters should Greenland’s ice melt entirely. Since then, the massive glacier that filled the bay has retreated 65 miles to the heads of its inlets. (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. However, ablation—mostly in the form of summer melting—has. Ice sheet retreat initiated ca. Credit: ICIMOD/Samjwal Bajracharya Rather, the ice sheets seem to be responding in mere decades. A glacier retreats when more ice melts away during the summer than that which forms during the winter. Introduction it becomes smaller and smaller. 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. During the rainy season, water is stored in the glaciers and the melt water helps maintain river systems during dry periods. Glaciers of less than 100 meters are likely to disappear completely within the next 50 to 100 years, at this rate of change. While the thickness changes have fluctuated, losses of more than 1 meter of thickness have occurred in the past 15 to 20 years. GLACIER: A large mass of ice slowly moving over a landmass, resulting from a multi-year surplus accumulation of snowfall in excess of snowmelt. ." The resulting body of ice is…, Glacier Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites: http://www.chicagomanualofstyle.org/tools_citationguide.html. Higher temperatures and less snowfall have been causing many glaciers around the world to retreat recently. . Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. However, the date of retrieval is often important. As the glaciers retreat, these coastal United Nations Environment Programme. . Glaciology is the study of ice and its effects. Instead, glacial retreat refers to the melting away of a glacial. In the past 30 years, studies show, the Aletsch has been losing 50 meters of length a year and is thinning. Environmental Science: In Context. In 2008, some research showed that dark soot (carbon) particles from burning fuel may be contributing as much to Himalayan glacial melting as global warming forced by greenhouse gases. 15,000 years ago. The melting rate for 2005–2006 was four times greater than that for 1980–1999. Global warming creates temperature increases, causing glaciers to melt faster. 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. A fjord is a long, narrow valley with steep sides carved by glacial movement. What concerns scientists is the pace of the melt. The retreat of mountain glaciers, notably in western North America, Asia, the Alps, Indonesia and Africa, and tropical and subtropical regions of South America, has been used to provide qualitative evidence for the rise in global temperatures since the late 19th century. 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. 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. All glacial water eventually finds its way to the sea. About 75% of the world’s freshwater is in the form of 7.9 million cubic mi (33 million cubic km) of ice. The world’s glaciers are in retreat. 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… There it feeds riverlike glaciers that slide down valleys to the sea. Glaciers in the Alps have lost more than 20 percent of their area since the mid-19th century. glacier could lose about 80% of its surface by 2100. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates. Over 100 million people live no more than 3 ft (1 m) above sea level. The alpine glaciers of the world have been in retreat since the mid-nineteenth century. The retreat—combined with some of the most extensive thinning on the icefield—created new areas of open water in the fjord (dark blue) and exposed rocky fjord walls (brown). Glaciers form at high latitudes and altitudes where vast quantities of fallen snow accumulate over time and compress into thick masses of ice that flow downhill under their own weight. Some years show gains in length, others record losses. Find out why, and why it matters to the world, in … Encyclopedia.com. Encyclopedia.com. 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. In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations.
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