How much water is there in Antarctica? Antarctic ice sheet

Lying within 50-60° south latitude, where the warmer and colder waters of the oceans meet. The area of Antarctica is 52.5 million km." The seas included in this area are very rough, sometimes reaching heights of more than 20 meters. In winter, the water freezes and ice surrounds Antarctica in a ring, the width of which ranges from 500 to 2000 km. In summer, currents carry ice north along with. According to scientists, more than 100 thousand icebergs of various sizes float simultaneously off the coast of Antarctica. He was the first to penetrate the Antarctic waters in 1502, discovering a number of islands.

Antarctica - polar region on the south side globe. Here, inside the Arctic Circle, there is an icy continent. It is approximately twice as large - 14 million km2. The average height of the continent is 2040 meters. has not stopped to this day. In the central part, the ice cover rises to almost 4000 meters. Individual peaks of the Antarctic - a ridge stretching along the coast - rise above the ice to 5000 meters or more. At the same time, the height of the continent would be less if there were no ice on it. There is a lot of it here - 24 million km3. This is more than 90% of all fresh water on Earth, which is stored here in a frozen state. The average thickness of the ice cover is more than 1,700 meters, the maximum is more than 4,000 meters. It is thanks to ice that Antarctica looks like a huge white dome on. If the ice suddenly melted, it would raise the level by 60 meters, which would entail a reduction in the area of all continents, including Antarctica itself, which would become an archipelago - a cluster of islands, since a significant part of the continent under the ice dome lies below the level ocean.

Antarctica is the coldest of all continents. In the winter months, frosts can reach -90°C. In summer the frosts are less, only -20°C. There is no rain in Antarctica: precipitation here falls in the form of snow. The center of the mainland and its coasts are very different: in the center there is calm and clear skies almost all year round, and on the shores there are strong winds and... there it can reach 90 m/s. Such winds can easily carry heavy objects over considerable distances. Dry snow, rushing at high speed, is capable of sawing through thick ropes and polishes metal to a shine.

Icy Antarctica is considered the main “refrigerator” of our planet and affects its climate. The continent receives a very large amount of solar heat. It turns out that in the south polar summer you can’t leave the room without sunglasses; the skin tans quickly. But Antarctica's ice reflects up to 90%, and the continent does not warm up. And during the polar night it becomes very cold.

Most of Antarctica is icy, only life glimmers near the coast. Where a few rocks protrude from under the ice, there are oases of life on the mainland. This is only 0.02% of its territory. The organic world of Antarctica is poor; only rare mosses, lichens and algae inhabit it. Penguins are the main decoration of the continent. Whales and seals live in the waters of the seas.

Antarctica does not belong to any state; no one lives there permanently. Nevertheless, 16 countries have founded their research stations here, where various studies of the nature of this continent are carried out. Antarctica is a continent of peace and cooperation. Any military preparations are prohibited within its borders. No country can claim it as their land. This is legally enshrined in an international treaty, which was signed on December 1, 1959.

The discovery of Antarctica occurred in 1820 by Russian navigators and M.P. Lazarev, and in December 1911, a Norwegian expedition, followed by an English expedition, reached the South Pole.

: the average height of the continent is 2350 m; extensive plateau, IGY valley, Queen Maud Land and Prince Charles mountains, subglacial mountains of Gamburtsev and Vernalsky; Transantarctic Mountains

Additional information: Antarctica is washed; only 0.3% of the land is not covered with ice; the average thickness of the ice cover is 1800 m; There is no permanent population on the mainland.

Antarctica is a continent located in the very south of the Earth; the center of Antarctica approximately coincides with the southern geographic pole. The continent of Antarctica is washed by the waters of the Atlantic, Indian and Pacific oceans, sometimes unofficially separated into a separate Southern Ocean.

Where is Antarctica

In the southernmost part of our planet there is a huge continent covered eternal ice. Antarctica in the south is not only the coldest, but also the most deserted continent. It is washed by the waters of 13 seas.

1820 is the year of the discovery of Antarctica. It was then that Russian navigators F.F. Bellingshausen and M.P. Lazarev discovered it during a round-the-world Antarctic expedition. The researchers gave the discovered land the definition of “ice continent” and compiled the first description of the continent.

Rice. 1. Antarctica

The area of Antarctica is about 14,107,000 square meters. km (of which ice shelves - 930,000 sq. km, islands - 75,500 sq. km). Moreover, the average surface height of Antarctica is the highest of all continents.

In addition, Antarctica is characterized by following features:

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lowest relative humidity;
the strongest sustained wind;
the most intense solar radiation.

Antarctica is an independent territory and does not belong to any state. At the same time, on its lands you can find many research stations from different countries peace.

Relief

Vast territories of Antarctica are occupied by a permanent ice sheet, at the base of which there is continental relief, and only 0.3% (about 40 thousand sq. km.) of its area is free of ice.

The Transantarctic Mountains, which cross almost the entire continent, divide Antarctica into two parts that have different origins and geological structure:

West Antarctica. It consists of a group of mountainous islands connected by ice.
East Antarctica. In the east there is a high (ice thickness is 4100 m above sea level) ice-covered plateau.

In West Antarctica there is also the deepest depression of the continent - the Bentley Deep, the depth of which is 2555 m below sea level.

Climate

Antarctica has an extremely harsh cold climate. The area is considered the Earth's pole of cold. It should be noted that the winter months in Antarctica (as throughout the southern hemisphere) are June, July and August, and the summer months are December, January and February.

In East Antarctica, at the Soviet Antarctic station "Vostok" on July 21, 1983, the lowest air temperature on Earth in the entire history of meteorological measurements was recorded: 89.2 degrees below zero.

Another feature of East Antarctica's meteorology is the katabatic winds caused by its dome-shaped topography. Due to the large amount of icy dust carried by the wind, horizontal visibility in such winds is very low.

Rice. 2. Strong katabatic winds

It is not surprising that due to such harsh climatic conditions there is no permanent population in Antarctica. Research stations operate here throughout the year. In winter, about 1,000 people are employed on the continent; in summer, their number increases to 4,000 people. IN lately Tourism is becoming increasingly popular.

Wildlife

Plants and animals are most common in the coastal zone. Terrestrial vegetation in ice-free areas exists mainly in the form of various types of mosses and lichens.

Antarctic animals are completely dependent on the coastal ecosystem of the Southern Ocean: due to the paucity of vegetation, all food chains coastal ecosystems begin in the waters surrounding Antarctica. Antarctic waters are especially rich in zooplankton - the main food source for many species of fish, squid, seals, penguins, and cetaceans.

Rice. 3. Penguins

The main topic of concern to scientists around the world is global warming. As a result of rising temperatures and melting glaciers, tundra began to actively form on the Antarctic Peninsula. Scientists predict that in 100 years the first trees may appear in Antarctica.

What have we learned?

From the geography course for the 7th grade, we learned what area Antarctica occupies, where it is located, as well as what features of climate and nature it is characterized by. The continent, located in the very south of the Earth, is the coldest. On its endless icy deserts, only sparse vegetation can be found occasionally, and animals live only in the coastal zone.

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Relief and ice cover

Antarctica is the highest continent on Earth; the average height of the continent's surface above sea level is more than 2000 m, and in the center of the continent it reaches 4000 meters. Most of this height is made up of a permanent ice cover of the continent, under which the continental relief is hidden and only ~5% of its area is free from ice - mainly in West Antarctica and the Transantarctic Mountains: islands, sections of the coast, the so-called. “dry valleys” and individual ridges and mountain peaks (nunataks) rising above the icy surface. The Transantarctic Mountains, crossing almost the entire continent, divide Antarctica into two parts - West Antarctica and East Antarctica, which have different origins and geological structures. In the east there is a high (highest elevation of the ice surface ~4100 m above sea level) ice-covered plateau. Western part consists of a group of mountainous islands connected by ice. On the Pacific coast are the Antarctic Andes, whose altitude exceeds 4000 m; the highest point of the continent - 4892 m above sea level - the Vinson Massif of the Sentinel Ridge. In West Antarctica there is also the deepest depression of the continent - the Bentley Basin, probably of rift origin. The depth of the ice-filled Bentley Trench reaches 2555 m below sea level.

The Antarctic ice sheet is the largest on our planet and is approximately 10 times larger in area than the next largest, the Greenland Ice Sheet. It contains ~30 million km³ of ice, that is, 90% of all land ice. It is dome-shaped with the surface increasing in steepness towards the coast, where it is flanked in many places by ice shelves. The average thickness of the ice layer is 2500-2800 m, reaching a maximum value in some areas of East Antarctica - 4800 m. The accumulation of ice on the ice sheet leads, as in the case of other glaciers, to the flow of ice into the ablation (destruction) zone, which acts as coast of the continent (see Fig. 3); the ice breaks off in the form of icebergs. The annual volume of ablation is estimated at 2500 km³.

The peculiarity of Antarctica is large area ice shelves (low (blue) areas of West Antarctica), accounting for ~10% of the area above sea level; these glaciers are sources of icebergs of record sizes, significantly exceeding the size of the icebergs of the outlet glaciers of Greenland; for example, in 2000, the largest known ice cap broke off from the Ross Ice Shelf. at the moment(2005) iceberg B-15 with an area of over 10,000 km². In winter (summer in the northern hemisphere), the area of sea ice around Antarctica increases to 18 million km², and in summer it decreases to 3-4 million km².

The Antarctic ice sheet formed about 14 million years ago, apparently facilitated by the rupture of the bridge connecting South America and the Antarctic Peninsula, which led, in turn, to the formation of the Antarctic circumpolar current (Western Wind Current) and the isolation of Antarctic waters from the World Ocean - these waters make up the so-called Southern Ocean.

Seismic activity

Antarctica is a tectonically calm continent with little seismic activity, manifestations of volcanism are concentrated in western Antarctica and are associated with the Antarctic Peninsula, which arose during the Andean period of mountain building. Some of the volcanoes, especially island volcanoes, have erupted in the last 200 years. The most active volcano in Antarctica is Erebus. It is called “the volcano guarding the path to the South Pole.”

Climate

Antarctica has an extremely harsh cold climate. The absolute pole of cold is located in East Antarctica, where temperatures down to −89.2 °C were recorded (the area of the Vostok station).

Another feature of the meteorology of East Antarctica is katabatic winds, caused by its dome-shaped topography. These stable southerly winds arise on fairly steep slopes of the ice sheet due to the cooling of the air layer near the ice surface, the density of the near-surface layer increases, and it flows down the slope under the influence of gravity. The thickness of the air flow layer is usually 200-300 m; Due to the large amount of ice dust carried by the wind, horizontal visibility in such winds is very low. The strength of the katabatic wind is proportional to the steepness of the slope and greatest strength reaches in coastal areas with a high slope towards the sea. The katabatic winds reach their maximum strength in the Antarctic winter - from April to November they blow almost continuously around the clock, from November to March - at night or when the Sun is low above the horizon. In summer, during the daytime, due to the heating of the surface layer of air by the sun, katabatic winds along the coast cease.

Data on temperature changes from 1981 to 2007 show that the temperature background in Antarctica changed unevenly. For West Antarctica as a whole, an increase in temperature has been observed, while for East Antarctica no warming has been detected, and even some negative trend has been noted. It is unlikely that the melting process in Antarctica will increase significantly in the 21st century. On the contrary, as temperatures rise, the amount of snow falling on the Antarctic ice sheet is expected to increase. However, due to warming, more intense destruction of ice shelves and acceleration of the movement of Antarctica's outlet glaciers, throwing ice into the World Ocean, is possible.

Inland waters

In the 90s of the 20th century, Russian scientists discovered the subglacial non-freezing Lake Vostok - the largest of the Antarctic lakes, having a length of 250 km and a width of 50 km; the lake holds about 5,400 thousand km³ of water.

In January 2006, geophysicists Robin Bell and Michael Studinger from the American Lamont-Doherty Geophysical Observatory discovered the second and third largest subglacial lakes, with an area of 2000 km² and 1600 km² respectively, located at a depth of about 3 km from the surface of the continent. They reported that this could have been done earlier if the data from the 1958-1959 Soviet expedition had been analyzed more thoroughly. In addition to these data, satellite data, radar readings and measurements of the force of gravity on the surface of the continent were used.

In total, as of 2007, more than 140 subglacial lakes were discovered in Antarctica.

Biosphere

The biosphere in Antarctica is represented in four “arenas of life”: coastal islands and ice, coastal oases on the mainland (for example, the “Banger Oasis”), the nunataks arena (Mount Amundsen near Mirny, Mount Nansen on Victoria Land, etc.) and the ice sheet arena .

Plants and animals are most common in the coastal zone. Terrestrial vegetation in ice-free areas exists mainly in the form of various types of mosses and lichens and does not form a closed cover (Antarctic moss-lichen deserts).

Antarctic animals are entirely dependent on the coastal ecosystem of the Southern Ocean: due to the paucity of vegetation, all food chains of any significance in coastal ecosystems begin in the waters surrounding Antarctica. Antarctic waters are especially rich in zooplankton, primarily krill. Krill directly or indirectly form the basis of the food chain of many species of fish, cetaceans, squid, seals, penguins and other animals; There are no completely land mammals in Antarctica; invertebrates are represented by approximately 70 species of arthropods (insects and arachnids) and nematodes living in soils.

Terrestrial animals include seals (Weddell, crabeater seals, leopard seals, Ross, elephant seals) and birds (several species of petrels, two species of skuas, Adélie penguins and emperor penguins).

In the freshwater lakes of continental coastal oases - “dry valleys” - there are oligotrophic ecosystems inhabited by blue-green algae, roundworms, copepods (cyclops) and daphnia, while birds (petrels and skuas) fly here occasionally.

Nunataks are characterized only by bacteria, algae, lichens and severely suppressed mosses; only skuas, following people, occasionally fly onto the ice sheet.

There is an assumption about the presence in subglacial lakes of Antarctica, such as Lake Vostok, of extremely oligotrophic ecosystems, practically isolated from the outside world.

In 1994, scientists reported a rapid increase in the number of plants in Antarctica, which seems to confirm the hypothesis of global warming of the planet.

The Antarctic Peninsula and its adjacent islands have the most favorable climatic conditions on the mainland. It is here that the only flowering plants in the region grow - Antarctic meadowsweet and Quito colobanthus.

Exploring Antarctica

The first ship to cross the Antarctic Circle belonged to the Dutch; it was commanded by Dirk Geeritz, who sailed in the squadron of Jacob Magyu. In 1559, in the Strait of Magellan, Geeritz's ship lost sight of the squadron after a storm and went south. When it dropped to 64° S. sh., was found there high ground. In 1671 La Roche discovered South Georgia; Bouvet Island was discovered in 1739; In 1772, in the Indian Ocean, Yves-Joseph Kerglen, a French naval officer, discovered an island named after him.

Almost simultaneously with Kerglen’s voyage, James Cook set off from England on his first voyage to the southern hemisphere, and already in January 1773 his ships “Adventure” and “Resolution” crossed the Antarctic Circle at the meridian 37°33′E. d. After a difficult struggle with ice, he reached 67°15′ S. sh., where he was forced to turn north. In December 1773, Cook again set off for the southern ocean, crossing it on December 8 and at parallel 67°5′ S. w. was covered in ice. Having freed himself, Cook went further south and at the end of January 1774 reached 71°15′ S. sh., southwest of Tierra del Fuego. Here an impenetrable wall of ice prevented him from going further. Cook was one of the first to reach the south polar seas and, having encountered solid ice in several places, declared that it could not be penetrated further. They believed him, and for 45 years no polar expeditions were undertaken.

In 1819, Russian sailors F.F. Bellingshausen and M.P. Lazarev on the sloops of war “Vostok” and “Mirny” visited South Georgia and tried to penetrate deep into the South Arctic Ocean. For the first time, in January 1820, almost on the Greenwich meridian, they reached 69°21′ S. sh.; then, leaving the Arctic Circle, Bellingshausen walked along it east to 19° east. d., where he crossed it again and reached in February 1820 again almost the same latitude (69°6′). Further east, he rose only to the 62° parallel and continued his path along the outskirts floating ice. Then, on the meridian of the Balleny Islands, Bellingshausen reached 64°55′, and in December 1820 reached 161°w. d., passed the southern polar circle and reached 67°15′ S. latitude, and in January 1821 reached 69°53′ S. w. Almost at the 81° meridian, he discovered the high coast of the island of Peter I, and having gone further east, inside the southern polar circle, the coast of Alexander I Land. Thus, Bellingshausen was the first to complete a complete voyage around Antarctica at latitudes from 60° to 70°.

After this, the study of the coast of the continent and its interior began. Numerous studies were carried out by English expeditions led by Ernest Shackleton (he wrote the book “The Most Terrible Campaign” about them). In 1911-1912, a real race to conquer the South Pole began between the expeditions of the Norwegian explorer Roald Amundsen and the Englishman Robert Scott. Amundsen was the first to reach the South Pole; a month after him, Robert Scott's party arrived at the cherished point and died on the way back.

From the middle of the 20th century, the study of Antarctica began on an industrial basis. On the continent, various countries are creating numerous permanent bases that conduct meteorological, glaciological and geological research all year round. On December 14, 1958, the third Soviet Antarctic expedition, led by Evgeniy Tolstikov, reached the South Pole of Inaccessibility and founded a temporary station there, the Pole of Inaccessibility.

Population

Due to the severity of the climate, Antarctica has no permanent population. However, there are scientific stations located there. The temporary population of Antarctica ranges from 4,000 people in summer (about 150 Russians) to 1,000 people in winter (about 100 Russians).

Antarctica has been assigned the top-level Internet domain .aq and the telephone prefix +672.

Antarctica (Greek ἀνταρκτικός - the opposite of the Arctic) is a continent located in the very south of the Earth, the center of Antarctica approximately coincides with the southern geographic pole. Antarctica is washed by the waters of the Southern Ocean.

The continent's area is about 14,107,000 km² (of which ice shelves - 930,000 km², islands - 75,500 km²).

Antarctica is also called the part of the world consisting of the mainland of Antarctica and adjacent islands.

Discovery of the continent of Antarctica

Antarctica was discovered on January 16 (28), 1820 by a Russian expedition led by Thaddeus Bellingshausen and Mikhail Lazarev, who approached it at the point 69°21′ S on the sloops “Vostok” and “Mirny”. w. 2°14′ W d. (G) (O) (region of the modern Bellingshausen ice shelf). Previous existence southern continent(lat. Terra Australis) was stated hypothetically, it was often combined with South America (for example, on the map compiled by Piri Reis in 1513) and Australia. However, it was the expedition of Bellingshausen and Lazarev in the south polar seas, circumnavigating the Antarctic ice around the world, that confirmed the existence of a sixth continent.

The first to enter the continent were probably the crew of the American ship Cecilia on February 7, 1821. The exact location of the landing is unknown, but it is believed to have occurred at Hughes Bay (64°13′S 61°20′W (G)(O)). This statement of landing on the continent is one of the earliest. The most accurate is the statement about the landing on the mainland (Davis Coast) from the Norwegian businessman Henrik Johann Bull, dating back to 1895.

Geographical division

The territory of Antarctica is divided into geographical areas and regions discovered years earlier by various travelers. The area being explored and named after the discoverer (or others) is called "land".

Official list of lands of Antarctica:

Queen Maud Land
Wilkes Land
Victoria Land
Mary Byrd Land
Ellsworth Land
Kotsa Land
Enderby Land

The northernmost point of the continent is Prime Head.

Antarctica is the highest continent on Earth; the average height of the continent's surface above sea level is more than 2000 m, and in the center of the continent it reaches 4000 meters. Most of this height is made up of the permanent ice cover of the continent, under which the continental relief is hidden and only 0.3% (about 40 thousand km²) of its area is free from ice - mainly in West Antarctica and the Transantarctic Mountains: islands, sections of the coast, etc. n. “dry valleys” and individual ridges and mountain peaks (nunataks) rising above the icy surface. The Transantarctic Mountains, crossing almost the entire continent, divide Antarctica into two parts - West Antarctica and East Antarctica, which have different origins and geological structures. In the east there is a high (highest elevation of the ice surface ~4100 m above sea level) ice-covered plateau. The western part consists of a group of mountainous islands connected by ice. On the Pacific coast are the Antarctic Andes, whose altitude exceeds 4000 m; the highest point on the continent is 5140 m above sea level - the Vinson Massif in the Ellsworth Mountains. In West Antarctica there is also the deepest depression of the continent - the Bentley Basin, probably of rift origin. The depth of the ice-filled Bentley Trench reaches 2555 m below sea level.

Research using modern methods has made it possible to learn more about the subglacial topography of the southern continent. As a result of the research, it turned out that about a third of the continent lies below the level of the world ocean; research also showed the presence of mountain ranges and massifs.

The western part of the continent has complex terrain and large elevation changes. Here are the highest mountain (Vinson Mountain 5140 m) and the deepest depression (Bentley Trough −2555 m) in Antarctica. The Antarctic Peninsula is a continuation of the South American Andes, which stretch towards the south pole, slightly deviating from it to the western sector.

The eastern part of the continent has a predominantly smooth topography, with individual plateaus and mountain ranges up to 3-4 km high. In contrast to the western part, which is composed of young Cenozoic rocks, the eastern part is a protrusion of the crystalline foundation of a platform that was previously part of Gondwana.

The continent has relatively low volcanic activity. The largest volcano is Mount Erebus on Ross Island in the sea of the same name.

Subglacial studies conducted by NASA have discovered a crater of asteroid origin in Antarctica. The diameter of the crater is 482 km. The crater was formed when an asteroid with a diameter of about 48 kilometers (larger than Eros) fell to Earth, approximately 250 million years ago, during the Permian-Triassic time. The dust raised during the fall and explosion of the asteroid led to centuries-long cooling and the death of most of the flora and fauna of that era. This crater is currently considered the largest on Earth.

If the glaciers completely melt, the area of Antarctica will be reduced by a third: Western Antarctica will turn into an archipelago, and eastern Antarctica will remain a continent. According to other sources, the whole of Antarctica will turn into an archipelago.

The Antarctic ice sheet is the largest on our planet and is approximately 10 times larger in area than the nearest largest, the Greenland Ice Sheet. It contains ~30 million km³ of ice, that is, 90% of all land ice. Due to the severity of the ice, as studies by geophysicists show, the continent subsided by an average of 0.5 km, as indicated by its relatively deep shelf. The ice sheet in Antarctica contains about 80% of all fresh water on the planet; if it melted completely, sea levels would rise by almost 60 meters (for comparison, if the Greenland ice sheet were to melt, sea levels would rise by only 8 meters).

The ice sheet has a dome shape with increasing surface steepness towards the coast, where it is framed in many places by ice shelves. The average thickness of the ice layer is 2500-2800 m, reaching a maximum value in some areas of East Antarctica - 4800 m. The accumulation of ice on the ice sheet leads, as in the case of other glaciers, to the flow of ice into the ablation (destruction) zone, which acts as continental coast; the ice breaks off in the form of icebergs. The annual volume of ablation is estimated at 2500 km³.

A special feature of Antarctica is the large area of ice shelves (low (blue) areas of West Antarctica), which accounts for ~10% of the area above sea level; these glaciers are sources of icebergs of record sizes, significantly exceeding the size of the icebergs of the outlet glaciers of Greenland; for example, in 2000, the largest currently known iceberg (2005), B-15, with an area of over 10 thousand km², broke off from the Ross Ice Shelf. In winter (summer in the Northern Hemisphere), the area of sea ice around Antarctica increases to 18 million km², and in summer it decreases to 3-4 million km².

The age of the ice sheet in the upper part can be determined from annual layers consisting of winter and summer deposits, as well as from marker horizons, carrying information about global events (for example, volcanic eruptions). But at great depths, to determine the age, numerical modeling of ice spreading is used, which is based on knowledge of the relief, temperature, rate of snow accumulation, etc.

According to Academician Vladimir Mikhailovich Kotlyakov, the continental ice sheet formed no later than 5 million years ago, but, more likely, 30-35 million years ago. This was apparently facilitated by the rupture of the bridge connecting South America and the Antarctic Peninsula, which led, in turn, to the formation of the Antarctic circumpolar current (Western Wind Current) and the isolation of the Antarctic waters from the World Ocean - these waters make up the so-called Southern Ocean.

Geological structure

Geological structure of East Antarctica

East Antarctica is an ancient Precambrian continental platform (craton) similar to those of India, Brazil, Africa and Australia. All these cratons were formed during the breakup of the supercontinent Gondwana. The age of the crystalline basement rocks is 2.5-2.8 billion years, the oldest rocks of Enderby Land are more than 3 billion years old.

The foundation is covered by a younger sedimentary cover, formed 350-190 million years ago, mainly of marine origin. In layers with an age of 320-280 million years, there are glacial deposits, but younger ones contain fossil remains of plants and animals, including ichthyosaurs, which indicates a strong difference in the climate of that time from the modern one. Findings of heat-loving reptiles and fern flora were made by the first explorers of Antarctica and served as one of the strongest evidence of large-scale horizontal plate movements, confirming the concept of plate tectonics.

Seismic activity. Volcanism

Antarctica is a tectonically calm continent with little seismic activity; manifestations of volcanism are concentrated in West Antarctica and are associated with the Antarctic Peninsula, which arose during the Andean period of mountain building. Some of the volcanoes, especially island volcanoes, have erupted in the last 200 years. The most active volcano in Antarctica is Erebus. It is called “the volcano guarding the path to the South Pole.”

Climate

Antarctica has an extremely harsh cold climate. In East Antarctica, at the Soviet Antarctic station Vostok, on July 21, 1983, the lowest air temperature on Earth in the entire history of meteorological measurements was recorded: 89.2 degrees below zero. The area is considered the Earth's pole of cold. Average temperatures in the winter months (June, July, August) are from −60 to −75 °C, in the summer months (December, January, February) from −30 to −50 °C; on the coast in winter from −8 to −35 °C, in summer 0-5 °C.

Another feature of the meteorology of East Antarctica is the katabatic winds caused by its dome-shaped topography. These stable southerly winds arise on fairly steep slopes of the ice sheet due to the cooling of the air layer near the ice surface, the density of the near-surface layer increases, and it flows down the slope under the influence of gravity. The thickness of the air flow layer is usually 200-300 m; Due to the large amount of ice dust carried by the wind, horizontal visibility in such winds is very low. The strength of the katabatic wind is proportional to the steepness of the slope and highest values reaches in coastal areas with a high slope towards the sea. The katabatic winds reach their maximum strength in the Antarctic winter - from April to November they blow almost continuously around the clock, from November to March - at night or when the Sun is low above the horizon. In summer, during the daytime, due to the heating of the surface layer of air by the sun, katabatic winds along the coast cease.

Data on temperature changes from 1981 to 2007 show that the temperature background in Antarctica changed unevenly. For West Antarctica as a whole, an increase in temperature has been observed, while for East Antarctica no warming has been detected, and even some decline has been noted. It is unlikely that the melting of Antarctica's glaciers will increase significantly in the 21st century. On the contrary, as temperatures rise, the amount of snow falling on the Antarctic ice sheet is expected to increase. However, due to warming, more intense destruction of ice shelves and acceleration of the movement of Antarctica's outlet glaciers, throwing ice into the World Ocean, is possible.

Due to the fact that not only the average annual temperature, but also in most areas even summer temperatures in Antarctica do not exceed zero degrees, precipitation there falls only in the form of snow (rain is an extremely rare occurrence). It forms an ice sheet (snow is compressed under its own weight) more than 1,700 m thick, in some places reaching 4,300 m. About 80% of all fresh water on Earth is concentrated in Antarctic ice. However, there are lakes in Antarctica, and in summer time and rivers. The rivers are fed by glaciers. Thanks to intensive solar radiation, due to the exceptional transparency of the air, the melting of glaciers occurs even with insignificant negative temperature air. On the surface of the glacier, often at a considerable distance from the coast, streams of melt water form. The most intense melting occurs near oases, next to rocky soil heated in the sun. Since all streams are fed by the melting of the glacier, their water and level regimes are completely determined by the course of air temperature and solar radiation. The highest flows in them are observed during the hours of the highest air temperatures, that is, in the afternoon, and the lowest - at night, and often at this time the riverbeds dry out completely. As a rule, glacier streams and rivers have very winding channels and connect numerous glacier lakes. Open channels usually end before reaching the sea or lake, and the watercourse makes its way further under the ice or in the thickness of the glacier, like underground rivers in karst areas.

With the onset of autumn frosts, the flow stops, and deep channels with steep banks are covered with snow or blocked by snow bridges. Sometimes almost constant snow drifts and frequent snowstorms block the beds of streams even before the flow stops, and then the streams flow in ice tunnels, completely invisible from the surface. Like cracks in glaciers, they are dangerous, as heavy vehicles can fall into them. If the snow bridge is not strong enough, it may collapse under the weight of a person. The rivers of Antarctic oases, flowing through the ground, usually do not exceed a length of several kilometers. The largest is the river. Onyx, more than 20 km long. Rivers exist only in summer.

Antarctic lakes are no less unique. Sometimes they are classified as a special, Antarctic type. They are located in oases or dry valleys and are almost always covered with a thick layer of ice. However, in the summer, a strip of open water several tens of meters wide forms along the banks and at the mouths of temporary watercourses. Often, lakes are stratified. At the bottom there is a layer of water with elevated temperature and salinity, as, for example, in Lake Vanda (English) Russian. In some small endorheic lakes, the salt concentration is significantly increased and they can be completely ice-free. For example, lake Don Juan, with a high concentration of calcium chloride in its waters, freezes only when very low temperatures. Antarctic lakes are small, only some of them are larger than 10 km² (Lake Vanda, Lake Figurnoe). The largest of the Antarctic lakes is Lake Figurnoye in the Banger oasis. Curiously meandering among the hills, it stretches for 20 kilometers. Its area is 14.7 km², and its depth exceeds 130 meters. The deepest is Lake Radok, its depth reaches 362 m.

There are lakes on the coast of Antarctica that were formed as a result of the backwater of snowfields or small glaciers. Water in such lakes sometimes accumulates for several years until its level rises to the upper edge of the natural dam. Then excess water begins to flow out of the lake. A channel is formed, which quickly deepens, and the water flow increases. As the channel deepens, the water level in the lake drops and it shrinks in size. In winter, the dry riverbed is covered with snow, which gradually becomes compacted, and the natural dam is restored. In the next summer season, the lake begins to fill with meltwater again. Several years pass until the lake is filled and its waters again break into the sea.

Comparing Antarctica with other continents, it can be noted that there are absolutely no wetlands on the South Polar Continent. However, in the coastal strip there are peculiar glacial “swamps”. They form in summer in depressions filled with snow and firn. Melt water flowing into these depressions moistens the snow and firn, resulting in a snow-water porridge, viscous, like ordinary swamps. The depth of such “swamps” is most often insignificant - no more than a meter. On top they are covered with a thin ice crust. Like real swamps, they are sometimes impassable even for tracked vehicles: a tractor or all-terrain vehicle that gets stuck in such a place, stuck in a snow-water porridge, without outside help won't get out.

In the 1990s, Russian scientists discovered the subglacial non-freezing Lake Vostok - the largest of the Antarctic lakes, having a length of 250 km and a width of 50 km; the lake holds about 5,400 thousand km³ of water.

In total, as of 2007, more than 140 subglacial lakes were discovered in Antarctica.

As a result of global warming, tundra began to actively form on the Antarctic Peninsula. Scientists predict that in 100 years the first trees may appear in Antarctica.

The oasis on the Antarctic Peninsula covers an area of 400 km², the total area of oases is 10 thousand km², and the area is not busy with ice areas (including snowless rocks) is 30-40 thousand km².

Plants include flowering plants, ferns (on the Antarctic Peninsula), lichens, fungi, bacteria, and algae (in oases). Seals and penguins live on the coast.

Antarctic animals are completely dependent on the coastal ecosystem of the Southern Ocean: due to the paucity of vegetation, all food chains of any significance in coastal ecosystems begin in the waters surrounding Antarctica. Antarctic waters are particularly rich in zooplankton, primarily krill. Krill directly or indirectly form the basis of the food chain of many species of fish, cetaceans, squid, seals, penguins and other animals; There are no completely land mammals in Antarctica; invertebrates are represented by approximately 70 species of arthropods (insects and arachnids) and nematodes living in soils.

Terrestrial animals include seals (Weddell, crabeater seals, leopard seals, Ross seals, elephant seals) and birds (several species of petrels (Antarctic, snowy), two species of skuas, Arctic tern, Adélie penguins and emperor penguins).

Nunataks are characterized only by bacteria, algae, lichens and severely suppressed mosses; only skuas, following people, occasionally fly onto the ice sheet.

There is an assumption about the presence in subglacial lakes of Antarctica, such as Lake Vostok, of extremely oligotrophic ecosystems, practically isolated from the outside world.

In 1994, scientists reported a rapid increase in the number of plants in Antarctica, which seems to confirm the hypothesis of global warming of the planet.

The Antarctic Peninsula and its adjacent islands have the most favorable climatic conditions on the mainland. It is here that two species of flowering plants found in the region grow - Antarctic meadowsweet and Quito colobanthus.

Man and Antarctica

In preparation for the International Geophysical Year, about 60 bases and stations belonging to 11 states were founded on the coast, ice sheet and islands (including Soviet - Mirny Observatory, Oasis, Pionerskaya, Vostok-1, Komsomolskaya and Vostok stations, American - Amudsen -Scott at the South Pole, Baird, Hulett, Wilkes and McMurdo).

Since the late 1950s. Oceanological work is being carried out in the seas washing the continent, and regular geophysical research is being carried out at stationary continental stations; Expeditions into the continent are also being undertaken. Soviet scientists carried out a sleigh-and-tractor trip to the Geomagnetic Pole (1957), the Pole of Relative Inaccessibility (1958), and the South Pole (1959). American researchers traveled on all-terrain vehicles from Little America station to Baird station and further to Sentinel station (1957), in 1958-1959 from Ellsworth station through the Dufeka massif to Baird station; English and New Zealand scientists on tractors in 1957-1958 crossed Antarctica through the South Pole from the Wedell Sea to the Ross Sea. Australian, Belgian and French scientists also worked in the interior of Antarctica. Concluded in 1959 international treaty about Antarctica, which contributed to the development of cooperation in the study of the ice continent.

History of the study of the continent

The first ship to cross the Antarctic Circle belonged to the Dutch; it was commanded by Dirk Geeritz, who sailed in the squadron of Jacob Magyu. In 1559, in the Strait of Magellan, Geeritz's ship lost sight of the squadron after a storm and went south. When it dropped to 64° S. sh., high ground was discovered there. In 1675 La Roche discovered South Georgia; Bouvet Island was discovered in 1739; In 1772, in the Indian Ocean, Yves-Joseph Kerglen, a French naval officer, discovered an island named after him.

Almost simultaneously with Kerglen’s voyage, James Cook set off from England on his first voyage to the Southern Hemisphere, and already in January 1773, his ships “Adventure” and “Resolution” crossed the Antarctic Circle at the meridian 37°33′E. d. After a difficult struggle with ice, he reached 67°15′ S. sh., where he was forced to turn north. In December 1773, Cook again set off for the southern ocean, crossing it on December 8 and at parallel 67°5′ S. w. was covered in ice. Having freed himself, Cook went further south and at the end of January 1774 reached 71°15′ S. sh., southwest of Tierra del Fuego. Here an impenetrable wall of ice prevented him from going further. Cook was one of the first to reach the south polar seas and, having encountered solid ice in several places, declared that it could not be penetrated further. They believed him and did not undertake polar expeditions for 45 years.

First geographical discovery lands south of 60° S. (modern "political Antarctica", governed by the Antarctic Treaty system) was accomplished by the English merchant William Smith, who stumbled upon Livingston Island, South Shetland Islands, on February 19, 1819.

In 1819, Russian sailors F.F. Bellingshausen and M.P. Lazarev, on the sloops of war "Vostok" and "Mirny", visited South Georgia and tried to penetrate into the depths of the Arctic Ocean. For the first time, on January 28, 1820, almost on the Greenwich meridian, they reached 69°21′ S. w. and discovered modern Antarctica itself; then, leaving the Arctic Circle, Bellingshausen walked along it east to 19° east. d., where he crossed it again and in February 1820 again reached almost the same latitude (69°6′). Further east, he rose only to the 62° parallel and continued his path along the outskirts of the floating ice. Then, on the meridian of the Balleny Islands, Bellingshausen reached 64°55′, and in December 1820 reached 161°w. d., passed the Antarctic Circle and reached 67°15′ S. latitude, and in January 1821 reached 69°53′ S. w. Almost at the 81° meridian, he discovered the high coast of the island of Peter I, and having gone further east, inside the Antarctic Circle, the coast of Alexander I Land. Thus, Bellingshausen was the first to complete a complete voyage around Antarctica at latitudes from 60° to 70°.

In 1838-1842, the American Charles Wilkes explored a part of Antarctica, named after him Wilkes Land. In 1839-1840, the Frenchman Jules Dumont-D'Urville discovered Adélie Land, and in 1841-1842 the Englishman James Ross discovered the Ross Sea and Victoria Land. The first landing on the shores of Antarctica and the first wintering was made by the Norwegian expedition of Karsten Borchgrevink in 1895.

After this, the study of the coast of the continent and its interior began. Numerous studies were carried out by English expeditions led by Ernest Shackleton (he wrote the book “In the Heart of Antarctica” about them). In 1911-1912, a real race to conquer the South Pole began between the expedition of the Norwegian explorer Roald Amundsen and the expedition of the Englishman Robert Scott. The first to reach the South Pole were Amundsen, Olaf Bjaland, Oscar Wisting, Helmer Hansen and Sverre Hassel; a month after him, Scott's party arrived at the cherished point, but died on the way back.

In the 19th century, several whaling bases existed on the Antarctic Peninsula and surrounding islands. Subsequently, they were all abandoned.

The harsh climate of Antarctica prevents its settlement. Currently, there is no permanent population in Antarctica; there are several dozen scientific stations on which, depending on the season, live from 4,000 people (150 Russian citizens) in the summer and about 1,000 in the winter (about 100 Russian citizens).

In 1978, the first man of Antarctica, Emilio Marcos Palma, was born at the Argentine station Esperanza.

Antarctica has been assigned the top-level Internet domain .aq and the telephone prefix +672.

Status of Antarctica

In accordance with the Antarctic Convention, signed on December 1, 1959 and entered into force on June 23, 1961, Antarctica does not belong to any state. Only scientific activities are permitted.

The deployment of military facilities, as well as the entry of warships and armed vessels south of 60 degrees south latitude are prohibited.

In the 1980s, Antarctica was also declared a nuclear-free zone, which excluded the appearance of nuclear-powered ships in its waters and nuclear power units on the mainland.

Currently, 28 states (with voting rights) and dozens of observer countries are parties to the treaty.

Territorial claims

However, the existence of a treaty does not mean that the states that joined it renounced their territorial claims to the continent and the surrounding area. On the contrary, the territorial claims of some countries are enormous. For example, Norway claims territory ten times larger than its own (including the island of Peter I, discovered by the Bellingshausen-Lazarev expedition). Great Britain declared huge territories as its own. The British intend to extract ore and hydrocarbon resources on the Antarctic shelf. Australia considers almost half of Antarctica its own, into which, however, the “French” Adélie Land is wedged. New Zealand also made territorial claims. Great Britain, Chile and Argentina claim almost the same territory, including the Antarctic Peninsula and the South Shetland Islands. No country has officially made territorial claims to Mary Byrd's land. However, hints about US rights to this territory are contained in unofficial American sources.

The United States and Russia took a special position, declaring that, in principle, they could put forward their territorial claims in Antarctica, although they have not yet done so. Moreover, both states do not recognize the claims of other countries.

The continent of Antarctica today is the only uninhabited and undeveloped continent on Earth. Antarctica has long attracted European powers and the United States, but it began to attract global interest at the end of the 20th century. Antarctica is the last resource reserve for humanity on Earth. After the exhaustion of raw materials on the five inhabited continents, people will develop their resources. However, since Antarctica will remain the only source of resources for countries, the struggle for its resources has already begun, which could result in a fierce military conflict. Geologists have found that the depths of Antarctica contain a significant amount of minerals - iron ore, coal; Traces of ores of copper, nickel, lead, zinc, molybdenum, rock crystal, mica, and graphite were found. In addition, Antarctica contains about 80% of the world's fresh water, a shortage of which is already felt in many countries.

Currently, observations are being made of climatic and meteorological processes on the continent, which, like the Gulf Stream in the Northern Hemisphere, is a climate-forming factor for the entire Earth. In Antarctica, the effects of space and the processes occurring in the earth's crust are also studied.

The study of the ice sheet brings serious scientific results, informing us about the climate of the Earth hundreds, thousands, hundreds of thousands of years ago. The Antarctic ice sheet contains data on the climate and composition of the atmosphere over the past hundred thousand years. By chemical composition different layers of ice determine the level solar activity over the past several centuries.

Microorganisms have been discovered in Antarctica that may be of scientific value and will allow for better study of these life forms.

Many Antarctic bases, especially Russian ones, located around the continent's perimeter, provide ideal opportunities for monitoring seismological activity throughout the planet. Antarctic bases are also testing technologies and equipment that are planned to be used in the future for the exploration, development and colonization of other planets in the solar system.

Russia in Antarctica

In total, there are about 45 year-round scientific stations in Antarctica. Currently, Russia has seven operating stations and one field base in Antarctica.

Permanently active:

Bellingshausen
Peaceful
Novolazarevskaya
East
Progress
Marine squad
Leningradskaya (Reopened in 2008)
Russian (Reactivated in 2008)

Canned:

Youth
Druzhnaya-4

No longer existing:

Pionerskaya
Komsomolskaya
Soviet
Vostok-1
Lazarev
Pole of inaccessibility
Oasis (transferred to Poland in 1959)

Orthodox Church

The first Orthodox church in Antarctica was built on Waterloo Island (South Shetland Islands) near the Russian Bellingshausen station with the blessing of His Holiness Patriarch Alexia II. They collected it in Altai, and then transported it to the icy continent on the scientific vessel Akademik Vavilov. The fifteen-meter high temple was built from cedar and larch. It can accommodate up to 30 people.

The temple was consecrated in the name of the Holy Trinity on February 15, 2004 by the abbot of the Holy Trinity Lavra of St. Sergius, Bishop Feognost of Sergiev Posad, in the presence of numerous clergy, pilgrims and sponsors, who arrived on a special flight from the nearest city, Chilean Punta Arenas. Now the temple is Patriarchal Metochion Trinity-Sergius Lavra.

The Church of the Holy Trinity is considered the southernmost Orthodox church in the world. To the south there is only the chapel of St. John of Rila at the Bulgarian station St. Kliment Ohridski and the chapel of St. Prince Equal to the Apostles Vladimir at the Ukrainian station Academician Vernadsky.

On January 29, 2007, the first wedding in Antarctica took place in this temple (the daughter of a polar explorer, Russian Angelina Zhuldybina and Chilean Eduardo Aliaga Ilabac, working at the Chilean Antarctic base).

Interesting facts

The average surface elevation of Antarctica is the highest of any continent.
In addition to the pole of cold, Antarctica contains points of the lowest relative air humidity, the strongest and longest winds, and the most intense solar radiation.
Although Antarctica is not the territory of any state, enthusiasts from the United States issue the unofficial currency of the continent - the “Antarctic dollar”.

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The ice of the Arctic and Antarctic is not at all eternal. Nowadays, due to the impending global warming caused by the environmental crisis of thermal and chemical pollution of the atmosphere, the mighty shields of frost-bound water are melting. This threatens a great disaster for a vast territory, which includes low-lying coastal lands of different countries, primarily European ones (for example, Holland).

But since the ice sheet of the poles is capable of disappearing, it means that it once arose during the development of the planet. "White caps" appeared - a very long time ago - within some limited interval of the geological history of the Earth. Glaciers cannot be considered an integral property of our planet as a cosmic body.

Comprehensive (geophysical, climatological, glaciological and geological) studies of the southern continent and many other areas of the planet have convincingly proven that the ice cover of Antarctica arose relatively recently. Similar conclusions were drawn regarding the Arctic.

Firstly, data from glaciology (the science of glaciers) indicate a gradual increase in ice cover over the past millennia. For example, the glacier covering the Ross Sea was much smaller in area just 5,000 years ago than it is now. It is assumed that at that time it occupied only half of the current territory it covers. Until now, according to some experts, the slow freezing of this gigantic tongue of ice continues.

Drilling wells in the thickness of continental ice has yielded unexpected results. The cores clearly showed how successive layers of ice froze over the last 10-15 thousand years. Spores of bacteria and plant pollen were found in different layers. Consequently, the ice sheet of the continent grew and actively developed during the last millennia. This process was influenced by climatic and other factors, since the rate of formation of ice layers varies.

Some of those found frozen in the thickness Antarctic ice bacteria (up to 12 thousand years old) were revived and studied under a microscope. At the same time, a study of air bubbles immured in these huge layers of frozen water was organized. Work in this area has not been completed, but it is clear that scientists have evidence of the composition of the atmosphere in the distant past.

Geological studies have confirmed that glaciation is a short-term natural phenomenon. The oldest global glaciation discovered by scientists occurred over 2000 million years ago. Then these colossal catastrophes were repeated quite often. The Ordovician glaciation occurs in an era 440 million years removed from our time. During this climate cataclysm, a great many marine invertebrates died. There were no other animals at that time. They appeared much later to become victims of the next freezing attacks that covered almost all continents.

The last glaciation, apparently, has not yet ended, but has retreated for a while. The great retreat of the ice occurred about 10 thousand years ago. Since then, powerful ice shells that once covered Europe, large parts of Asia and North America, remained only in Antarctica, on the Arctic islands and on top of the waters of the Arctic Ocean. Modern humanity lives during the so-called period interglacial period, which should be replaced by a new advance of ice. Unless, of course, they melt completely first.

Geologists have received a lot of interesting facts about Antarctica itself. The Great White Continent apparently was once completely ice-free and had an even and warm climate. 2 million years ago, dense forests, like taiga, grew on its coasts. In ice-free spaces, it is possible to systematically find fossils from a later, Middle Tertiary time - imprints of leaves and twigs of ancient heat-loving plants.

Then, over 10 million years ago, despite the cooling that began on the continent, the local expanses were occupied by vast groves of laurels, chestnut oaks, cherry laurel trees, beech trees and other subtropical plants. It can be assumed that these groves were inhabited by animals characteristic of that time - mastodons, saber-tooths, hipparions, etc. But much more striking are the ancient finds in Antarctica.

In the central part of Antarctica, for example, the skeleton of the fossil lizard Lystrosaurus was found - not far from the South Pole, in outcrops rocks. Large reptile two meters long, it had an unusually terrible appearance. The age of the find is 230 million years.

Lystrosaurs were, like other animal lizards, typical representatives of heat-loving fauna. They inhabited hot, swampy lowlands, abundantly overgrown with vegetation. Scientists have discovered an entire belt in the geological deposits of South Africa, overflowing with the bones of these animals, which is called the Lystrosaurus Zone. Something similar was found on the South American continent, as well as in India. It is obvious that in the early Triassic period, 230 million years ago, the climate of Antarctica, Hindustan, South Africa and South America was similar, since the same animals could live there.

Scientists are looking for an answer to the riddle of the birth of glaciers - what global processes, invisible in our interglacial era, 10 thousand years ago bound a huge part of the land and the World Ocean under a shell of solidified water? What causes such drastic climate change. None of the hypotheses is convincing enough to become generally accepted. Nevertheless, it is worth remembering the most popular ones. Among the hypotheses, three can be distinguished, conventionally called cosmic, planetary-climatic and geophysical. Each of them gives preference to a certain group of factors or one decisive factor that served as the root cause for the cataclysm.

The cosmic hypothesis is based on data from geological surveys and astrophysical observations. When establishing the age of moraines and other rocks deposited by ancient glaciers, it turned out that climatic catastrophes occurred with strict frequency. The ground froze in a time interval that seemed specially designated for this. Each great cold snap is separated from the others by a period of approximately 200 million years. This means that after every 200 million years of dominance warm climate A long winter reigned on the planet, and powerful ice caps formed. Climatologists turned to materials accumulated by astrophysicists: what could be responsible for such an incredibly long time between several iterative (regularly occurring) events in the atmosphere and hydrosphere of a space object? Perhaps with cosmic events comparable in scale and time frame?

Calculations by astrophysicists call such an event the revolution of the Sun around the galactic core. The dimensions of the Galaxy are extremely large. The diameter of this cosmic disk reaches a size of approximately 1000 trillion km. The Sun is located at a distance of 300 trillion km from the galactic core, so the full revolution of our star around the center of the system takes such a colossal period of time. Apparently, on its way, the Solar System crosses some area in the Galaxy, under the influence of which another glaciation occurs on Earth.

This hypothesis is not accepted in the scientific world, although it seems convincing to many. However, scientists do not have facts on the basis of which it could be proven or at least convincingly confirmed. There are no facts confirming the galactic influence on the million-year fluctuations in the planet’s climate; there is nothing except a strange coincidence of numbers. Astrophysicists have not found a mysterious region in the Galaxy where the Earth begins to freeze. That species was not found either external influence, due to which something like this could happen. Some suggest a decrease in solar activity. It seems that the “cold zone” has reduced the flow intensity solar radiation, and as a result, the Earth began to receive less heat. But these are just assumptions.

Supporters of the original version came up with a name for the imaginary processes occurring in the stellar system. The complete revolution of the solar system around the galactic core was called the galactic year, and the short interval during which the Earth remains in troubled " cold zone" - space winter.

Some supporters of the extraterrestrial origin of glaciers are looking for climate change factors not in the distant Galaxy, but inside the Solar System. For the first time such an assumption was made in 1920, its author was the Yugoslav scientist M. Milankovic. He took into account the inclination of the earth to the plane of the ecliptic and the inclination of the ecliptic itself to the solar axis. According to Milankovitch, the answer to the great glaciations should be sought here.

The fact is that depending on these inclinations the amount of radiant energy of the Sun reaching earth's surface. In particular, different latitudes receive different numbers of rays. The relative position of the axes of the Sun and the Earth, changing over time, causes fluctuations in the amount of solar radiation in different regions of the planet and, under certain circumstances, leads the fluctuations to the stage of alternating warm and cold phases.

In the 90s XX century this hypothesis has been thoroughly tested using computer models. Numerous external influences on the location of the planet relative to the Sun - the Earth’s orbit slowly evolved under the influence of the gravitational fields of neighboring planets, the trajectory of the Earth’s movement was gradually transformed.

French geophysicist A. Berger compared the obtained figures with geological data, with the results of radioisotope analysis of marine sediments, showing temperature changes over millions of years. Temperature fluctuations in ocean waters completely coincided with the dynamics of the process of transforming the earth's orbit. Consequently, the cosmic factor could well have provoked the onset of climate cooling and global glaciation.

At the moment, it cannot be said that the Milankovitch conjecture has been proven. First, it requires additional long-term checks. Secondly, scientists tend to be of the opinion that global processes could not be caused by the action of only one factor, especially if it is external. Most likely, there was synchronization of the actions of various natural phenomena, and the decisive role in this amount belonged to the Earth’s own elements.

The planetary-climate hypothesis is based precisely on this position. The planet is a huge climatic machine, which with its rotation directs the movement of air currents, cyclones and typhoons. The inclined position relative to the plane of the ecliptic causes non-uniform heating of its surface. In a sense, the planet itself is a powerful climate control device. And her internal forces are the reasons for his metamorphosis.

These internal forces include mantle currents, or so-called. convection currents in layers of molten magmatic matter that compose the mantle layer underlying the earth's crust. The movements of these currents from the core of the planet to the surface give rise to earthquakes and volcanic eruptions, and mountain-building processes. These same currents cause the appearance of deep splits in the earth's crust, called rift zones (valleys), or rifts.

Rift valleys are numerous on the ocean floor, where the crust is very thin and easily breaks through the pressure of convection currents. Volcanic activity is extremely high in these areas. Here, mantle material is constantly pouring out from the depths. According to the planetary-climate hypothesis, it is magma outpourings that play a decisive role in the oscillatory process of historical transformation of the weather regime.

Rift faults on the ocean floor, during periods of greatest activity, release enough heat to cause intense evaporation of seawater. This causes a lot of moisture to accumulate in the atmosphere, which then falls as precipitation onto the Earth’s surface. In cold latitudes, precipitation falls in the form of snow. But since their fall is too intense and the quantity is large, the snow cover becomes more powerful than usual.

The snow cap melts extremely slowly; for a long time, the influx of precipitation exceeds its outflow - melting. As a result, it begins to grow and transforms into a glacier. The planet's climate is also gradually changing as a stable area of non-melting ice forms. After some time, the glacier begins to expand, since the dynamic system of uneven inflow and outflow cannot remain in balance, and the ice increases to incredible sizes and binds almost the entire planet.

However, the maximum of glaciation simultaneously becomes the beginning of its degradation. Having reached a critical point, an extremum, ice growth stops, encountering stubborn resistance from other natural factors. The dynamics became reversed; the rise gave way to a decline. However, the victory of “summer” over “winter” does not come immediately. Initially, a protracted “spring” begins for several thousand years. This is a change of short bouts of glaciation with warm interglacials.

Earth civilization was formed in the era of the so-called. Holocene interglacial. It began about 10,000 years ago, and will end, according to mathematical models, at the end of the 3rd millennium AD, i.e. around 3000. From this moment the next cold snap will begin, which will reach its apogee after 8000 of our chronological calendar.

The main argument of the planetary-climate hypothesis is the fact of periodic changes in tectonic activity in rift valleys. Convection currents in the bowels of the Earth excite the earth's crust with different strengths, this leads to the existence of such eras. Geologists have materials that convincingly prove that climatic fluctuations are chronologically linked to periods of greatest tectonic activity of the subsoil.

Rock deposits show that the next climate cooling is accompanied by significant movements of powerful blocks. earth's crust, which were accompanied by the appearance of new faults and the rapid release of hot magma from both new and old rifts. However, the same argument is used by supporters of other hypotheses to confirm their correctness.

These hypotheses can be considered as variations of a single geophysical hypothesis, since it is based on data about the geophysics of the planet, namely, it relies entirely on paleogeography and tectonics in its calculations. Tectonics studies the geology and physics of the process of movement of crustal blocks, and paleogeography studies the consequences of such movement.

As a result of multimillion-year displacements of colossal masses of solid matter on the earth's surface, the outlines of the continents, as well as the topography, changed significantly. The fact that thick layers of marine sediments or bottom silts are found on land directly indicates movements of crustal blocks, accompanied by its subsidence or uplift in this region. For example, the Moscow region is composed of large quantities limestones abounding in the remains of crinoids and corals, as well as clayey rocks containing mother-of-pearl shells of ammonites. It follows from this that the territory of Moscow and its environs was flooded at least twice sea waters- 300 and 180 million years ago.

Each time, as a result of the displacement of huge blocks of the crust, either a lowering or raising of a certain section of it occurred. In case of subsidence, the continent was invaded ocean waters, there was an advance of the seas, transgression. As the seas rose, they retreated (regression), the land surface grew, and often mountain ranges rose in place of the former salt basin.

The ocean is a powerful regulator and even generator of the Earth's climate due to its colossal heat capacity and other unique physical and chemical properties. This water reservoir controls the most important air flows, air composition, precipitation and temperature patterns over vast land areas. Naturally, an increase or decrease in its surface area affects the nature of global climate processes.

Each transgression significantly increased the area of salt waters, while regression of the seas significantly reduced this area. Accordingly, climate fluctuations occurred. Scientists have found that periodic planetary cooling approximately coincided in time with periods of regression, while the advance of seas onto land was invariably accompanied by climate warming. It would seem that another mechanism of global glaciations has been found, which is perhaps the most important, if not exclusive. However, there is another climate-forming factor that accompanies tectonic movements - mountain building.

The advance and retreat of ocean waters passively accompanied the growth or destruction of mountain ranges. The earth's crust, under the influence of convection currents, wrinkled into chains of the highest peaks here and there. Therefore, an exclusive role in long-period climatic fluctuations should still be given to the process of mountain building (orogenesis). Not only the surface area of the ocean, but also the direction of air flows depended on it.

If a mountain range disappeared or a new one appeared, then the movement of large air masses changed dramatically. Following this, the long-term weather regime in the area was transformed. Thus, as a result of mountain building throughout the planet, local climates radically changed, which led to a general degeneration of the Earth’s climate. As a result, the emerging trend towards global cooling only gained momentum.

The last glaciation is tied to the era of the Alpine mountain building that is ending before our eyes. The result of this orogeny was the Caucasus, the Himalayas, the Pamirs and many other highest mountain systems planets. The eruptions of volcanoes Santorini, Vesuvius, Bezymianny and others were provoked by this very process. We can say that today this hypothesis dominates modern science, although not fully proven.

The hypothesis received an unexpected development, and in application to the climatology of Antarctica. The ice continent acquired its current appearance entirely due to tectonics, but the decisive role was played neither by regression nor by changes in air currents (these factors are considered secondary). The main influencing factor should be called water cooling. Nature froze Atlantis in exactly the same way as a person cools a nuclear reactor.

The “nuclear” version of the geophysical hypothesis is based on the theory of continental drift and paleontological finds. Modern scientists do not doubt the existence of movement of continental plates. Since the blocks of the earth's crust are mobile due to mantle convection, this mobility is accompanied by a horizontal displacement of the continents themselves. They crawl slowly, at a speed of 1-2 cm per year, along the molten mantle layer.

The relative position of the continents changed over time, which affected the Earth's climate, since air and ocean currents depended on it. Fossilized bones of Lystrosaurus in Antarctica and extremely numerous similar finds in Africa, South America and India confirm the assumption of scientists that once all these southern lands, including Australia, were united into one supercontinent.

The single southern continent of Gondwana existed for over 200 million years: from 240 to 35 million years ago. About 35 million years ago, tectonic movements of the crust finally split it into the current “pieces,” one of which was Antarctica. The split had a negative impact on her climate as she found herself isolated.

Previously, the Antarctic coast was washed by only two cold currents, the effect of which was fully compensated by warm ocean currents coming from Australia, docked with Antarctica. After all the pieces of the supercontinent crawled into different sides and left Antarctica alone in the middle of the ocean, it began to be actively washed by many currents, which over time formed a continuous stream - the so-called. circumpolar current.

It surrounded Antarctica and gained strength as the “fifth ocean” - the southern waters of the Antarctic region - grew and deepened. Every second the current carries more water than all the rivers on the planet, which is not surprising given the average depth " southern ocean", equal to 3 km. The current covers all layers of water to the very bottom, being the greatest climatic barrier in nature. This fantastic barrier absorbs all the heat that is supplied to white continent from outside.

It turned out that a drop in air temperature in the Antarctic region of only 3 °C was sufficient for the barrier to begin to act like a refrigerator. Now the increase in snow and ice cover was inevitable even if the relatively warm regime remained on the continent. The glacier gradually, in the process of growth, displaced heat to the outskirts, where it was absorbed by the circumpolar current.

The very first ice caps on the white continent began to grow 30 million years ago on the Gamburtsev Mountains, today completely hidden under an ice shell. Approximately 25-20 million years ago, glacier tongues descended onto the plains and from that moment the complete glaciation of Antarctica became inevitable. Thus, according to one of the models, the formation of the ice sheet of the last of the open by man continents.

Life in the Arctic is intensifying 5819