Retreat of the glaciers since 1850

The retreat of the Glacier S since 1850 , world and fast, affects: the access to fresh water for the irrigation and the use domesticates, the leisures of mountain, the animals and the plants which depend on the cast iron of the glaciers, and longer-term, the level of the oceans. Studied by the glaciologist S, the temporal coincidence of the retreat of the glaciers with the increase measured in the atmospheric Gaz to greenhouse effect is often quoted like proof of the Climate warming Anthropique. Mountains with semi-latitude such as the the Himalayas, the the Alps, the Rocky Mountains, the Chain of the Cascades, and the the southernmost Andes, as well as the tropical tops isolated such as the Kilimandjaro in Africa, show proportioned glacial losses which are among more grandes .

The Petit Ice Age is one period between approximately 1550 and 1850 when the world knew relatively fresh temperatures compared with now. Later, until approximately 1940, the glaciers around the world moved back while the climate was heated. The glacial retreat slowed down and was even reversed, in much case, between 1950 and 1980, because light a climatic Refroidissement occurred. However, since 1980, a significant climate warming led to an increasingly fast retreat of the glaciers and in the whole world, so much so that much from glaciers disappeared and than the existence of a great number of other remaining glaciers in the world are threatened. In the areas such as the Andes of the South America and the Himalayas in Asia, the end of the glaciers will have a potential impact on water provisions. The retreat of the glaciers of mountain, in particular in the West of the North America, in Asia, in the Alps, in Indonesia, in Africa, and in tropical and subtropical areas of South America, was used like qualitative proof of the rise in the total temperatures since the end of the 19th siècle . The recent substantial retreat, as well as an acceleration the speed of retreat since 1995 of a certain number of principal glaciers of discharge system of the Greenland and Ice cap of the the Western Antarctic, can announce a rise in the sea level, having a potentially dramatic effect on coastal regions in the whole world.

Glacial weight breakdown

Glaciers of semi-latitude

The glaciers of semi-latitude are located between the tropic of Cancer and the Arctic Cercle, and between the tropic of Capricorn and the Cercle the Antarctic. These two areas support the ice of the glaciers of mountain, of the glaciers of valley as well as smaller icecaps, which are usually located in the highest mountainous regions. All these glaciers are located in assembly lines, in particular the Himalayas, the Alps, the Rocky Mountains and coastal Chaînes of North America, the Andes of Patagonie in South America, and the assembly lines in the island which the New Zealand constitutes. The glaciers, in these latitudes, are extended and tend to being all the more massive as they are located close to the polar regions. These glaciers are those which were most largely studied during the 150 last years. Just as the glaciers located in tropical zone, practically all the glaciers of the semi-latitudes are in a situation of negative weight breakdown and move back.

Europe, Asia, Oceania

The World Security service of the Glaciers returns account, every five years, of the changes of the termini of glaciers, or less raised ends, everywhere in the world. In their edition 1995-2000, they noted the variations of the ending period of the glaciers in all the glaciers of the Alps. During the five years Swiss period of 1995 to 2000,103 of the 110 glaciers examined in , 95 of the 99 glaciers in Austria, 69 glaciers in Italy, and the 6 glaciers in France were in retreat. The French glaciers underwent Nets retreats in the years 1942 to 1953, followed advances until 1980, then again of retreats as from 1982. For example, since 1870, the Glacier of Argentière and the glacier of the Mont Blanc moved back respectively of 1 150 m and of 1 400 Mr. the largest glacier of France, the sea of Ice, 11 km length and 400 m thickness, lost, in 130 years, 8,3% his length, either 1 km, and was thinned, in 130 years, of 27%, or 150 m, in the median section of the glacier. The Glacier of Let us work with Chamonix, in France, moved back of 1 200 m compared to the extensions observed at the beginning of the 20th century. In 2005, out of 91 studied Swiss glaciers, 84 moved back their ending periods of 2004, and the 7 remainders did not show any change.

Other researchers noted that the glaciers through the Alps seemed to move back at a speed faster than a few decades ago. In 2005, out of the 91 glaciers observed, 84 moved back and none advanced. The glacier of Trift had moved back of more than 500 m in only three years, of 2003 to 2005, which accounts for 10% its overall length. The Glacier of Aletsch, the largest glacier of Switzerland, moved back of 2 600 m since 1880. This speed of retreat also increased since 1980, and 30% of the total retreat, are 800 m, occurred in the last 20% moments of the period of time. In the same way, in 1980, among the glaciers of the Italian Alps, a third only was in retreat, whereas since 1999,89% of these glaciers moved back. The researchers found that, of 2004 to 2005, all the glaciers of the Italian Alps moved back. Repeated photographs of the glaciers of the Alps provide clear evidence that the glaciers in this area moved back appreciably during the previous decades. The glacier of Morteratsch, in Switzerland, in is a typical example. Annual measurements of change length started in 1878. The total retreat of 1878 to 1998 is on the whole of 2 km, with an average annual speed of retreat of roughly 17 m/an. This long-term average was clearly exceeded these last years, because the retreat was of 30 m/an of 1999 to 2005. A serious business, which had in the past an enormous impact on the lives and the goods, is a glacial rout which brought died and destruction. The glaciers pile up, at their final end, of the rocks and the ground which were torn off mountainous slopes. These remains piles often form stoppings which maintain water behind them and form glacial lakes as the glaciers found and move back further. These final moraines is often unstable and known to burst when they overflow, or when they are moved by earthquakes, crumblings or avalanches. If a glacier has a fast cast iron cycle during the hottest months, the final moraine can not be enough strong to continue to maintain the lake which is formed behind it, driving with a massive localized flood. The risk increases because of creation and by the expansion of the glacial lakes resulting from the retreat of the glaciers. Floods, in the past, were mortals and had like consequence of enormous property damages. The cities and the villages, in stiff and narrow valleys, which are downstream from the glacial lakes, run the greatest risk. In 1892, a glacial rout released approximately 200 000 m ³ of water of the glacial lake of Russet-red Head, which resulted in the death of 200 people in the French city of Saint Gervais. The glacial routs are known to occur in all the areas of the world where glaciers are. One expects that the continuous retreat of the glaciers creates and increases the glacial lakes, increasing the danger of future routs.

Although the glaciers of the Alps caused more attention on behalf of the glaciologists than those of the other areas of Europe, research indicates that in all the major part of Europe, the glaciers moved back quickly. In the Kebnekaise, mountain in the north of the Sweden, a study of 16 glaciers between 1990 and 2001 found that 14 glaciers moved back, one advanced and one was stable. During the 20th century, the glaciers of Norway moved back, with, however, of short periods of advanced overall around 1910, 1925 and in the years 1990. In years 1990,11 of the 25 Norwegian glaciers observed had advanced, because of precipitations with the top of the normal during several consecutive winters. However, since the years 1990, and especially since 2000, after several consecutive winters where few precipitations took place, and the summers 2002 and 2003 which underwent records of heat, the Norwegian glaciers decreased appreciably. In 2005, only one of the 25 glaciers supervised in Norway advanced, two were stationary and 22 moved back. Since 1999, the Norwegian glacier Engabreen moved back of 179 m, and since 2000, the glaciers Brenndalsbreen and Rembesdalsskåka moved back respectively of 116 m and of 206 Mr. During the only year 2004, the glacier Briksdalsbreen moved back of 96 m, which represents its record of retreat since the year 1900 when one started to supervise it. Generally, of 1999 to 2005, Briksdalsbreen moved back of 176 Mr.

The Himalayas and the other assembly lines of the Central Asia contain great areas with glaciers. These glaciers provide critical supplies water for arid countries such as the Mongolia, the Western China, the Pakistan and the Afghanistan. Just as for the glaciers of the other parts of world, the mass of the glaciers of Asia is declining rapid. The loss of these glaciers is likely to have an enormous impact on the ecosystem of the area.

A report/ratio of WWF concluded that 67% of the glaciers of the Himalayas moved back. By examining 612 glaciers of China between 1950 and 1970,53% of the studied glaciers moved back. After 1990,95% of these glaciers were measured in retreat, indicating that this retreat extended even more. The glaciers of the area of the Mount Everest are all in a situation of retreat. The Glacier of Khumbu, which is the ones of the main roads until the base of the Mount Everest, moved back of 5 km since 1953. The Glacier of Rongbuk, draining the northern face of the Mount Everest to the Tibet, moves back of 20 m per annum. In India, the Glacier of Gangotri, which is a source of significant water water of the Gange, moved back of 34 m per annum between 1970 and 1996, and has an average of loss of 30 m per annum since 2000. With the passing of the glaciers in the Himalayas, a certain number of glacial lakes were created. A concern growing is the glacial potential of rout — the researchers estimate that 20 lake glacial with the Nepal and 24 with the Bhutan constitute risks for the human populations, if the stoppings of final moraines collapse. An identified glacial lake as potentially dangerous is Raphstreng Tsho in Bhutan, which measured 1,6 km length, 0,96 km broad and 80 m of depth in 1986. In 1995, the lake had grown east reached 1,94 km length, 1,13 km broad and 107 m of depth. In 1994, the glacial rout of Luggye Tsho, a glacial lake beside Raphstreng Tsho, killed 23 people downstream.

The glaciers in the chain of Ak-shirak to the Kyrgyzstan underwent, between 1943 and 1977, a light loss of mass, then, between 1977 and 2001, an acceleration leading to a loss of 20% of their remaining mass. In the Tian Shan, that Kyrgyzstan divides with China and the Kazakhstan, the studies, in the northern part of this assembly line, show that the glaciers, which take part in the supply the water of this arid area, lost 2 almost; km ³ of ice per annum between 1955 and 2000. The Université of Oxford also announced that an average of 1,28% of the volume of these glaciers had been lost each year between 1974 and 1990.

In the south of Tien Shan, the assembly line of Pamir, located mainly in the Tadjikistan, has several thousands of glaciers, which all are in a general situation of retreat. During the 20th century, the glaciers of Tadjikistan lost 20 km ³ of ice. The Glacier Fedchenko, which has 43 km length, which is largest of the Tadjikistan as well as the largest nonpolar glacier on the Earth, lost 1,4% its length, that is to say 1 km, 2 km ³ of mass, and its glacial sector was reduced of 11 km ² during the 20th century. In the same way, the glacier close to Skogatch lost 8% of its total mass between 1969 and 1986. Tadjikistan and the adjoining countries of the chain of Pamir strongly depend on the glacial flow to ensure the flow of the rivers during the dry drynesses and seasons which occur each year. Disappearance continues ice of the glaciers will have like consequence a short-term increase in melt water running in the rivers and the torrents, followed by one long-term reduction in this water.

In New Zealand, the glaciers of mountain were in general retreat since 1890, with an acceleration of this retreat since 1920. The majority of the glaciers thinned notably and were reduced in the face, and the zones of snow drift went up in altitude, progressively of the advance of the 20th century. For the period 1971-75, the Ivory glacier moved back of 30 m, and approximately 26% of the surface of the glacier was lost for the same period. Since 1980, many small glacial lakes were created behind the new final moraines of several of these glaciers. The glaciers such as Classen, Godley and Douglas have all maintaining new lakes glacial below their termini, which had with the glacial retreat during the 20 last years. The satellite image indicates that these lakes continue to increase in the face.

Several glaciers, in particular the Glacier Fox and the glaciers of Franz Josef in New Zealand, periodically advanced, particularly during the Nineties, but with small scales, compared with the retreat of the 20th century. These large glaciers, which are located on steep slopes and which overflow quickly, were very reactive with the small changes of weight breakdown. A few years of favorable conditions in advance of the glacier, such as colder snowfalls and temperatures, are quickly transformed into projections, then, when these favorable conditions finish, are followed retreats quite as fast. The glaciers which had advanced in some places of New Zealand, did it because of a provisional change of time related to El Niño, which brought, since 2002, more precipitations and of cloudy and fresh summers.

America

The North-American glaciers are mainly located along the peak of the Rocky Mountains at the United States and Canada, and of the assembly lines of the Pacifique coast extending from the north of the California until in Alaska. While the Greenland is geologically associated with North America, it is also part of the area Arctique. Except some coastal glaciers such as the Glacier of Taku, which are, in a advanced stage of their cycle of coastal glacier, most widespread along the coast of Alaska, practically all the glaciers of North America are in a situation of retreat. The speed observed of retreat increased quickly since approximately 1980, and, since, as a whole, each decade saw moreover high speeds of retreat that the preceding ones. There are also small remainders of dispersed glaciers all along the Sierra Nevada of California and the Nevada.

The Chaîne of the Cascades of Western North America extends from the south of the British Columbia (Canada) until the north of the California. Separately Alaska, approximately half of the glacial zone of the United States is contained in the 700 glaciers (at least) of the North Cascades, of which a part between the Canadian border and the highway Interstate 90 in the center of the state of Washington. These glaciers store as much water than in all the lakes and tanks of the remainder of the state, and provide most of the flow of the torrents and rivers during the dry months of the summer, is roughly 870 000 m ³.

Recently, in 1975, much of glaciers of North Cascades had advanced, because of fresher time and of increased precipitations which occurred of 1944 to 1976. However, in 1987, all the glaciers of North Cascades had moved back, and since the middle of the years 1970, the speed of retreat of the glaciers increased at each decade. Between 1984 and 2005, the glaciers of North Cascades lost on average more 12,5 m thickness and 20% and 40% of their volume.

The glaciologists working on the glaciers of North Cascades note that, since 1985, the 47 supervised glaciers move back and that four of them — the glacier of Spider, the glacier of Lewis (image opposite), the glacier of Milk Lake, and the glacier of David — disappeared completely. The glacier of White Chuck (close to the Glacier Peak) is a particularly dramatic example. The glacier narrowed, passing from 3,1 km ² in 1958 with 0,9 km ² in 2002. In the same way, the Glacier of Boulder on the south-eastern side of the Mont Baker moved back of 450 m between 1987 and 2005, leaving a desert ground behind him. This retreat occurred for one period when the winters received little snow and the summers of the higher temperatures. In this area of the Cascades, the package of snow of winter decreased by 25% since 1946, and the temperatures of summer rose of 0,7 °C for the same period. This package of snow was reduced in spite of a small increase in precipitations of winter; it reflects hotter temperatures of driving winter to rain and thus of the pig iron and cast iron of glaciers even during the winter. Since 2005,67% of the glaciers of North Cascades in observation are in imbalance and will not survive the current climate. These glaciers will disappear unless the temperatures do not fall and that precipitations of snow do not increase. One expects that the remaining glaciers are stabilized with a great reduction of size, except if the climate continues with réchauffer .

On the sheltered slopes of the highest peaks of the National park of Glacier to the Montana, its glaciers éponymes decrease quickly. The National Park Service and US Geological Survey constituted of the plans of each glacier since decades. By comparing the photographs taken in the middle of the 19th century with the contemporary images, one notes in an obvious way that the glaciers of the park moved back notably since 1850. Photographs repeated, during decades for this time, have shown clearly that the glaciers in all the park, for example the glacier of Grinnell, move back. The larger glaciers now roughly have a third of the size than they had in 1850, and from the many smaller glaciers completely disappeared. In 1993,27% only of the zone of 99 km ² of the National park of Glacier which was covered by glaciers in 1850 remained covered with ice. The researchers think that, from here 2030, the major part of the glacial zone of the National park of Glacier will have disappeared unless the standard models of the climate do not reverse their course. The glacier of Grinnell is right one of these many glaciers of the National park of Glacier which are well documented by photographs since many decades. The photographs below clearly show the retreat of this glacier since 1938. |} The semi-arid climate of the Wyoming has always managed to support the dozen approximately small glaciers of the National park of Large Nipple, which show all, obviously, of the signs of retreat for the 50 last years. One expects that the Glacier of Schoolroom, located about at the south-west of the Grand Nipple, one of the glaciers most easily accessible from the park, disappears from here 2025. Research, between 1950 and 1999, showed that the glaciers of the national Forêt of Bridger-Nipple and of the national Forêt of Shoshone in the Assembly line Wind River narrowed of a third of their size for this period. The photographs indicate that the glaciers are today with half only of the size which they had at the end of the years 1890. Research also states that the glacial retreat was proportionally larger in years 1990 than in any other 100 last years decade. The Glacier of Gannett, on the north-eastern slope of the Peak of Gannett, is the largest glacier isolated from the Rocky Mountains southern known of Canada: it is reported that it lost more than 50% of its volume since 1920, of which almost the half since 1980. The glaciologists estimate that the remaining glaciers of Wyoming will disappear from here the medium from the 21e century if the climate continues like currently.

In the Rock Canadian, the glaciers is generally larger and wider than they are it in the south, in Montana. One of the glaciers most accessible from Rock Canadian is the Glacier of Athabasca, which is a glacier of discharge system of 325 km ² of the Ice-barrier of Colombia. This glacier moved back of 1 500 m since the end of the 19th century. The speed of retreat of the glacier, after one period of slow retreat of 1950 to 1980, increases again since 1980. The Glacier of Peyto in the Alberta covers a zone of approximately 12 km ²; it moved back quickly during first half 20th century, was stabilized as from 1966, then narrows again since 1976. The glacier of Illecillewaet, in the National park of the Glaciers of the Colombia-British, in Canada, moved back of 2 km since the first photographs which were taken in 1887.

There are thousands of glaciers in Alaska, although relatively little of them bear a name. The glacier of Colombia close to Valdez in the Sound of the Prince William moved back of 15 km during the 25 last years. Calved icebergs by this glacier were one of the causes of the oil slick of the Exxon Valdez, because the tanker had changed its road to avoid them. The glacier of Valdez is in the same sector, and although it does not calve of icebergs, it also moved back appreciably. “In 2005, an air overflight of the glaciers on the coast of Alaska identified of it more than one dozen, much being old coastal glaciers and which calve of the icebergs, including the Large Plate, Alsek, Bear, and the glaciers of Excelsior, which moved back quickly. 2 000 glaciers observed, 99% moved back. ”. The bay of Icy in Alaska is fed by three large glaciers — Guyot, Yahtse, and Tyndall — who underwent a loss length and thickness and, consequently, surface. In the years 1960, the glacier of Tyndall separated from the Guyot glacier, which moved back, and moved back itself of 24 km since, with an average of more than 500 m per annum.

The research program of Juneau Icefield supervised the glaciers of discharge system of Juneau Icefield since 1946. Western side of the ice-barrier, the terminus of the Glacier of Mendenhall, which runs out in the suburbs of Juneau, moved back of 580 Mr. On the nineteen glaciers of Juneau Icefield, eighteen move back, and only one, the glacier of Taku, advances. Since 1948, eleven of the glaciers moved back of more than 1 km — glacier of Antler: 5,4 km, glacier of Gilkey: 3,5 km, glacier of Norris: 1,1 km, glacier of Lemon Creek: 1,5 km. The glacier of Taku advances, at least since the year 1890, at the time where the naturalist John Muir observed a great face of vêlage of icebergs. In 1948, the adjacent Fjord was full, the glacier did not calve any more icebergs and could not continue its advance any more. In 2005, the glacier was with only 1,5 km of Taku Not and close blocking Taku Inlet. Between 1988 and 2005, the advance of the glacier of Taku was of 17 m on average per annum. For the period 1946– 88, its weight breakdown was very positive, filling in advance of fuel; however, since 1988, its weight breakdown is slightly negative, which should in the future slow down the advance of this powerful glacier.

The long-term recordings of the weight breakdown of the glacier Lemon Creek in Alaska show a light decline with time. The average annual statement of account for this glacier was, for the period of 1957 to 1976, − 0,23 m per annum. Between 1990 and 2005, the average annual statement of account was more and more had negative, with an average of − 1,04 m per annum. Measurements of altimetry (of altitude) repeated, for 67 glaciers of Alaska, give that their speed of thinning increased of more than one going factor 2 between the period of 1950 to 1995 (0,7 m per annum) and that going from 1995 to 2001 (1,8 m per annum). It is a systemic tendency with a loss of mass equal to the loss in thickness, which leads to increasing retreats of the glaciers — not only they move back, but they become increasingly thin. In the National park of Denali, the terminus of the glacier of Toklat moves back of 24 m per annum and the glacier of Cantwell of 10 m per annum. Documented well in Alaska, there are the glacial raw : they are glaciers known to advance quickly, and sometimes even of 100 m per day, although the reasons for which they do it are not entirely included/understood. The glaciers Varigated, Black Rapids, Muldrow, Susitna and Yanert are glacial examples of raw wools in Alaska which had fast forward movements in the past. These glaciers all are overall in retreat with, from time to time, of the short periods in advance.

In a great area surrounding the central and southernmost Andes of the Argentinian and the Chile, in sectors arid, resident of the populations whose survival depends on the water provisions that gets the cast iron of the glaciers. The water of the glaciers also feeds from the rivers which, in certain cases, pass in stoppings used for the hydroelectric energy. Certain researchers think that, from here 2030, several of the large icecaps on the tops of the Andes will disappear if the current trends of climate continue. In Patagonie, at the southernmost end of the continent, the large icecaps moved back of one kilometer since the beginning of the Nineties and of 10 km since the end of the year 1800. It was also observed that the glaciers of Patagonie moved back at a speed faster than in any other area of the sphere. Between the years 1945 and 1975, the Banquise of the north of Patagonie lost 93 km ² of surface of glacier, and between 1975 and 1996,174 km ², which indicates that the speed of retreat increases. Between the years 1944 and 1986, the southernmost ice cap of Patagonie showed, on 42 glaciers, a general tendency with the retreat; four of them were in balance and two have advanced. The greatest retreat was on the glacier O' Higgins which, for the period 1896-1995, moved back of 14,6 km. The Glacier Perito Moreno has 30 km length and is a major glacier of flow of the ice cap of Patagonie; it is also the glacier more visited of Patagonie. The glacier Perito Moreno is currently balances, but underwent of them frequent oscillations during the time 1947-96, with a total profit of 4,1 km. This glacier has advanced since 1947, and remained primarily stable since 1992. The glacier Perito Moreno is one of three glaciers of Patagonie known advanced, to have compared with several hundreds others in recul .

Tropical glaciers

The tropical glaciers are located between the Tropic of Cancer and the Tropic of Capricorn, in the area which connects the Latitude S 23° 26 ' 22" north and south of the equator. The tropical glaciers are most unusual of the glaciers, for a variety of reasons. Firstly, the tropics are the hottest part of planet. Secondly, the change of the seasons is minimal, with hot temperatures all the year, having for consequence an absence of cold season of winter when snow and the ice could accumulate. Thirdly, one finds few larger mountains in these areas, on which there is enough cold air for the establishment of the glaciers. All the glaciers located in the Tropics are on high peaks of isolated mountains. As a whole, the tropical glaciers are smaller than those found elsewhere and are most likely to give a prompt response with the changes of climate. A small increase in temperature of a few degrees only can have an almost immediate and unfavourable impact on the tropical glaciers.

With the African continent almost in entirety in the zones of tropical climate and Subtropical, the glaciers are limited there to two peaks isolated and the assembly line from Rwenzori. The Kilimandjaro, with 5 895 m, is the culminating point of the continent. Since 1912, the cover of the glacier of the top of Kilimandjaro apparently moved back of 75%, and its volume of ice decreased by 80% compared to what it was one century ago, all that being due to its retreat and its thinning. During the 14 years time of 1984 to 1998, a section of the glacier at the top of the mountain moved back of 300 Mr. a study of 2002 determined that if the current conditions continue, the glaciers at the top of Kilimandjaro will disappear at one time between 2015 and 2020 . A report/ratio of March 2005 indicated that there does not remain almost any more ice on the mountain, and it is the first time in 11 000 years that the naked ground appeared on parts of the sommet .

The Glacier of Furtwängler is located close to the top of Kilimandjaro. Between 1976 and 2000, the zone of this glacier was almost cut into two, while passing from 113 000 m ² with 60 000 m ². During the field work led at the beginning of 2006, the scientists discovered a large hole close to the center of the glacier. One expects that this hole, passing through the remaining thickness of 6 meters of the glacier to the subjacent rock, increases and duplicates the glacier in the two years which follow, about 2007. To the north of Kilimandjaro, the Mont Kenya extends, which, with 5 199 m, is the second highest mountain of the African continent. The Kenya Mount has a certain number of small glaciers which lost at least 45% of their mass since the middle of the 20th century. According to the research accumulated by the United States Geological Survey (USGS), in 1900, there were eighteen glaciers at the top of the Kenya mount, and in 1986, there remained only eleven about it. In 1900, the total zone covered by the glaciers was of 1,6 km ²; about the year 2000, there remained only approximately 25%, that is to say 0,4 km ². Towards the west of the Mounts Kilimandjaro and Kenya, the assembly line of Ruwenzori reaches the 5 109 Mr. the catches of sight of this assembly line obviously indicate a reduction marked, during last century, of the covered zones of ice. During the 35 years time between 1955 and 1990, the glaciers on the assembly line of Ruwenzori moved back from approximately 40%. One expects that because of their proximity with the heavy moisture of the area of the Congo, the glaciers of the assembly line of Ruwenzori move back at a speed slower than those of Kilimandjaro and Kenya.

A study, by glaciologists, of two small glaciers in South America indicates another retreat. In the Andes of north, more than 80% of all the ice is concentrated on the highest peaks in the form of small glaciers whose size is of approximately 1 km ². An observation of 1992 to 1998 of the glacier of Chacaltaya in Bolivia and glacier of Antizana in Ecuador indicated that between 0,6 m and 1,4 m of ice were lost per annum on each glacier. Over the same period, the figures, for the glacier of Chacaltaya, show a loss of 67% of its volume and 40% its thickness. The glacier of Chacaltaya lost 90% of its mass since 1940 and one expects that it disappears completely between 2010 and 2015. Research also states that since the middle of the years 1980, the speed of retreat of the two glaciers increased.

Further in the south, with the Peru, the Andes are at an altitude in general more raised, and there are roughly 722 glaciers which cover a surface of 723 km ². Research, in this area of the Andes, is developed but indicates all the same a total glacial retreat of 7% between 1977 and 1983. The Icecap of Quelccaya is the largest tropical icecap of the world, and all the glaciers of discharge system which leave there move back. In the case of the glacier of Qori Kalis, which is the principal glacier of discharge system of Quelccaya, the speed of retreat reached 155 m per annum for the three years period between 1995 to 1998. Since 1983, the molten ice formed a big lake in front of the glacier, and the naked ground appeared for the first time since thousands of years.

On the large island of New Guinea, the photographs show obviously, the area having been intensively flown over with the beginning of the year 1930, a massive glacial retreat. Because of the situation of the island in the tropical zone, there are practically no seasonal variations of temperature. Because of tropical situation, the level of rain and snowfalls, as well as the cloud cover, are foreseeable and regular all along the year, and there was no apparent change of the quantity of moisture fallen during the 20th century. The icecap of 7 km ² of the Pyramide Carstensz is largest of the island, and moved back since 1936, transforming a great glacial mass into several small. Among these small glaciers, research, between 1973 and 1976, showed a retreat of 200 m of the glacier of Meren and 50 m of the glacier of Carstenez. Northwall Firn, another large piece of the initial icecap located on the Carstenez pyramid, itself was cut in several glaciers since 1936. The research presented in 2004 showing images taken satellite IKONOS of the glaciers of New Guinea, provided a new dramatic version. The imagery indicated that in two years, of 2000 to 2002, East Northwall Firn had lost 4.5% of its glacial mass, West Northwall Firn 19.4% and Carstensz 6.8%. The researchers also discovered that, at a certain time between 1994 and 2000, the glacier of Meren completely disappeared. Separated from the glaciers of the pyramid Carstensz, another small icecap, known to have existed on the top of Puncak Trikora completely disappeared at one time between 1939 and 1962.

Polar regions

In spite of their proximity and importance for the human populations, the glaciers of mountain and valley located in the tropical areas and of semi-latitude represent only one weak fraction of the ice on the Earth. Approximately 99% of all the ice are located in the large ice caps of the the Antarctic and the polar and subpolar Greenland. These continuous ice caps on a continental scale, of 3 km and more thickness, cover most of the polar and subpolar grounds. Such of the rivers running of an enormous lake, the many glaciers of discharge system transport the ice of the edges of the ice cap to the ocean.

The insular nation of North Atlantic that is the Iceland shelters the Vatnajökull, which is the largest icecap of Europe. The glacier of Breiðamerkurjökull is one of the glaciers of discharge system of Vatnajökull, and moved back of at least 2 km between 1973 and 2004. At the beginning of the 20th century, Breiðamerkurjökull was prolonged of 250 m in the ocean, but since 2004, its terminus moved back of three kilometers inside the grounds. This retreat of the glacier updated a lagoon which extends quickly and which is filled with calved icebergs of the face of the glacier. The lagoon has 110 m of depth and almost doubled of size between 1994 and 2004. All the glaciers of discharge system of Vatnajökull except one, is roughly 40 glaciers, moved back in the year 2000. In Iceland, of the 34 glaciers studied between 1995 and 2000,28 proved to move back, four were stable and two advanced.

The Canadian Arctic islands have a certain number of substantial icecaps, including/understanding the icecap of Penny and that of Barnes on the island of Baffin, the icecap of Bylot on the island Bylot, and the icecap of Devon on the island Devon. All these icecaps are thinned and move back slowly. From 1995 to 2000, the icecaps of Barnes and Penny on the island of Baffin were thinned of more than 1 m per annum in low altitudes. Generally, between 1995 and 2000, icecaps in the Canadian Arctic one lost 25 km ³ of ice per annum. Between 1960 and 1999, the icecap of Devon lost 67 km ³ of ice, mainly in slimming. All the principal glaciers of discharge system along the Eastern edge of the icecap of Devon moved back of 1 with 3 km since 1960. On the plate of Hazen of the island of Ellesmere, the icecap of Simon lost 47% of his surface since 1959. If the current climatic conditions continue, the remaining ice of the plate of Hazen will have disappeared in 2050. August 13rd, 2005, the barrier of ice of Ayles was released from the northern coast of the island of Ellesmere, and this barrier of 66 square kilometers derived in the Arctic Glacial ocean. That followed the disintegration of the barrier of ice of Ward Hunt which took place in 2002. Ward Hunt lost 90% of its surface during last century.

The glaciers of the Arctic islands in the north of the Norway, the Finland and the Russia showed all of the obvious signs of retreat. In the Archipelago of Svalbard, the island of Spitzberg has many glaciers. Research indicates that the glacier of Hansbreen on the island of Spitzberg moved back of 1,4 km between 1936 and 1982, then of 400 m more for period the 16 years between 1982 to 1998. Blomstrandbreen, a glacier in the area of King' S Bay of the island of Spitzberg, moved back roughly of 2 km, during the 80 last years. Since 1960, the average retreat of Blomstrandbreen was of approximately 35 m per annum, and this average increased at a speed accelerated since 1995. In the same way, the glacier of Midre Lovenbreen moved back of 200 m between 1977 and 1995. In the archipelago of Nova Zembla, to the north of Russia, research indicates that, in 1952, there was 208 km of glaciers along the coast. In 1993, there was 198 of it; km, is 8% in less.

With the Greenland, one observed retreats at the glaciers of discharge system, which has like consequence an increase in the flow of ice and a destabilization of the weight breakdown of the ice cap which is the source. The years, since 2000, saw the retreat of several very large glaciers which, for a long time, had remained stable. Three glaciers which were studied — the Helheim glacier, the Kangerdlugssuaq glacier, and the Jakobshavn Isbræ — who alone drain 16% of the Inlandsis of Greenland. In the case of the glacier of Helheim, the researchers use satellite images to determine the movement and the retreat of the glacier. The satellite images and the air catches of sight of years 1950 and 1970 show that the face of the glacier remained at the same place during decades. In 2001, the glacier started to move back quickly, and, in 2005, it had moved back of a total of 7,2 km, accelerating, for this period, of 21,33 m per day with 33,5 m per day.

Jakobshavn Isbræ, in Western Greenland, an important glacier of discharge system of the ice cap of Greenland, is, since the last half-century, the fastest glacier of the world. It moves uninterrupted at speeds of more than 24 m per day until a terminus which remained stable since 1950, and perhaps even since longer. In 2002, the terminus floating of 12 km length of the glacier entered a fast phase of retreat, with a rupture on the face of ice and a floating terminus disaggregating and accelerating at a speed of retreat of more than 30 m per day. On a shorter scale of time, of 1998 to 2001, parts of the principal trunk of the glacier of Kangerdlugssuaq which moved with 15 m per day, moved with 40 m per day during the summer 2005. Not only Kangerdlugssuaq moved back, but it was also thinned of more than 100 Mr.

Thinning, acceleration and the retreat rapids of the glaciers of Helheim, Jakobshavns and Kangerdlugssuaq to Greenland, all in narrow association between them, suggest a common trip: increase in the cast iron of surface due to the regional warming of the climate. Current speeds of flow to the terminus are too fast to be only caused by the internal deformation of the ice, which implies that an increase in the slip at the base, reinforced by the additional production of melt waters is the probable cause of the increases speed. Terence Hughes, of the university of Maine, called that, in 1986, the effect Jakobshavns .

The Climat of the Antarctic is summarized in an intense cold and a great aridity. The major part of the world ice is contained in the large ice caps which cover the continent of the Antarctic. The most dramatic example of retreat of glacier on the continent is the loss great sections of the Barrière of ice of Larsen on the Péninsule the Antarctic. The barriers of ice are not stable when the ice of surface melts, and the collapse of the barrier of ice of Larsen was caused by hotter temperatures during the cast iron season, which led to the cast iron of surface, and the formation of not very deep ponds on the barrier of ice. Between 1995 and 2001, the barrier of ice of Larsen lost 2 500 km ² of surface. During the 35 days time starting the January 31st 2002, approximately 3 250 km ² of the surface of the barrier disaggregated. The barrier of ice is now to 40% of the size minimum which it had previously. The recent studies by the British Antactic Survey lay down a potential dislocation of the barrier of ice of George VI, due to the hot oceanic currents resulting from the Climate warming.

The Glacier of Prick Island, a glacier of discharge system of the Antarctic which runs in the Mer of Amundsen, was thinned of 3,5 ±0,9 m per annum and moved back of a total of 5 km in 38 years. The terminus of Island Prick is a barrier of drift ice, and the point on which it is with flood moves back of 1,2 km per annum. This glacier drains a substantial part of the Inlandsis of the Eastern Antarctic and was mentioned like the weak point of this ice cap. This same example of thinning and accelerated retreats is manifest on the glacier close to Thwaites. Moreover, the glacier of Dakshina Gangotri, a small glacier of discharge system of the Antarctic ice cap, moved back at a mean velocity of 0,7 m per annum between 1983 and 2002. On Peninsula the Antarctic, which is the only part of the Antarctic which is prolonged very in the north of the Cercle the Antarctic, there are hundreds of glaciers which move back. In a study of 244 glaciers on the peninsula, 212 moved back of 600 m on average of the position where they were when they were measured in 1953. The greatest retreat was seen on the glacier of Sjogren, which is now with 13 km more inside the grounds that it was not it in 1953. There are 32 glaciers which were measured like having advanced; however, these glaciers showed a modest advance of an average of 300 meters per glacier, which is appreciably smaller than the massive retreat observed.

Impacts of the retreat of the glaciers

The continuous retreat of the glaciers will have a certain number of impacts quantitatively different. In the sectors which strongly depend on the water run-off of the glaciers which found during the hottest months of the summer, the current retreat, if it continues, will end up exhausting the ice and will reduce appreciably or eliminate the flow. A reduction of the flow will affect the capacity of Irrigation for harvests and will reduce the flows of the torrents of summer, which are necessary to the maintenance on level of the stoppings and the tanks. This situation is particularly alarming for the irrigation in South America, where many artificial lakes are filled almost exclusively by the glacial cast iron. The countries of Central Asia are also historically dependant on the seasonal cast iron of the glaciers for the irrigation and the drinkable water provision. In Norway, in the Alps, and on the peaceful coast of the North-West of North America, the flow of the glaciers is important for the Hydro-électricité.

A consequence of this retreat was the made efforts, in the Alps, to slow down the loss of the glaciers. To delay the cast iron of the glaciers, which are employed by certain Austrian winter sports resorts, certain parts of the the Alps de Stubai and the glaciers of Pitztal were covered of plastic. In Switzerland, covering by plastic is also employed to reduce the cast iron of the ice which is used as ski slope. Although the fact of covering the glaciers by plastic can have advantages for the winter sports resorts on small scales, one does not expect that this practice is economically viable on more large scales.

Many of species of plants and sea water and fresh water animals depends on the water supply of the glaciers to ensure the cool water habitat to which they adapted. Certain fresh water fish species need this cool water to survive and to reproduce, and it is particularly true for the Saumon and the fardée trout. The reduction of melt water of the glaciers can lead to an insufficient flow of the torrents, which are necessary to these species to thrive. Deteriorations of the current sailors, due to the increase in the soft quantity coming from the cast iron of the glaciers, and potential deteriorations of the Circulation thermohaline of the oceans, can also have an impact on the fishing on which the human ones depend.

The potential of important a rise in the sea level depends mainly on a significant cast iron on the polar icecaps on Greenland and the Antarctic, since it is where most of glacial water is. The British Antarctic Survey determined, starting from climatic models, that for the 50 years to come at least, the snowfalls on the Antarctic continent should continue to exceed the glacial losses due to climate warming. The glacial quantity of loss on the Antarctic continent does not increase significantly, and it is not known if the continent will undergo a tendency to the warming or cooling, although the Antarctic peninsula was actually heated these last years, causing retreats of glaciers of this area. If any ice of the icecaps founded, the oceans would rise approximately 70 Mr. Cependant, with the small cast iron envisaged in the Antarctic, one estimates that the rise in the sea level would not exceed 50 cm with the 21e century, with an average rise in 4 mm per annum. The thermal dilation of the oceans, independently of the glacial cast iron, will contribute sufficiently to the doubling of these figures.

See too

References

Quotations

FRANCOU B. and VINCENT C.: Glaciers the climate proof (IRD, Belin, 2007, 274 p.)

General references

Internal bonds

History of the climate (before 1850)
Effects of climate warming since 1850

Various readings and external bonds

Expert: Alpine Most Gone Glaciers in 30 Years

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