Where is the largest glacier located? Scientists are sounding the alarm: the largest glacier in the world is melting at a record speed

Dedicated to my family, Yeoul, Kostya and Stas.

Glaciers on Earth and in the solar system

About ten percent of the land is covered with glaciers - perennial masses of snow, firna(from German. Firn - last year's packed granular snow) and ice, which have their own movement. These huge rivers of ice, cutting through valleys and grinding down mountains, crushing continents with their weight, store 80% of our planet's fresh water reserves.

The role of glaciers in the evolution of the globe and man is colossal. The last 2 million years of ice ages have become a powerful impetus for development for primates. Severe weather forced the hominid to struggle for existence in cold conditions, life in caves, the appearance and development of clothing, and the widespread use of fire. The sea level dropped due to the growth of glaciers and the drying of many isthmuses contributed to the migration of ancient people to America, Japan, Malaysia and Australia.

The largest centers of modern glaciation include:

Antarctica - terra incognita, discovered only 190 years ago and became the record holder for the absolute minimum temperature on Earth: -89.4 ° C (1974); at this temperature, kerosene freezes;
Greenland, deceptively called the Greenland, is the "icy heart" of the Northern Hemisphere;
Canadian arctic archipelago and the majestic Cordillera, where one of the most picturesque and powerful centers of glaciation is located - Alaska, a real modern relic of the Pleistocene;
the most grandiose region of glaciation in Asia - the “abode of snows” the Himalayas and Tibet;
"roof of the world" Pamir;
Andes;
"heavenly mountains" Tien Shan and "black scree" Karakorum;
Surprisingly, there are even glaciers in Mexico, tropical Africa (the “sparkling mountain” of Kilimanjaro, Mount Kenya and the Rwenzori Mountains) and New Guinea!

The science that studies glaciers and other natural systems whose properties and dynamics are determined by ice is called glaciology(from lat. glacies- ice). "Ice" is a mono-mineral rock that occurs in 15 crystalline modifications for which there are no names, but only code numbers. They differ in different types of crystal symmetry (or shape of the unit cell), the number of oxygen atoms in the cell, and other physical parameters. The most common modification is hexagonal, but there are also cubic and tetragonal, etc. We conditionally designate all these modifications of the solid phase of water with one single word “ice”.

Ice and glaciers are found everywhere in the solar system: in the shadow of the craters of Mercury and the Moon; in the form of permafrost and polar caps of Mars; in the core of Jupiter, Saturn, Uranus and Neptune; on Europa - the satellite of Jupiter, completely, like a shell, covered with many kilometers of ice; on other satellites of Jupiter - Ganymede and Callisto; on one of the moons of Saturn - Enceladus, with the purest ice in the Solar System, where jets of water vapor burst hundreds of kilometers high from cracks in the ice shell at supersonic speed; possibly on the satellites of Uranus - Miranda, Neptune - Triton, Pluto - Charon; finally, in comets. However, by coincidence of astronomical circumstances, the Earth is a unique place where the existence of water on the surface is possible in three phases at once - liquid, solid and gaseous.

The fact is that ice is a very young mineral of the Earth. Ice is the latest and most superficial mineral, not only in terms of specific gravity: If we single out the temperature stages of differentiation of matter in the process of the formation of the Earth as an initially gaseous body, then ice formation is the last step. It is for this reason that snow and ice on the surface of our planet are everywhere near the melting point and are subject to the slightest changes in climate.

But if, under the temperature conditions of the Earth, water passes from one phase to another, then for cold Mars (with a temperature difference from –140 ° C to + 20 ° C), water is mainly in the crystalline phase (although there are sublimation processes that even lead to the formation clouds), and much more significant phase transitions are no longer experienced by water, but by carbon dioxide, falling as snow when the temperature drops, or evaporating when it rises (thus, the mass of the Martian atmosphere changes from season to season by 25%).

Growth and melting of glaciers

For the emergence of a glacier, a combination of climatic conditions and relief is necessary, under which the annual amount of snowfall (taking into account snowstorms and avalanches) will exceed the loss ( ablation) due to melting and evaporation. Under such conditions, a mass of snow, firn and ice arises, which, under the influence of its own weight, begins to flow down the slope.

The glacier is of atmospheric sedimentary origin. In other words, every gram of ice, be it a modest glacier in the Khibiny or a giant ice dome of Antarctica, was brought by weightless snowflakes that fall year after year, millennium after millennium in the cold regions of our planet. Thus, glaciers are a temporary stop of water between the atmosphere and the ocean.

Accordingly, if glaciers grow, then the level of the world's oceans drops (for example, to 120 m during the last ice age); if they shrink and retreat, then the sea rises. One of the consequences of this is the existence on the shelf zone of the Arctic of areas of relic underwater permafrost covered by the water column. During the epochs of glaciation, the continental shelf, which was exposed due to lowering of the sea level, gradually froze through. After the re-emergence of the sea, the permafrost formed in this way was under the water of the Arctic Ocean, where it still exists due to the low temperature of sea water (-1.8°C).

If all the world's glaciers melted, sea levels would rise by 64–70 meters. Now the annual advance of the sea on land occurs at a rate of 3.1 mm per year, of which about 2 mm is the result of an increase in the volume of water due to thermal expansion, and the remaining millimeter is the result of the intensive melting of the mountain glaciers of Patagonia, Alaska and the Himalayas. Recently, this process has been accelerating, increasingly affecting the glaciers of Greenland and West Antarctica, and, according to the latest estimates, sea level rise by 2100 could be 200 cm. This will significantly change coastline, will erase more than one island from the world map and take away hundreds of millions of people in the prosperous Netherlands and poor Bangladesh, in the Pacific Ocean and the Caribbean, and in other parts of the globe coastal territories with total area over 1 million square kilometers.

types of glaciers. icebergs

Glaciologists distinguish the following main types of glaciers: mountain peak glaciers, ice domes and shields, slope glaciers, valley glaciers, reticulate glaciers systems(typical, for example, for Svalbard, where ice completely fills the valleys, and only the tops of the mountains remain above the surface of the glacier). In addition, as a continuation of terrestrial glaciers, marine glaciers and ice shelves, which are floating or bottom-supported plates with an area of up to several hundred thousand square kilometers (the largest ice shelf - the Ross Glacier in Antarctica - occupies 500 thousand km 2, which is approximately equal to the territory of Spain).

Ice shelves rise and fall with the ebb and flow of the tides. From time to time, giant ice islands break off from them - the so-called table icebergs, up to 500 m thick. Only one tenth of their volume is above the water, which is why the movement of icebergs depends more on sea currents than on winds, and because of which icebergs have repeatedly caused the death of ships. Since the Titanic tragedy, the icebergs have been closely monitored. Nevertheless, iceberg-caused disasters still occur today - for example, the crash of an oil tanker Exxon Valdez On March 24, 1989, off the coast of Alaska, the ship was trying to avoid hitting an iceberg.

The tallest iceberg recorded in the Northern Hemisphere was 168 meters high. And the largest table iceberg ever described was observed on November 17, 1956 from the icebreaker Glazier ( USS Glacier): its length was 375 km, its width was more than 100 km, and its area was more than 35 thousand km 2 (larger than Taiwan or Kyushu)!

Since the 1950s, the commercial transportation of icebergs to countries experiencing a shortage of fresh water has been seriously discussed. In 1973, one of these projects was proposed - with a budget of 30 million dollars. This project attracted the attention of scientists and engineers from all over the world; It was led by Saudi Prince Mohammed al-Faisal. But due to numerous technical problems and unresolved issues (for example, an iceberg turned over due to melting and a shift in the center of mass can, like an octopus, drag any cruiser towing it to the bottom), the implementation of the idea is postponed for the future.

Wrap an iceberg incommensurable in size with any ship on the planet and transport the melting to warm waters and shrouded in mist ice island across thousands of kilometers of the ocean - yet beyond the power of man.

It is curious that when the iceberg melts, it hisses like a soda (" bergy selzer”) - this can be seen in any polar institute if you are treated to a glass of whiskey with pieces of such ice. This ancient air, compressed under high pressure (up to 20 atmospheres), escapes from the bubbles when it melts. The air was trapped during the transformation of snow into firn and ice, after which it was compressed by the enormous pressure of the mass of the glacier. The story of the 16th-century Dutch navigator Willem Barents about how the iceberg near which his ship stood (near Novaya Zemlya) suddenly shattered into hundreds of pieces with a terrible noise, terrifying all the people on board.

Glacier Anatomy

The glacier is conditionally divided into two parts: the upper - food area, where the accumulation and transformation of snow into firn and ice takes place, and the lower - ablation area where the snow accumulated over the winter melts. The line separating these two regions is called glacier feeding boundary. The newly formed ice gradually flows from the upper feeding region to the lower ablation region, where melting occurs. Thus, the glacier is included in the process of geographic moisture exchange between the hydrosphere and the troposphere.

Irregularities, ledges, an increase in the slope of the glacial bed change the relief of the glacial surface. In steep places where stresses in the ice are extremely high, ice falls and cracks can occur. Himalayan glacier Chator(mountainous region of Lagul, Lahaul) begins with a grandiose icefall 2100 m high! A real mess of giant columns and towers of ice (the so-called serac) icefall is literally impossible to cross.

The infamous icefall on the Nepalese Khumbu glacier at the foot of Everest has cost the lives of many climbers trying to pass through this devilish surface. In 1951, a group of climbers led by Sir Edmund Hillary, during a reconnaissance of the surface of the glacier, along which the route of the first successful ascent of Everest was later laid, crossed this forest of ice columns up to 20 meters high. As one of the participants recalled, a sudden rumble and a strong trembling of the surface under their feet greatly frightened the climbers, but, fortunately, the collapse did not occur. One of the subsequent expeditions, in 1969, ended tragically: 6 people were crushed under the tones of unexpectedly collapsed ice.

The depth of cracks in glaciers can exceed 40 meters, and their length can be several kilometers. Covered with snow, such dips into the darkness of the glacial body are a death trap for climbers, snowmobiles or even all-terrain vehicles. Over time, due to the movement of ice, cracks can close. There are cases when non-evacuated bodies of people who fell into cracks were literally frozen into the glacier. So, in 1820, on the slope of Mont Blanc, three guides were knocked down and thrown into the rift by an avalanche - only 43 years later their bodies were found melted next to the tongue of the glacier, three kilometers from the site of the tragedy.

Melt water can significantly deepen the cracks and turn them into part of the drainage system of the glacier - glacial wells. They can reach 10 m in diameter and penetrate hundreds of meters deep into the glacial body to the very bottom.

A lake of meltwater on the surface of a glacier in Greenland, 4 km long and 8 meters deep, was recently recorded as disappearing in less than an hour and a half; at the same time, the water flow per second was greater than that of Niagara Falls. All this water reaches the ice bed and serves as a lubricant that speeds up the sliding of ice.

Glacier speed

Naturalist and mountaineer Franz Josef Hugi in 1827 made one of the first measurements of the speed of ice movement, and unexpectedly for himself. A hut was built on the glacier for the night; when Hugi returned to the glacier a year later, he was surprised to find that the hut was in a completely different place.

The movement of glaciers is due to two different processes - sliding ice mass under its own weight along the bed and viscoplastic flow(or internal deformation when ice crystals change shape under stress and move relative to each other).

The speed of the glacier can range from a few centimeters to more than 10 kilometers per year. So, in 1719, the advance of glaciers in the Alps was so fast that the inhabitants were forced to turn to the authorities with a request to take action and force " damn beasts(quote) go back. Complaints about the glaciers were written to the king by the Norwegian peasants, whose farms were destroyed by the advancing ice. It is known that in 1684 two Norwegian peasants were brought before a local court for non-payment of rent. When asked why they refused to pay, the peasants replied that their summer pastures were covered with advancing ice. The authorities had to make observations to make sure that the glaciers were really advancing - and as a result, we now have historical data on the fluctuations of these glaciers!

The fastest glacier on Earth was considered the glacier Colombia in Alaska (15 kilometers per year), but more recently, the glacier came out on top Jakobshavn(Jakobshavn) in Greenland (see fantastic video of its collapse presented at a recent glaciological conference). The movement of this glacier can be felt by standing on its surface. In 2007, this giant river of ice, 6 kilometers wide and over 300 meters thick, producing about 35 billion tons of the world's tallest icebergs annually, was moving at a speed of 42.5 meters per day (15.5 kilometers per year)!

Pulsating glaciers can move even faster, the sudden movement of which can reach 300 meters per day!

The speed of ice movement within the ice sheet is not the same. Due to friction with the underlying surface, it is minimal near the glacier bed and maximal on the surface. This was measured for the first time after a steel pipe was sunk into a 130-meter-deep hole drilled in the glacier. Measurement of its curvature made it possible to construct a profile of the ice movement velocity.

In addition, the speed of ice in the center of the glacier is higher compared to its marginal parts. The first transverse profile of the uneven distribution of glacier velocities was demonstrated by the Swiss scientist Jean Louis Agassiz in the forties of the 19th century. He left slats on the glacier, putting them in a straight line; a year later, the straight line turned into a parabola, with its apex pointing downstream of the glacier.

As a unique example illustrating the movement of a glacier, the following tragic event can be cited. On August 2, 1947, the plane, which was on a commercial flight from Buenos Aires to Santiago, disappeared without a trace 5 minutes before landing. An intensive search turned up nothing. The secret was revealed only half a century later: on one of the slopes of the Andes, at the peak Tupungato(Tupungato, 6800 m), in the area of melting the glacier, fragments of the fuselage and the bodies of passengers began to melt from the ice. Probably in 1947, due to poor visibility, the plane crashed into a slope, provoked an avalanche and was buried under its deposits in the glacier accumulation zone. It took 50 years for the fragments to go through the full cycle of the glacier substance.

God's plow

The movement of glaciers destroys rocks and transports a huge amount of mineral material (the so-called moraine) - starting from breakaway rock blocks and ending with fine dust.

Thanks to the transport of moraine deposits, many surprising finds have been made: for example, fragments of boulders containing inclusions of copper carried by the glacier have been used to find the main deposits of copper ore in Finland. In the United States, in the deposits of terminal moraines (by which one can judge the ancient distribution of glaciers), gold brought by glaciers (Indiana) and even diamonds weighing up to 21 carats (Wisconsin, Michigan, Ohio) were found. This has led many geologists to look north to Canada, where the glacier came from. There, between Lake Superior and Hudson Bay, kimberlite rocks were described - however, scientists could not find kimberlite pipes.

The very idea that glaciers move was born out of a dispute about the origin of the huge erratic boulders. This is what geologists call large boulders (“wandering stones”) that are completely different in mineral composition from their surroundings (“a granite boulder on limestone looks as strange to trained eyes as a polar bear on the sidewalk,” one researcher liked to repeat).

One of these boulders (the famous Thunder Stone) became the pedestal for the Bronze Horseman in St. Petersburg. In Sweden, a limestone boulder 850 meters long is known, in Denmark - a giant block of Tertiary and Cretaceous clays and sands 4 kilometers long. In England, in the county Huntingdonshire, 80 km north of London, an entire village was even built on one of the erratic slabs!

"Plowing out" of solid bedrock by a glacier in the Alps can be up to 15 mm per year, in Alaska - 20 mm, which is comparable to river erosion. The erosive, transporting and accumulating activity of glaciers leaves such a colossal imprint on the face of the Earth that Jean-Louis Agassiz called glaciers "God's plow". Many landscapes of the planet are the result of the activity of glaciers, which covered about 30% of the earth's land 20 thousand years ago.

All geologists recognize that it is with the growth, movement and degradation of glaciers that the most complex geomorphological formations on Earth are associated. Erosive landforms such as punishment, similar to giant chairs, and glacial cirques, trogs. Numerous moraine landforms nunataks And erratic boulders, eskers And fluvioglacial deposits. Are formed fjords, with a wall height of up to 1500 meters in Alaska and up to 1800 meters in Greenland and a length of up to 220 kilometers in Norway or up to 350 kilometers in Greenland ( Nordwestfjord Scoresby & Sund East cost). The sheer walls of the fjords have been chosen by base jumpers (see base jumping) all over the world. Crazy height and slope allow you to make long jumps up to 20 seconds free fall into the void created by the glaciers.

Dynamite and glacier thickness

The thickness of a mountain glacier can be tens or even hundreds of meters. The largest mountain glacier in Eurasia - Fedchenko Glacier in the Pamirs (Tajikistan) - has a length of 77 km and a thickness of more than 900 m.

The absolute champions are the ice sheets of Greenland and Antarctica. For the first time, the thickness of ice in Greenland was measured during the expedition of the founder of the theory of continental drift Alfred Wegener in 1929-30. To do this, dynamite was blown up on the surface of the ice dome and the time required for the echo (elastic vibrations) reflected from the stone bed of the glacier to return to the surface was determined. Knowing the speed of propagation of elastic waves in ice (about 3700 m/s), it is possible to calculate the thickness of the ice.

Today, the main methods for measuring the thickness of glaciers are seismic and radio sounding. It has been determined that the maximum ice depth in Greenland is about 3408 m, in Antarctica 4776 m ( Astrolabe subglacial basin)!

Subglacial Lake Vostok

As a result of seismic radar sounding, researchers made one of the last geographical discoveries XX century - the legendary subglacial Lake Vostok.

In absolute darkness, under the pressure of a four-kilometer ice layer, there is a reservoir of water with an area of 17.1 thousand km 2 (almost like Lake Ladoga) and a depth of up to 1500 meters - scientists called this water body Lake Vostok. It owes its existence to its location in a geological fault and geothermal heating, which may support the life of bacteria. Like other water bodies of the Earth, Lake Vostok, under the influence of the gravity of the Moon and the Sun, undergoes ebbs and flows (1–2 cm). For this reason, and because of the difference in depths and temperatures, water is supposed to circulate in the lake.

Similar subglacial lakes have been found in Iceland; in Antarctica, more than 280 such lakes are known today, many of them are connected by subglacial channels. But Lake Vostok is isolated and the largest, which is why it represents the greatest interest for scientists. Oxygen-rich water at a temperature of –2.65°C is at a pressure of around 350 bar.

The assumption of a very high oxygen content (up to 700–1200 mg/l) in lake water is based on the following reasoning: the measured ice density at the firn-to-ice transition boundary is about 700–750 kg/m 3 . This relatively low value is due to the large number of air bubbles. Reaching the lower part of the ice sheet (where the pressure is about 300 bar and any gases "dissolve" in the ice, forming gas hydrates), the density increases to 900–950 kg/m 3 . This means that each specific unit of volume, melting at the bottom, brings at least 15% of the air from each specific unit of surface volume (Zotikov, 2006)

The air is released and dissolved in the water, or possibly collected under pressure in the form of air siphons. This process took place over 15 million years; accordingly, when the lake was formed, a huge amount of air melted out of the ice. There are no analogues of water with such a high oxygen concentration in nature (the maximum in lakes is about 14 mg/l). Therefore, the spectrum of living organisms that could tolerate such extreme conditions is reduced to a very narrow range. oxygenophilic; among known to science There are no species capable of living in such conditions.

Biologists around the world are extremely interested in obtaining water samples from Lake Vostok, since the analysis of ice cores obtained from a depth of 3667 meters as a result of drilling in the immediate vicinity of Lake Vostok itself showed the complete absence of any microorganisms, and these cores are already of interest to biologists. do not represent. But a technical solution to the issue of opening and penetrating an ecosystem sealed for more than ten million years has not yet been found. The point is not only that now 50 tons of kerosene-based drilling fluid is poured into the well, which prevents the well from being closed by ice pressure and freezing of the drill, but also that any mechanism created by man can upset the biological balance and pollute the water, introducing into it not pre-existing microorganisms.

Perhaps similar subglacial lakes, or even seas, also exist on Jupiter's moon Europa and Saturn's moon Enceladus, under tens or even hundreds of kilometers of ice. It is on these hypothetical seas that astrobiologists place their greatest hopes when searching for extraterrestrial life inside the solar system and are already making plans for how, with the help of nuclear energy (the so-called NASA cryobot), it will be possible to overcome hundreds of kilometers of ice and penetrate into the water space. (Thus, on February 18, 2009, NASA and the European Space Agency ESA officially announced that Europe would be the destination of the next historic mission to explore the solar system, scheduled to arrive in orbit in 2026.)

Glacioisostasia

The colossal volumes of modern ice sheets (Greenland - 2.9 million km 3, Antarctica - 24.7 million km 3) for hundreds and thousands of meters push the lithosphere into the semi-liquid asthenosphere (this is the upper, least viscous part of the earth's mantle). As a result, parts of Greenland are more than 300 m below sea level, and Antarctica is 2555 m ( Bentley Subglacial Trench)! In fact, the continental beds of Antarctica and Greenland are not single massifs, but huge archipelagos of islands.

After the disappearance of the glacier, the so-called glacioisostatic uplift, due to the simple principle of buoyancy described by Archimedes: lighter lithospheric plates slowly rise to the surface. For example, part of Canada or the Scandinavian Peninsula, which were covered by an ice sheet more than 10 thousand years ago, still continues to experience isostatic uplift at a rate of up to 11 mm per year (it is known that even the Eskimos paid attention to this phenomenon and argued about whether whether it is land or whether the sea is sinking). It is assumed that if all the ice in Greenland melts, the island will rise by about 600 meters.

Difficult to find habitable area more prone to glacioisostatic uplift than islands Replot Skerry Guard in the Gulf of Bothnia. Over the past two hundred years, during which the islands have risen from under the water by about 9 mm per year, the land area has increased here by 35%. The inhabitants of the islands gather once every 50 years and joyfully share new land plots.

Gravity and ice

A few years ago, when I was graduating from university, the question of the mass balance of Antarctica and Greenland in the context of global warming was ambiguous. It was very difficult to determine whether the volume of these giant ice domes is decreasing or increasing. There have been hypotheses that perhaps warming brings large quantity precipitation, and as a result, glaciers do not decrease, but grow. Data from the GRACE satellites launched by NASA in 2002 clarified the situation and disproved these ideas.

The more mass, the more gravity. Since the surface of the globe is not uniform and includes gigantic mountain ranges, spacious oceans, deserts, etc., the Earth's gravitational field is also not uniform. This gravitational anomaly and its change with time are measured by two satellites - one follows the other and registers the relative deviation of the trajectory when flying over objects of different masses. For example, roughly speaking, when flying over Antarctica, the satellite trajectory will be a little closer to the Earth, and over the ocean, on the contrary, further.

Long-term observations of flybys in the same place make it possible to judge from the change in gravity how the mass has changed. The results showed that the volume of Greenland's glaciers is annually reduced by about 248 km3, and that of Antarctica's glaciers by 152 km3. By the way, according to the maps compiled with the help of GRACE satellites, not only the process of reduction in the volume of glaciers was recorded, but also the above-mentioned process of glacioisostatic uplift of continental plates.

For example, for the central part of Canada, due to glacioisostatic uplift, an increase in mass (or gravity) was recorded, and for neighboring Greenland, a decrease due to the intensive melting of glaciers.

The planetary significance of glaciers

According to Academician Kotlyakov, " the development of the geographic environment throughout the Earth is determined by the balance of heat and moisture, which to a large extent depends on the distribution and transformation of ice. The transformation of water from solid to liquid requires a huge amount of energy. At the same time, the transformation of water into ice is accompanied by the release of energy (approximately 35% of the external heat exchange of the Earth)". The spring melting of ice and snow cools the earth, does not allow it to warm up quickly; ice formation in winter - warms, does not allow to cool quickly. If there were no ice, then the temperature differences on Earth would be much greater, the summer heat would be stronger, and the frosts would be more severe.

Taking into account the seasonal snow and ice cover, it can be considered that from 30% to 50% of the Earth's surface is occupied by snow and ice. The most important importance of ice for the planet's climate is associated with its high reflectivity - 40% (for snow covering glaciers - 95%), due to which there is a significant cooling of the surface over vast areas. That is, glaciers are not only priceless reserves of fresh water, but also sources of strong cooling of the Earth.

Interesting consequences of the reduction in the mass of glaciation in Greenland and Antarctica were the weakening of the gravitational force that attracts huge masses of ocean water, and a change in the angle of the earth's axis. The first is a simple consequence of the law of gravity: the smaller the mass, the smaller the attraction; the second is that the Greenland ice sheet loads the globe asymmetrically, and this affects the rotation of the Earth: a change in this mass affects the adaptation of the planet to a new mass symmetry, due to which the earth's axis shifts annually (up to 6 cm per year).

The first guess about the gravitational influence of the mass of glaciation on sea level was made by the French mathematician Joseph Alphonse Adhemar, 1797–1862 (he was also the first scientist to point out the connection between ice ages and astronomical factors; after him, the theory was developed by Kroll (see James Croll) and Milankovitch). Adémar tried to estimate the thickness of ice in Antarctica by comparing the depths of the Arctic and Southern oceans. His idea boiled down to the fact that the depth of the Southern Ocean is much greater than the depth of the Arctic Ocean due to the strong attraction of water masses by the giant gravitational field of the Antarctic ice cap. According to his calculations, to maintain such a strong difference between the water levels of the north and south, the thickness of the ice cover of Antarctica had to be 90 km.

Today it is clear that all these assumptions are wrong, except that the phenomenon does occur, but with a smaller magnitude - and its effect can extend radially up to 2000 km. The consequences of this effect are that the rise in global sea level due to glacier melt will be uneven (although current models mistakenly assume a uniform distribution). As a result, in some coastal areas, the sea level will rise by 5–30% above the average value (the northeastern part of the Pacific and the southern part of Indian Oceans), and in some - below ( South America, western, southern, and eastern coasts of Eurasia) (Mitrovica et al., 2009).

Frozen millennia - a revolution in paleoclimatology

On May 24, 1954, at 4 am, Danish paleoclimatologist Willi Dansgaard was cycling through deserted streets to the central post office with a huge envelope covered with 35 stamps and addressed to the editors of a scientific publication. Geochimica et Cosmochimica Acta. The envelope contained the manuscript of the article, which he was in a hurry to publish as soon as possible. He was struck by a fantastic idea that would later make a real revolution in the climate sciences of ancient times and which he would develop all his life.

Dansgaard's research has shown that the amount of heavy isotopes in sediments can be used to determine the temperature at which they were formed. And he thought: what, in fact, prevents us from determining the temperature of past years, simply by taking and analyzing the chemical composition of the water of that time? Nothing! The next logical question is where to get ancient water? In glacial ice! Where can I get ancient glacial ice? In Greenland!

This amazing idea was born a few years before the technology for deep drilling of glaciers was developed. When the technological issue was resolved, an amazing thing happened: scientists discovered an incredible way to travel into the past of the Earth. With every centimeter of ice drilled, their drill blades began to plunge deeper and deeper into paleohistory, revealing ever more ancient secrets of the climate. Each ice core recovered from the well was a time capsule.

Having deciphered the secret script written with hieroglyphs of a whole variety of chemical elements and particles, spores, pollen and bubbles of ancient air hundreds of thousands of years old, one can obtain invaluable information about irrevocably gone millennia, worlds, climates and phenomena.

Time machine 4000 m deep

Age of the oldest Antarctic ice from maximum depths (more than 3500 meters), the search for which is still ongoing, is estimated at about one and a half million years. Chemical analysis of these samples provides insight into ancient climate Earth, the news of which was brought and preserved in the form of chemical elements by weightless snowflakes that fell from heaven hundreds of thousands of years ago.

This is similar to the story of Baron Munchausen's journey through Russia. During the hunt, somewhere in Siberia, there was a terrible frost, and the baron, trying to call his friends, blew his horn. But to no avail, because the sound froze in the horn and thawed only the next morning in the sun. Approximately the same thing is happening today in the cold laboratories of the world under electron tunneling microscopes and mass spectrometers. Ice cores from Greenland and Antarctica are many kilometers long time machines going back centuries and millennia. The legendary well drilled under the Vostok station (3677 meters) remains the deepest to this day. Thanks to it, for the first time, the relationship between changes in temperature and the content of carbon dioxide in the atmosphere over the past 400 thousand years was shown, and an ultra-long anabiosis of microbes was discovered.

Detailed paleoreconstructions of air temperature are built on the basis of the analysis of the isotopic composition of the cores - namely, the percentage of the heavy oxygen isotope 18 O (its average content in nature is about 0.2% of all oxygen atoms). Water molecules containing this oxygen isotope evaporate harder and condense more easily. Therefore, for example, in water vapor above the sea surface, the content of 18 O is lower than in sea water. Conversely, water molecules containing 18 O are more likely to participate in condensation on the surface of snow crystals formed in clouds, due to which their content in precipitation is higher than in the water vapor from which precipitation is formed.

The lower the temperature of precipitation formation, the stronger this effect is, that is, the more 18 O in them. Therefore, by estimating the isotopic composition of snow or ice, one can also estimate the temperature at which precipitation was formed.

And then, using the known altitude temperature profiles, to estimate what the surface air temperature was hundreds of thousands of years ago, when a snowflake just fell on the Antarctic dome to turn into ice, which will be extracted today from a depth of several kilometers during drilling.

Annually falling snow carefully preserves on the petals of snowflakes not only information about the air temperature. The number of parameters measured in laboratory analysis is currently enormous. Tiny ice crystals record the signals of volcanic eruptions, nuclear tests, Chernobyl disaster, anthropogenic lead content, dust storms, etc.

The amount of tritium (3 H) and carbon-14 (14 C) can be used to date the age of the ice. Both of these methods have been elegantly demonstrated on vintage wines - the years on the labels match perfectly with the dates calculated from the analyzes. That's just an expensive pleasure, and wine A There is a lot of lime to analyze...

Information about the history of solar activity can be quantified by the content of nitrates (NO 3 –) in glacial ice. Heavy nitrate molecules are formed from NO in the upper atmosphere under the influence of ionizing cosmic radiation (protons from solar flares, galactic radiation) as a result of a chain of transformations of nitrogen oxide (N 2 O) entering the atmosphere from soil, nitrogen fertilizers and fuel combustion products (N 2O + O → 2NO). After formation, the hydrated anion precipitates with precipitation, some of which is eventually buried in the glacier along with the next snowfall.

Isotopes of beryllium-10 (10 Be) make it possible to judge the intensity of deep space cosmic rays bombarding the Earth, and changes in the magnetic field of our planet.

On the change in the composition of the atmosphere over last hundreds For thousands of years, small bubbles in ice have told, like bottles thrown into the ocean of history, preserving for us samples of ancient air. They showed that over the past 400 thousand years, the content of carbon dioxide (CO 2) and methane (CH 4) in the atmosphere today is the highest.

Today, laboratories already store thousands of meters of ice cores for future analysis. Only in Greenland and Antarctica (that is, not counting the mountain glaciers), a total of about 30 km of ice cores were drilled and extracted!

Ice age theory

The beginning of modern glaciology was laid by the theory of ice ages that appeared in the first half of the 19th century. The idea that in the past glaciers extended hundreds and thousands of kilometers to the south seemed unthinkable before. As one of the first Russian glaciologists Peter Kropotkin (yes, the same one) wrote, “ at that time, belief in an ice sheet that reached Europe was considered an unacceptable heresy ...».

The founder and main defender of the glacial theory was Jean Louis Agassiz. In 1839 he wrote: The development of these huge ice sheets should have led to the destruction of all organic life on the surface. The lands of Europe, once covered with tropical vegetation and inhabited by herds of elephants, hippos and giant carnivores, were buried under the overgrown ice covering the plains, lakes, seas and mountain plateaus.<...>Only the silence of death remained... The springs dried up, the rivers froze, and the rays of the sun rising over the frozen shores... met only the whisper of northern winds and the rumble of cracks opening in the middle of the surface of a giant ocean of ice.»

Most of the geologists of that time, who had little knowledge of Switzerland and the mountains, ignored the theory and were not even able to believe in the plasticity of ice, let alone imagine the thickness of the glacial strata described by Agassiz. This continued until the first scientific expedition to Greenland (1853-55), led by Elisha Kent Kane, reported on the complete ice sheet of the island (“ an ocean of endless ice»).

The recognition of the theory of ice ages had an incredible impact on the development of modern natural science. The next key issue was the reason for the change of ice ages and interglacials. At the beginning of the 20th century, the Serbian mathematician and engineer Milutin Milankovic developed a mathematical theory describing the dependence of climate change on changes in the orbital parameters of the planet, and devoted all his time to calculations to prove the validity of his theory, namely, to determine the cyclic change in the amount of solar radiation entering the Earth (so called insolation). The Earth, spinning in the void, is in a gravitational web of complex interaction between all objects in the solar system. As a result of orbital cyclic changes ( eccentricity earth orbit, precession And nutation tilt of the earth's axis) the amount of solar energy reaching the Earth changes. Milankovitch found the following cycles: 100 thousand years, 41 thousand years and 21 thousand years.

Unfortunately, the scientist himself did not live to see the day when his insight was elegantly and flawlessly proven by paleo-oceanographer John Imbrie. Imbri assessed past temperature changes by examining cores from the bottom of the Indian Ocean. The analysis was based on the following phenomenon: different types of plankton prefer different, strictly defined temperatures. Every year, the skeletons of these organisms settle on the ocean floor. By lifting this layered cake from the bottom and identifying the species, one can judge how the temperature has changed. The paleotemperature variations determined in this way surprisingly coincided with the Milankovitch cycles.

Today it is known that cold glacial eras were followed by warm interglacials. Complete glaciation of the globe (according to the so-called theory " snowy coma”) presumably took place 800–630 million years ago. The last glaciation of the Quaternary period ended 10 thousand years ago.

The ice domes of Antarctica and Greenland are relics of past glaciations; having disappeared now, they will not be able to recover. During periods of glaciation, continental ice sheets covered up to 30% of the earth's land mass. So, 150 thousand years ago, the thickness of glacial ice over Moscow was about a kilometer, and over Canada - about 4 km!

The era in which human civilization now lives and develops is called ice age, interglacial period. According to calculations made on the basis of Milankovitch's orbital theory of climate, the next glaciation will come in 20,000 years. But the question remains whether the orbital factor can overpower the anthropogenic one. The fact is that without the natural greenhouse effect, our planet would have an average temperature of -6°C, instead of today's +15°C. That is, the difference is 21°C. The greenhouse effect has always existed, but human activity greatly enhances this effect. Now the content of carbon dioxide in the atmosphere is the highest in the last 800 thousand years - 0.038% (whereas the previous maximums did not exceed 0.03%).

Today, glaciers almost all over the world (with some exceptions) are rapidly shrinking; the same goes for sea ice, permafrost and snow cover. It is estimated that half of the world's mountain glaciation will disappear by 2100. About 1.5-2 billion people living in various countries of Asia, Europe and America may face the fact that the rivers fed by the melt waters of glaciers will dry up. At the same time, rising sea levels will rob people of their land in the Pacific and Indian Oceans, the Caribbean and Europe.

Wrath of the Titans - glacial catastrophes

Increasing anthropogenic impact on the planet's climate can increase the likelihood of natural disasters associated with glaciers. Masses of ice have gigantic potential energy, the realization of which can have monstrous consequences. Some time ago, a video of a small column of ice collapsing into the water and the subsequent wave that washed away a group of tourists from nearby rocks circulated on the Internet. In Greenland, similar waves 30 meters high and 300 meters long were observed.

The glacial catastrophe that occurred in North Ossetia on September 20, 2002 was recorded on all seismometers in the Caucasus. glacier collapse Kolka provoked a giant glacial collapse - 100 million m 3 of ice, stones and water swept through the Karmadon Gorge at a speed of 180 km per hour. Mudflow splashes tore loose deposits of the sides of the valley in places up to 140 meters high. 125 people died.

One of the worst glacial disasters in the world was the collapse of the northern slope of the mountain Huascaran in Peru in 1970. An earthquake of magnitude 7.7 triggered an avalanche of millions of tons of snow, ice and rocks (50 million m3). The collapse stopped only after 16 kilometers; two cities, buried under the rubble, turned into a mass grave for 20 thousand people.

Another type of hazard from glaciers is the outburst of dammed glacial lakes that occur between a melting glacier and a terminus. moraine. The height of the terminal moraines can reach 100 m, creating a huge potential for the formation of lakes and their subsequent outburst.

In 1555, a lake outburst in Nepal covered an area of about 450 km 2 with deposits, and in some places the thickness of these deposits reached 60 m (the height of a 20-story building)! In 1941, the intense melting of Peru's glaciers contributed to the growth of dammed lakes. The breakthrough of one of them killed 6,000 people. In 1963, as a result of the movement of the pulsating Medvezhiy glacier, a lake 80 meters deep appeared in the Pamirs. When the ice bridge was broken, a devastating flow of water rushed down the valley and the subsequent mudflow, which destroyed the power plant and many houses.

The most monstrous breakthrough glacial lake came across the Hudson Strait at sea Labrador about 12,900 years ago. Breakthrough Lake Agassiz, which was larger than the Caspian Sea, caused an abnormally rapid (in 10 years) cooling of the North Atlantic climate (by 5°C in England), known as Early Dryas(see Younger Dryas) and found in the analysis of Greenland ice cores. A huge amount of fresh water disturbed thermohaline circulation Atlantic Ocean, which blocked the transfer of heat by the current from low latitudes. Today, such a spasmodic process is feared in connection with global warming, which is desalinating the waters of the North Atlantic.

Today, due to the accelerated melting of the world's glaciers, the size of dammed lakes is increasing and, accordingly, the risk of their breakthrough is growing.

In the Himalayas alone, 95% of whose glaciers are rapidly melting, there are about 340 potentially dangerous lakes. In 1994, in Bhutan, 10 million cubic meters of water, pouring out of one of these lakes, traveled 80 kilometers at great speed, killing 21 people.

According to forecasts, the outburst of glacial lakes could become an annual disaster. Millions of people in Pakistan, India, Nepal, Bhutan and Tibet will not only face the inevitable reduction of water resources due to the disappearance of glaciers, but will also face the deadly danger of outburst lakes. Hydroelectric power plants, villages, infrastructure can be destroyed in an instant by terrible mudflows.

Another type of glacial catastrophes - lahars, resulting from volcanic eruptions covered by ice caps. The meeting of ice and lava gives rise to gigantic volcanic mudflows, typical of the land of "fire and ice" Iceland, Kamchatka, Alaska, and even on Elbrus. Lahars can reach monstrous sizes, being the largest among all types of mudflows: they can be up to 300 km long and 500 million m 3 in volume.

On the night of November 13, 1985, residents of the Colombian city Armero(Armero) woke up from a crazy noise: a volcanic mudflow swept through their city, washing away all the houses and structures in its path - its bubbling slurry claimed the lives of 30 thousand people. Another tragic incident occurred on a fateful Christmas evening in 1953 in New Zealand - a lake outburst from an icy volcano crater provoked a lahar that washed away railroad bridge literally in front of the train. The locomotive and five cars with 151 passengers dived and disappeared forever in the rushing stream.

In addition, volcanoes can simply destroy glaciers - for example, the monstrous eruption of a North American volcano St. Helens(Saint Helens) demolished 400 meters of the mountain along with 70% of the volume of glaciers.

people of ice

The harsh conditions in which glaciologists have to work are perhaps one of the most difficult that modern scientists have to face. B O Most of the field observations involve working in cold hard-to-reach and remote parts of the globe, with harsh solar radiation and insufficient oxygen. In addition, glaciology often combines mountaineering with science, thus making the profession deadly.

Frostbite is familiar to many glaciologists, because of which, for example, a former professor of my institute had his fingers and toes amputated. Even in a comfortable laboratory, temperatures can drop to -50°C. In the polar regions, all-terrain vehicles and snowmobiles sometimes fall into 30-40-meter cracks, the most severe blizzards often make the high-altitude workdays of researchers a real hell and claim more than one life every year. This is a job for strong and hardy people who are sincerely dedicated to their work and the endless beauty of the mountains and poles.

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Global warming threatens to melt the glaciers. In the news now and then they talk about the threat of the disappearance of one or another icy river. In the meantime, you should hurry up and see a selection of the most beautiful glaciers in the world.

1. Biafo Glacier, Pakistan

Due to its secluded location in the heart of a highland region in northern Pakistan, the Biafo Glacier has remained virtually untouched by civilization. Traveling to the huge "Snow Lake" along the edge of the ice plain will require several days, which, due to the magnificence of the surrounding flora and fauna, will not seem boring. Hiking is best done in good physical shape. Otherwise, there is a great opportunity, instead of contemplating the pristine beauty of nature, to admire only the earth under your feet.

2. Perito Moreno Glacier, Argentina

IN national park There are as many as 13 glaciers in Lago Argentino, but the Perito Moreno glacier is recognized as the most beautiful of them. The icy river, whose height is 60 meters, divides alpine lake Argentino into 2 parts: the Rich Sea and the South Sea. Making their way through the glacier along the channel, the waters of these seas gradually destroy it, and thanks to this, tourists can admire the view of huge blocks of ice falling into the water. On the territory of the reserve you can meet guanacos, rhea ostriches and even a condor - the largest bird in the world.

3. Glacier Bay, Alaska

Glacier Bay - giant national park, which is located on southeast coast Alaska and is under the protection of UNESCO. Hiking tours on the territory of the reserve are practically absent - inspection of glaciers is carried out from an airplane or helicopter. However, you can watch the sparkling ice without leaving the hotel, which is located right on the territory of the park. In addition, the icebergs that have broken off from the edge of the glacier and the heaving ice blocks can be admired by cruising along the coast. In the surrounding waters of the reserve, you can stumble upon whales, walruses and even dolphins, and bears and deer live in coastal forests.

4. Furtwängler Glacier, Tanzania

Since the beginning of the century, the glacier, located almost on the equator, has been gradually melting and, according to scientists' forecasts, will completely disappear by 2020. Furtwängler is located at an altitude of more than 5000 meters, on the northern side of Kilimanjaro, near its summit.

5. Pasterze Glacier, Austria

The Pasterze, the largest of the 925 Austrian glaciers, is also slowly disappearing and, according to predictions, by 2100 less than half of its current size will remain. In the meantime, this seemingly motionless 9-kilometer-long icy river slowly descends from a height of 3500 meters to the foot of the Glosgrokner mountain.

6. Vatnajokul Glacier, Iceland

Iceland's largest glacier accounts for approximately 80 percent of the island's total ice cover, which takes its name from the frozen water. Its huge fields, dotted with cracks, stretch over 8,300 square kilometers. Competing with the cold beauty of ice is the lava frozen in the intricate curves of the nearby volcanic landscape. Favorite tourist activities: descending into ice crevices, rock climbing on a glacier, snow rafting and swimming in thermal springs ice caves.

7. Yulong Glacier, China

Scientists have more than once foreshadowed the disappearance of China's southernmost glacier, but systematic observations of its movement, which have been carried out since 1982, refute pessimistic forecasts: depending on climate fluctuations, the glacier retreats several hundred meters up, then descends again. The lower border of the glacier is currently located at an altitude of about 4200 meters above sea level, and getting to it is not so easy due to the strong rarefied air.

8. Fox and Franz Josef Glaciers, New Zealand

Frozen waterfall flowing down from western slope In the Southern Alps, glaciers come so close to subtropical evergreen forests that their proximity seems completely unnatural.

9. Athabasca Glacier, Canada

Another rapidly melting glacier, which is considered the most beautiful in North America, has recently lost almost half of its volume. Currently, it has a length of only about 6 kilometers. Such a rapid melting turned into the fact that the glacier is constantly in motion and therefore it is strictly forbidden to walk along it alone, without a guide.

10. Antarctic

And, of course, most of the ice and snow can be seen in Antarctica, which, probably, was the reason for the increased popularity of the continent due to global warming. If in the 1990s 6-7 thousand people traveled here during the season, then last year the number of tourists reached 45,000, in connection with which the number of incidents that harm the ecology of the region increased. Therefore, quite recently, 28 countries conducting scientific activities in Antarctica signed an agreement to limit tourism to the mainland.

Importance glaciers play to replenish all the rivers of the world. 16 million sq. km - such is their total area, this is about 11% of the entire land. They contain huge reserves of fresh water. There are a huge number of them in Russia, with an area of about 60 thousand square meters. km. Glaciers in Russia are divided into two types, according to the method of their formation:

Integumentary. This is the vast majority of all glacial systems in the country. These include the ice of Franz Josef Land, Novaya Zemlya, Severnaya Zemlya and other Arctic islands. The average thickness on the islands in the North Arctic Ocean- from 100 to 300 meters. They store huge reserves of fresh water.
Mountain glaciers of Russia. Their share in the total area is only 5%. These are glacial accumulations of the mountain ranges of the Caucasus, the Urals, Kamchatka. For their formation, two conditions must be met: negative air temperatures and precipitation. Often, if it often rains in the mountains, then they are accompanied by warm weather.

Variety of glaciers

There are many classifications of glaciers, including mountain glaciers. What varieties of them can be found in our country?

Snow spots. Accumulation of snow in gentle valleys and slopes.
Glaciers of stepped slopes. The snow mass gathers at the shady foot of the mountain and is fed by avalanches.
Hanging glaciers. They are located on steep slopes, as if hanging over it. They are small in size, but they are dangerous, as they can break down.
Car glaciers. Snow masses in armchair-like valleys, with a steep back wall.
Glaciers of volcanic peaks. They occupy the tops of the mountains.
Transitional glaciers. They have a common beginning - the top of the ridge, but the stakes are in opposite directions from it.
Norwegian type. This type of glaciers is transitional from mountain to cover. Ice caps of plateau-like peaks spread downwards. Having reached the edge, they go down in separate foci.
Valleys are located in mountain valleys.

The mountain glaciers of Russia do not remain the same in area. Some shrink, others grow, and there are those that change their position as they move. What are the largest glaciers in Russia? List of 5 largest mountain systems with multi-year ice as follows.

Caucasus

It is the largest accumulation center of mountain glaciers. On the Russian part i.e. on its northern slope, huge masses are concentrated, with a total area of 1400 sq. km. This is more than 2000 glaciers. Basically they small size, up to 1 sq. km in diameter. The largest glacier in Russia is a complex in Kabardino-Balkaria with an area of over 120 sq. km. Another large snowy peak in the Caucasus is the top of the extinct Kazbek volcano. It is here that more than 60% of all ice in the Caucasus is concentrated. A feature is their alpine character. Russian part snowy peaks of the Greater Caucasus is located on its northern slope, it is smoother and more extended, in contrast to the southern one. Here, more than 70% of the ice of the Greater Caucasus. The southern slope is steep and steep, it has 30% of the snows of the Caucasus Mountains. The glaciation of this ridge is important for feeding the rivers that originate here. These are Belaya, Zelenchuk, Laba - and - Ardon, Urukh, Baksan. The glaciers of the Caucasus Mountains are retreating and their area is shrinking. Although this decrease is insignificant, the feeding of the rivers suffers from it. Over a century, the level of the snow line has risen by 70-75 cm. Sometimes there is a short-term advance of ice in some areas.

Altai

In second place in the list of the largest mountain glaciers in the country are the snows of Altai. Here, in the south of Siberia, there are about 1,500 hearths, which occupy an area of more than 900 square meters. km. The largest glaciations are on the Katunsky, South-Chuysky and North-Chuysky ridges. Large masses are concentrated on Mount Belukha, where the great Altai river Katun and its tributaries. These places have become the most favorite and popular among climbers throughout Altai. Here is the Akkem glacier. Some believe that he has a special energy, and charges his visitors with it. Another snowy peak of Altai is Aktru. The mountain is famous for its enormous temperature difference. In summer there is unbearable heat, and in winter - severe cold. For this, Aktru is considered a local cold point. The temperature here drops to minus 62ºС. But even despite such difficult climatic conditions, there are a lot of people who want to see these glaciers in Russia. Pictures of their landscapes are simply mesmerizing.

Kamchatka

The present-day glaciation of the peninsula is significant. The snow masses here are larger than in the Caucasus. There are about 450 of them, with a total area of over 900 square meters. km. Their main concentration is on the Sredinny Ridge and the Klyuchevskaya group. Russia's glaciers in Kamchatka have an interesting feature. They are classified as so-called caldera, because of the method of formation. They are formed in calderas and craters of volcanoes and hills, of which there are a huge number on the peninsula. In Kamchatka, the warm season is short, and the snow that falls on the tops of the hills does not have time to melt. Another feature of the Kamchatka snows is their low location. Glaciers descend from the peaks to a height of 1600 meters. Great importance in the life of the snows have volcanic eruptions. During the eruption, the glaciers actively melt and fill the rivers with melt water.

Koryak Range

It is also called It is located in the Far East, captures the Chukotka autonomous region and Kamchatka Territory. Total number There are 1330 glaciers here, and their area is more than 250 sq. km. The Koryak highland consists of short ridges and ridges that stretch from the northeast to the southwest. Russian glaciers in the Far East are elongated, up to 4 km long. They are located very low, much lower than the snow line, at the level of 700-1000 meters. This is due to climatic conditions and the proximity of the cold sea. Another glacier in Russia - - its highest point is at 2562 meters.

Mountains of Suntar-Khayat

These glaciers of Russia are located on the territory of Yakutia and the Khabarovsk Territory. There are 208 of them here, with a total area of over 200 square kilometers. The ridge stretched for 450 km, and its highest point - Mount Cape Khaya - at a level of almost 3000 meters. In addition to mountain glaciers, there are about 800 sq. km tyrynov. This is the name of a large perennial icing, which is formed when groundwater freezes.

The thickness of such ice is usually about 8 meters. Suntar Khayata is the watershed of such major rivers Siberia, like Indigirka, Aldan, and rivers of the Sea of Okhotsk basin.

These amazing pictures British tourists show what the largest glacier in Europe looks like inside. Its area is about 8,200 square kilometers, and its thickness is 1,000 meters at its thickest point. In 2008, the glacier and its surroundings were declared a national park.

1. Vatnajökull is the largest glacier on the island of Iceland and occupies as much as 8% of its territory. It is also the largest glacier in Europe in terms of ice volume, it is the third largest in terms of territory (after the North Island glacier and the Eustfonna glacier). (Photo by Einar Runar Sigurdsson):

2. The average ice thickness here is 400 m, the maximum is 1000 m. A whole kilometer! (Photo by Einar Runar Sigurdsson):

3. Under the glacier, as under many glaciers in Iceland, there are several volcanoes. (Photo by Einar Runar Sigurdsson):

4. In South East Iceland, where the glaciers are located, the ice cave season lasts from November to March, but some of them are not safe all year round. (Photo by Einar Runar Sigurdsson):

"Some ice caves filled with water inside, and you can get there only in the coldest time of winter, when the water in the lakes freezes. Other caves are very unstable and dangerous even in winter period, and you should not go there: beauty is deceptive.

6. It's amazingly beautiful here! (Photo by Einar Runar Sigurdsson):

7. The glacier feeds several glacial lakes, including Jokulsarlon, the largest glacial lagoon in Iceland. (Photo by Einar Runar Sigurdsson):

8. A few more photos of the largest glacier in terms of ice volume in Europe. (Photo by Einar Runar Sigurdsson):

9. (Photo by Einar Runar Sigurdsson):

10. (Photo by Einar Runar Sigurdsson):