Glacial period. How often does an ice age occur on Earth? What did the earth look like during the Ice Age?

The last ice age led to the appearance of the woolly mammoth and a huge increase in the area of ​​glaciers. But it was only one of many that cooled the Earth throughout its 4.5 billion years of history.

So, how often does the planet experience ice ages and when should we expect the next one?

Major periods of glaciation in the history of the planet

The answer to the first question depends on whether you are talking about large glaciations or small ones that occur during these long periods. Throughout history, the Earth has experienced five long periods glaciations, some of which lasted for hundreds of millions of years. In fact, even now the Earth is experiencing a large period of glaciation, and this explains why it has polar ice caps.

The five main ice ages are the Huronian (2.4–2.1 billion years ago), the Cryogenian glaciation (720–635 million years ago), the Andean-Saharan glaciation (450–420 million years ago), and the Late Paleozoic glaciation (335–260 million years ago). million years ago) and Quaternary (2.7 million years ago to the present).

These major periods of glaciation may alternate between smaller ice ages and warm periods (interglacials). At the beginning of the Quaternary glaciation (2.7-1 million years ago), these cold ice ages occurred every 41 thousand years. However, significant ice ages have occurred less frequently over the past 800,000 years—about every 100,000 years.

How does the 100,000 year cycle work?

The ice sheets grow for about 90 thousand years and then begin to melt during the 10 thousand year warm period. Then the process is repeated.

Given that the last ice age ended about 11,700 years ago, perhaps it's time for another one to begin?

Scientists believe we should be experiencing another ice age right now. However, there are two factors associated with the Earth's orbit that influence the formation of warm and cold periods. Considering also how much carbon dioxide we emit into the atmosphere, the next ice age won't start for at least 100,000 years.

What causes an ice age?

The hypothesis put forward by Serbian astronomer Milutin Milanković explains why cycles of glacial and interglacial periods exist on Earth.

As a planet orbits the Sun, the amount of light it receives from it is affected by three factors: its inclination (which ranges from 24.5 to 22.1 degrees on a 41,000-year cycle), its eccentricity (the change in the shape of its orbit around of the Sun, which fluctuates from a near circle to an oval shape) and its wobble (one complete wobble occurs every 19-23 thousand years).

In 1976, a landmark paper in the journal Science presented evidence that these three orbital parameters explained the planet's glacial cycles.

Milankovitch's theory is that orbital cycles are predictable and very consistent in the history of the planet. If the Earth is experiencing an ice age, it will be covered with more or less ice, depending on these orbital cycles. But if the Earth is too warm, no change will occur, at least in terms of increasing amounts of ice.

What can affect the warming of the planet?

The first gas that comes to mind is carbon dioxide. Over the past 800 thousand years, carbon dioxide levels have ranged from 170 to 280 parts per million (meaning that out of 1 million air molecules, 280 are carbon dioxide molecules). A seemingly insignificant difference of 100 parts per million results in glacial and interglacial periods. But carbon dioxide levels are significantly higher today than in past periods of fluctuation. In May 2016, carbon dioxide levels over Antarctica reached 400 parts per million.

The Earth has warmed up this much before. For example, during the time of dinosaurs the air temperature was even higher than it is now. But the problem is that in the modern world it is growing at a record pace because we have released too much carbon dioxide into the atmosphere in a short time. Moreover, given that the rate of emissions is not currently decreasing, we can conclude that the situation is unlikely to change in the near future.

Consequences of warming

The warming caused by this carbon dioxide will have big consequences because even a small increase in the Earth's average temperature can lead to dramatic changes. For example, the Earth was on average only 5 degrees Celsius colder during the last ice age than it is today, but this led to a significant change in regional temperatures, the disappearance of huge parts of flora and fauna, and the emergence of new species.

If global warming causes all the ice sheets of Greenland and Antarctica to melt, sea levels will rise by 60 meters compared to today's levels.

What causes major ice ages?

The factors that caused long periods of glaciation, such as the Quaternary, are not as well understood by scientists. But one idea is that a massive drop in carbon dioxide levels could lead to colder temperatures.

For example, according to the uplift and weathering hypothesis, when plate tectonics causes mountain ranges to grow, new exposed rock appears on the surface. It easily weathers and disintegrates when it ends up in the oceans. Marine organisms use these rocks to create their shells. Over time, stones and shells take carbon dioxide from the atmosphere and its level drops significantly, which leads to a period of glaciation.

Last Ice Age

During this era, 35% of the land was under ice cover (compared to 10% today).

The last ice age was not just a natural disaster. It is impossible to understand the life of planet Earth without taking these periods into account. In the intervals between them (known as interglacial periods), life flourished, but then Once again Ice moved inexorably and brought death, but life did not completely disappear. Every Ice Age was marked by a struggle for survival different types, there were global climate change, and in the last of them a new species appeared, which became (over time) dominant on Earth: it was man.
Ice Ages
Ice ages are geological periods characterized by severe cooling of the Earth, during which vast areas of the earth's surface were covered with ice, high levels of humidity and, naturally, exceptional cold, as well as the coldest known cold. modern science sea ​​level. There is no generally accepted theory regarding the reasons for the onset of the Ice Age, but since the 17th century, a variety of explanations have been proposed. According to the current opinion, this phenomenon was not caused by one reason, but was the result of the influence of three factors.

Changes in the composition of the atmosphere - a different ratio of carbon dioxide (carbon dioxide) and methane - caused a sharp drop in temperature. It's like the opposite of what we now call global warming, but on a much larger scale.

The movements of the continents, caused by cyclic changes in the orbit of the Earth around the Sun, and in addition the change in the angle of inclination of the planet’s axis relative to the Sun, also had an impact.

The land received less solar heat, it cooled, which led to glaciation.
The earth has experienced several ice ages. The largest glaciation occurred 950-600 million years ago during the Precambrian era. Then in the Miocene era - 15 million years ago.

Traces of glaciation that can be observed at the present time represent the legacy of the last two million years and belong to the Quaternary period. This period is best studied by scientists and is divided into four periods: Günz, Mindel (Mindel), Ries (Rise) and Würm. The latter corresponds to the last ice age.

Last Ice Age
The Würm stage of glaciation began approximately 100,000 years ago, peaked after 18 thousand years and began to decline after 8 thousand years. During this time, the thickness of the ice reached 350-400 km and covered a third of the land above sea level, in other words, three times the area than now. Based on the amount of ice that currently covers the planet, we can get some idea of ​​the extent of glaciation during that period: today, glaciers occupy 14.8 million km2, or about 10% of the earth's surface, and during the Ice Age they covered an area of ​​44 .4 million km2, which is 30% of the Earth's surface.

According to assumptions, in northern Canada, ice covered an area of ​​13.3 million km2, while now there is 147.25 km2 under ice. The same difference is noted in Scandinavia: 6.7 million km2 in that period compared to 3,910 km2 today.

The Ice Age occurred simultaneously in both hemispheres, although in the North the ice spread over larger areas. In Europe, the glacier covered most of the British Isles, northern Germany and Poland, and in North America, where the Würm glaciation is called the “Wisconsin Ice Age,” a layer of ice that descended from the North Pole covered all of Canada and spread south of the Great Lakes. Like the lakes in Patagonia and the Alps, they were formed on the site of depressions left after the melting of the ice mass.

The sea level dropped by almost 120 m, as a result of which large areas were exposed that are currently covered sea ​​water. The significance of this fact is enormous, since large-scale migrations of humans and animals became possible: hominids were able to make the transition from Siberia to Alaska and move from continental Europe to England. It is quite possible that during interglacial periods, the two largest ice masses on Earth - Antarctica and Greenland - have undergone slight changes throughout history.

At the peak of glaciation, the average temperature drop varied significantly depending on the area: 100 °C in Alaska, 60 °C in England, 20 °C in the tropics and remained virtually unchanged at the equator. Studies of the last glaciations in North America and Europe, which occurred during the Pleistocene era, gave the same results in this geological area within the last two (approximately) million years.

The last 100,000 years are of particular importance to understanding human evolution. Ice ages became a severe test for the inhabitants of the Earth. After the end of the next glaciation, they again had to adapt and learn to survive. When the climate became warmer, sea levels rose, new forests and plants appeared, and the land rose, freed from the pressure of the ice shell.

Hominids had the most natural resources to adapt to changing conditions. They were able to move to areas with the greatest amount of food resources, where the slow process of their evolution began.
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1.8 million years ago, the Quaternary (anthropogenic) period of the geological history of the earth began and continues to this day.

River basins expanded. There was a rapid development of the mammal fauna, especially mastodons (which would later become extinct, like many other ancient animal species), ungulates and great apes. In that geological period In the history of the earth, man appears (hence the word anthropogenic in the name of this geological period).

The Quaternary period marks a sharp change in climate throughout the European part of Russia. From warm and humid Mediterranean, it turned into moderately cold, and then into cold Arctic. This led to glaciation. Ice accumulated on the Scandinavian Peninsula, in Finland, on the Kola Peninsula and spread to the south.

The Oksky glacier with its southern edge covered the territory of the modern Kashira region, including our region. The first glaciation was the coldest; tree vegetation in the Oka region disappeared almost completely. The glacier did not last long. The first Quaternary glaciation reached the Oka valley, which is why it received the name “Oka glaciation”. The glacier left moraine deposits dominated by boulders of local sedimentary rocks.

But such favorable conditions were again replaced by a glacier. Glaciation was on a planetary scale. The grandiose Dnieper glaciation began. The thickness of the Scandinavian ice sheet reached 4 kilometers. The glacier moved across the Baltic to Western Europe and European part Russia. The boundaries of the tongues of the Dnieper glaciation passed in the area of ​​modern Dnepropetrovsk and almost reached Volgograd.

Mammoth fauna

The climate warmed again and became Mediterranean. In place of the glaciers, heat-loving and moisture-loving vegetation has spread: oak, beech, hornbeam and yew, as well as linden, alder, birch, spruce and pine, and hazel. Ferns grew in the swamps, characteristic of modern South America. The restructuring of the river system and the formation of Quaternary terraces in river valleys began. This period was called the interglacial Oka-Dnieper age.

The Oka served as a kind of barrier to the advancement of ice fields. According to scientists, the right bank of the Oka, i.e. our region has not turned into a continuous icy desert. Here there were fields of ice, interspersed with intervals of thawed hills, between which rivers of meltwater flowed and lakes accumulated.

Ice flows of the Dnieper glaciation brought glacial boulders from Finland and Karelia to our region.

The valleys of old rivers were filled with mid-moraine and fluvioglacial deposits. It became warmer again, and the glacier began to melt. Streams of meltwater rushed south along the beds of new rivers. During this period, third terraces are formed in river valleys. Formed in the depressions big lakes. The climate was moderately cold.

Our region was dominated by forest-steppe vegetation with a predominance of coniferous and birch forests and large areas of steppes covered with wormwood, quinoa, cereals and forbs.

The interstadial era was short. The glacier returned to the Moscow region again, but did not reach the Oka, stopping not far from the southern outskirts of modern Moscow. Therefore, this third glaciation was called the Moscow glaciation. Some tongues of the glacier reached the Oka valley, but they did not reach the territory of the modern Kashira region. The climate was harsh, and the landscape of our region is becoming close to the steppe tundra. Forests are almost disappearing and steppes are taking their place.

A new warming has arrived. The rivers deepened their valleys again. Second river terraces were formed, and the hydrography of the Moscow region changed. It was during that period that the modern valley and basin of the Volga, which flows into the Caspian Sea, was formed. The Oka, and with it our river B. Smedva and its tributaries, entered the Volga river basin.

This interglacial period in climate went through stages from continental temperate (close to modern) to warm, with a Mediterranean climate. In our region, at first birches, pine and spruce dominated, and then heat-loving oaks, beeches and hornbeams began to turn green again. In the swamps grew the Brasia water lily, which today can only be found in Laos, Cambodia or Vietnam. At the end of the interglacial period, birch forests again dominated coniferous forests.

This idyll was spoiled by the Valdai glaciation. Ice from the Scandinavian Peninsula again rushed south. This time the glacier did not reach the Moscow region, but changed our climate to subarctic. For many hundreds of kilometers, including through the territory of the current Kashira district and rural settlement Znamenskoye, there is a stretch of steppe-tundra, with dried grass and sparse bushes, dwarf birches and polar willows. These conditions were ideal for the mammoth fauna and for primitive man, who then already lived on the boundaries of the glacier.

During the last Valdai glaciation, the first river terraces were formed. The hydrography of our region has finally taken shape.

Traces of ice ages are often found in the Kashira region, but they are difficult to identify. Of course, large stone boulders are traces of glacial activity of the Dnieper glaciation. They were brought by ice from Scandinavia, Finland and the Kola Peninsula. The oldest traces of a glacier are moraine or boulder loam, which is a disordered mixture of clay, sand, and brown stones.

The third group of glacial rocks are sands resulting from the destruction of moraine layers by water. These are sands with large pebbles and stones and homogeneous sands. They can be observed on the Oka. These include Belopesotsky Sands. Often found in the valleys of rivers, streams, and ravines, layers of flint and limestone rubble are traces of the beds of ancient rivers and streams.

With the new warming, the geological epoch of the Holocene began (it began 11 thousand 400 years ago), which continues to this day. The modern river floodplains were finally formed. The mammoth fauna became extinct, and forests appeared in place of the tundra (first spruce, then birch, and later mixed). The flora and fauna of our region has acquired modern features - the one we see today. At the same time, the left and right banks of the Oka still differ greatly in their forest cover. If the right bank is dominated mixed forests and many open areas, the left bank is dominated by continuous coniferous forests - these are traces of glacial and interglacial climate changes. On our bank of the Oka the glacier left less footprints and our climate was somewhat milder than on the left bank of the Oka.

Geological processes continue today. Earth's crust in the Moscow region over the past 5 thousand years it has risen only slightly, at a rate of 10 cm per century. The modern alluvium of the Oka and other rivers of our region is being formed. What this will lead to after millions of years, we can only guess, because, having briefly become acquainted with geological history our region, we can safely repeat the Russian proverb: “Man proposes, but God disposes.” This saying is especially relevant after we have become convinced in this chapter that human history is a grain of sand in the history of our planet.

GLACIAL PERIOD

In distant, distant times, where Leningrad, Moscow, and Kyiv are now, everything was different. Dense forests grew along the banks of ancient rivers, and shaggy mammoths with curved tusks, huge hairy rhinoceroses, tigers and bears much larger than today roamed there.

Gradually it became colder and colder in these places. Far in the north, so much snow fell every year that entire mountains accumulated it - larger than the present-day Ural Mountains. The snow compacted, turned into ice, then began to slowly, slowly creep away, spreading in all directions.

The ancient forests are approaching ice mountains. The winds from these mountains are cold, evil winds, the trees froze and animals fled south from the cold. And the icy mountains crawled further to the south, turning out rocks along the way and moving entire hills of earth and stones in front of them. They crawled to the place where Moscow now stands, and crawled even further, into the warm southern countries. They reached the hot Volga steppe and stopped.

Here, finally, the sun overpowered them: the glaciers began to melt. Huge rivers flowed from them. And the ice retreated, melted, and the masses of stones, sand and clay that the glaciers brought remained lying in the southern steppes.

More than once, terrible ice mountains have approached from the north. Have you seen the cobblestone street? Such small stones were brought by the glacier. And there are boulders as big as a house. They still lie in the north.

But the ice may move again. Just not soon. Maybe thousands of years will pass. And not only the sun will then fight the ice. If necessary, people will use ATOMIC ENERGY and prevent the glacier from entering our land.

When did the Ice Age end?

Many of us believe that the Ice Age ended a long time ago and no traces of it remain. But geologists say we are only approaching the end of the Ice Age. And the people of Greenland are still living in the Ice Age.

About 25 thousand years ago, the peoples who inhabited the central part of NORTH AMERICA saw ice and snow all year round. A huge wall of ice stretched from the Pacific to the Atlantic Ocean, and north to the Pole itself. This was during the final stages of the Ice Age, when all of Canada, most of the United States and northwestern Europe were covered in a layer of ice more than one kilometer thick.

But this does not mean that it was always very cold. In the northern part of the United States, temperatures were only 5 degrees lower than today. Cold summer months caused an ice age. At this time, the heat was not enough to melt the ice and snow. It accumulated and eventually covered the entire northern part of these areas.

The Ice Age consisted of four stages. At the beginning of each of them, ice formed moving south, then melted and retreated to the NORTH POLE. This happened, it is believed, four times. Cold periods are called “glaciations”, warm periods are called “interglacial” periods.

The first stage in North America is thought to have begun about two million years ago, the second about 1,250,000 years ago, the third about 500,000 years ago, and the last about 100,000 years ago.

Ice melting rate last stage ice age in different areas was different. For example, in the area where the modern state of Wisconsin is located in the USA, the melting of ice began approximately 40,000 years ago. The ice that covered the New England region of the United States disappeared about 28,000 years ago. And the territory of the modern state of Minnesota was freed by ice only 15,000 years ago!

In Europe, Germany became ice-free 17,000 years ago, and Sweden only 13,000 years ago.

Why do glaciers still exist today?

The huge mass of ice that began the Ice Age in North America was called the “continental glacier”: in the very center its thickness reached 4.5 km. This glacier may have formed and melted four times during the entire Ice Age.

The glacier that covered other parts of the world did not melt in some places! For example, the huge island of Greenland is still covered by a continental glacier, except for a narrow coastal strip. In its middle part, the glacier sometimes reaches a thickness of more than three kilometers. Antarctica is also covered by an extensive continental glacier, with ice up to 4 kilometers thick in some places!

Therefore, the reason why there are glaciers in some areas of the globe is because they have not melted since the Ice Age. But the bulk of the glaciers found today were formed recently. They are mainly located in mountain valleys.

They originate in wide, gentle, amphitheatrically shaped valleys. Snow gets here from the slopes as a result of landslides and avalanches. Such snow does not melt in the summer, becoming deeper every year.

Gradually, pressure from above, some thawing, and refreezing remove air from the bottom of this snow mass, turning it into solid ice. The impact of the weight of the entire mass of ice and snow compresses the entire mass and causes it to move down the valley. This moving tongue of ice is a mountain glacier.

In Europe, more than 1,200 such glaciers are known in the Alps! They also exist in the Pyrenees, the Carpathians, the Caucasus, and in the mountains of southern Asia. There are tens of thousands of similar glaciers in southern Alaska, some 50 to 100 km long!

Consequences of warming

The last ice age led to the appearance of the woolly mammoth and a huge increase in the area of ​​glaciers. But it was only one of many that cooled the Earth throughout its 4.5 billion years of history.

So, how often does the planet experience ice ages and when should we expect the next one?

Major periods of glaciation in the history of the planet

The answer to the first question depends on whether you are talking about large glaciations or small ones that occur during these long periods. Throughout history, the Earth has experienced five major periods of glaciation, some of which lasted for hundreds of millions of years. In fact, even now the Earth is experiencing a large period of glaciation, and this explains why it has polar ice caps.

The five main ice ages are the Huronian (2.4-2.1 billion years ago), the Cryogenian glaciation (720-635 million years ago), the Andean-Saharan glaciation (450-420 million years ago), and the Late Paleozoic glaciation (335-260 million years ago). million years ago) and Quaternary (2.7 million years ago to the present).

These major periods of glaciation may alternate between smaller ice ages and warm periods (interglacials). At the beginning of the Quaternary Glaciation (2.7-1 million years ago), these cold ice ages occurred every 41 thousand years. However, in the last 800 thousand years, significant ice ages have occurred less frequently - approximately every 100 thousand years.

How does the 100,000 year cycle work?

The ice sheets grow for about 90 thousand years and then begin to melt during the 10 thousand year warm period. Then the process is repeated.

Given that the last ice age ended about 11,700 years ago, perhaps it's time for another one to begin?

Scientists believe we should be experiencing another ice age right now. However, there are two factors associated with the Earth's orbit that influence the formation of warm and cold periods. Considering also how much carbon dioxide we emit into the atmosphere, the next ice age won't start for at least 100,000 years.

What causes an ice age?

The hypothesis put forward by Serbian astronomer Milutin Milanković explains why cycles of glacial and interglacial periods exist on Earth.

As a planet orbits the Sun, the amount of light it receives from it is affected by three factors: its inclination (which ranges from 24.5 to 22.1 degrees on a 41,000-year cycle), its eccentricity (the change in the shape of its orbit around of the Sun, which fluctuates from a near circle to an oval shape) and its wobble (one full wobble occurs every 19-23 thousand years).

In 1976, a landmark paper in the journal Science presented evidence that these three orbital parameters explained the planet's glacial cycles.

Milankovitch's theory is that orbital cycles are predictable and very consistent in the history of the planet. If the Earth is experiencing an ice age, it will be covered with more or less ice, depending on these orbital cycles. But if the Earth is too warm, no change will occur, at least in terms of increasing amounts of ice.

What can affect the warming of the planet?

The first gas that comes to mind is carbon dioxide. Over the past 800 thousand years, carbon dioxide levels have ranged from 170 to 280 parts per million (meaning that out of 1 million air molecules, 280 are carbon dioxide molecules). A seemingly insignificant difference of 100 parts per million results in glacial and interglacial periods. But carbon dioxide levels are significantly higher today than in past periods of fluctuation. In May 2016, carbon dioxide levels over Antarctica reached 400 parts per million.

The Earth has warmed up this much before. For example, during the time of dinosaurs the air temperature was even higher than it is now. But the problem is that in the modern world it is growing at a record pace because we have released too much carbon dioxide into the atmosphere in a short time. Moreover, given that the rate of emissions is not currently decreasing, we can conclude that the situation is unlikely to change in the near future.

Consequences of warming

The warming caused by this carbon dioxide will have big consequences because even a small increase in the Earth's average temperature can lead to dramatic changes. For example, the Earth was on average only 5 degrees Celsius colder during the last ice age than it is today, but this led to a significant change in regional temperatures, the disappearance of huge parts of flora and fauna, and the emergence of new species.

If global warming causes all the ice sheets of Greenland and Antarctica to melt, sea levels will rise by 60 meters compared to today's levels.

What causes major ice ages?

The factors that caused long periods of glaciation, such as the Quaternary, are not as well understood by scientists. But one idea is that a massive drop in carbon dioxide levels could lead to colder temperatures.

For example, according to the uplift and weathering hypothesis, when plate tectonics causes mountain ranges to grow, new exposed rock appears on the surface. It easily weathers and disintegrates when it ends up in the oceans. Marine organisms use these rocks to create their shells. Over time, stones and shells take carbon dioxide from the atmosphere and its level drops significantly, which leads to a period of glaciation.

During the Paleogene, the northern hemisphere had a warm and humid climate, but during the Neogene (25 - 3 million years ago) it became much colder and drier. Environmental changes associated with cooling and the appearance of glaciations are a feature Quaternary period. For this reason it is sometimes called the Ice Age.

Ice ages have occurred several times in Earth's history. Traces of continental glaciations were found in the layers of the Carboniferous and Permian (300 - 250 million years), Vendian (680 - 650 million years), Riphean (850 - 800 million years). The oldest glacial deposits discovered on Earth are more than 2 billion years old.

No single planetary or cosmic factor causing glaciation has been found. Glaciations are the result of a combination of several events, some of which play the main role, while others play the role of a “trigger” mechanism. It has been noted that all the great glaciations of our planet coincided with the largest mountain-building epochs, when the relief of the earth's surface was most contrasting. The area of ​​the seas has decreased. Under these conditions, climate fluctuations have become more severe. Mountains up to 2000 m high that arose in Antarctica, i.e. directly at the South Pole of the Earth, became the first source of formation of ice sheets. Glaciation of Antarctica began more than 30 million years ago. The appearance of a glacier there greatly increased the reflectivity, which in turn led to a decrease in temperature. Gradually, the glacier of Antarctica grew both in area and in thickness, and its influence on the thermal regime of the Earth increased. The temperature of the ice slowly dropped. The Antarctic continent has become the largest cold accumulator on the planet. The formation of huge plateaus in Tibet and the western part of the North American continent made a major contribution to climate change in the Northern Hemisphere.

It became colder and colder, and about 3 million years ago, the Earth’s climate as a whole became so cold that periodically they began to ice ages, during which ice sheets covered most of the northern hemisphere. Mountain-forming processes are a necessary but not sufficient condition for the occurrence of glaciation. The average heights of mountains are now no lower, and perhaps even higher, than they were during the glaciation. However, now the area of ​​glaciers is relatively small. Some additional reason is needed that directly causes the cold snap.

It should be emphasized that any significant decrease in temperature is not required for major glaciation of the planet to occur. Calculations show that the overall average annual decrease in temperature on Earth by 2 - 4? C will cause the spontaneous development of glaciers, which in turn will lower the temperature on Earth. As a result, the glacial shell will cover a significant part of the Earth's area.

Carbon dioxide plays a huge role in regulating the temperature of surface layers of air. Carbon dioxide freely transmits the sun's rays to the earth's surface, but absorbs most of the planet's thermal radiation. It is a colossal screen that prevents the cooling of our planet. Currently, the carbon dioxide content in the atmosphere does not exceed 0.03%. If this figure is halved, then average annual temperatures in mid-latitudes will decrease by 4–5? C, which could lead to the beginning of an ice age. According to some data, the concentration of CO2 in the atmosphere was about a third less during glacial periods than during interglacial periods. sea ​​water contained 60 times more carbon dioxide than the atmosphere.

The decrease in CO2 content in the atmosphere can be explained by the following mechanisms. If the rate of spreading (moving apart) and, accordingly, subduction decreased significantly during some periods, then this should have led to the entry of less carbon dioxide into the atmosphere. In fact, global average spreading rates show little change over the past 40 million years. If the rate of replacement of CO2 was practically unchanged, then the rate of its removal from the atmosphere due to chemical weathering of rocks increased significantly with the appearance of giant plateaus. In Tibet and America, carbon dioxide combines with rainwater and groundwater to form carbon dioxide, which reacts with silicate minerals in rocks. The resulting bicarbonate ions are transported to the oceans, where they are consumed by organisms such as plankton and corals and then deposited on the ocean floor. Of course, these sediments will fall into the subduction zone, melt, and CO2 will again enter the atmosphere as a result of volcanic activity, but this process takes a long time, from tens to hundreds of millions of years.

It may seem that as a result of volcanic activity the CO2 content in the atmosphere will increase and therefore be warmer, but this is not entirely true.

The study of modern and ancient volcanic activity allowed volcanologist I.V. Melekestsev to connect the cooling and the glaciation that caused it with an increase in the intensity of volcanism. It is well known that volcanism significantly affects the earth's atmosphere, changing its gas composition, temperature, and also polluting it with finely divided volcanic ash material. Huge masses of ash, measured in billions of tons, are ejected by volcanoes into the upper atmosphere and then carried by jet streams throughout the globe. A few days after the Bezymyanny volcano erupted in 1956, its ashes were discovered in upper layers troposphere over London, Ash material ejected during the 1963 eruption of Mount Agung on the island of Bali (Indonesia) was found at an altitude of about 20 km above North America and Australia. Pollution of the atmosphere by volcanic ash causes a significant decrease in its transparency and, consequently, a weakening of solar radiation by 10-20% against the norm. In addition, ash particles serve as condensation nuclei, contributing to great development cloudiness. An increase in cloudiness, in turn, noticeably reduces the amount of solar radiation. According to Brooks’ calculations, an increase in cloudiness from 50 (typical for the present) to 60% would lead to a decrease average annual temperature on globe at 2° C.

1. How many ice ages were there?
2. How does the Ice Age relate to biblical history?
3. How much of the earth was covered with ice?
4. How long did the Ice Age last?
5. What do we know about frozen mammoths?
6. How did the Ice Age affect humanity?

We have clear evidence that there was an ice age in the history of the Earth. To this day we see its traces: glaciers and U-shaped valleys along which the glacier retreated. Evolutionists claim that there were several such periods, each lasting twenty to thirty million years (or so).

They were interspersed with relatively warm interglacial intervals, accounting for about 10% of the total time. The last ice age began two million years ago and ended eleven thousand years ago. Creationists, for their part, generally believe that the Ice Age began shortly after the Flood and lasted less than a thousand years. Next we will see that biblical story The Flood offers a compelling explanation for this the only one ice age. For evolutionists, the explanation of any ice age is associated with great difficulties.

The oldest ice ages?

Based on the principle that the present is the key to understanding the past, evolutionists argue that there is evidence of early ice ages. However, the difference between the rocks of different geological systems and the landscape features of the present period is very large, and their similarity is insignificant3-5. Modern glaciers grind rock as they move and create sediments consisting of fragments of different sizes.

These conglomerates, called style or tillite, form a new breed. The abrasive action of rocks enclosed in the thickness of the glacier forms parallel grooves in the rocky base along which the glacier moves - the so-called striation. When the glacier melts slightly in summer, rock “dust” is released, which is washed into glacial lakes, and alternating coarse-grained and fine-grained layers are formed at their bottom (the phenomenon seasonal layering).

Sometimes a piece of ice with boulders frozen into it breaks off from a glacier or ice sheet, falls into such a lake and melts. This is why huge boulders are sometimes found in layers of fine-grained sediment at the bottom of glacial lakes. Many geologists argue that all these patterns are also observed in ancient rocks, and, therefore, not when there were other, earlier ice ages on earth. However, there is a number of evidence that the observational facts are misinterpreted.

Consequences present Ice Ages still exist today: first of all, these are the giant ice sheets covering Antarctica and Greenland, Alpine glaciers, and numerous changes in the shape of the landscape of glacial origin. Since we observe all these phenomena on modern Earth, it is obvious that the Ice Age began after the Flood. During the Ice Age, huge ice sheets covered Greenland, much of North America(all the way to the northern United States) and Northern Europe– from Scandinavia to England and Germany (see figure on pages 10–11).

On the tops of North American Rocky Mountains, European Alps and others mountain ranges non-melting ice caps have been preserved, and vast glaciers descend along the valleys almost to their very foot. In the Southern Hemisphere, ice sheets cover most of Antarctica. Ice caps lie on the mountains of New Zealand, Tasmania and the highest peaks in southeastern Australia. There are still glaciers in the Southern Alps of New Zealand and the South American Andes, and in Snowy mountains But in South Wales and Tasmania, landscape forms formed as a result of glacier activity remain.

Almost all textbooks say that during the Ice Age the ice advanced and retreated at least four times, and between glaciations there were periods of warming (the so-called “interglacials”). Trying to discover the cyclical pattern of these processes, geologists suggested that more than twenty glaciations and interglacials occurred over two million years. However, the emergence of dense clay soils, old river terraces and other phenomena that are considered evidence of numerous glaciations are more legitimately considered as consequences of different phases the only one ice age that occurred after the Flood.

Ice Age and man

Never, even during periods of the most severe glaciations, did ice cover more than a third of the earth's surface. At the same time that glaciation was occurring in the polar and temperate latitudes, heavy rains probably occurred closer to the equator. They abundantly irrigated even those regions where today there are waterless deserts - the Sahara, Gobi, Arabia. During archaeological excavations numerous evidence of the existence of abundant vegetation, active human activity And complex systems irrigation in now barren lands.

There is also evidence that throughout the entire ice age, at the edge of the ice sheet in Western Europe people lived - in particular, Neanderthals. Many anthropologists now recognize that some of the “beast-likeness” of the Neanderthals was largely due to diseases (rickets, arthritis) that plagued these people in the cloudy, cold and damp European climate of that time. Rickets was common due to poor nutrition and due to lack of sunlight to stimulate the synthesis of vitamin D, which is necessary for normal bone development.

With the exception of very unreliable dating methods (see. « What does radiocarbon dating show?» ), there is no reason to deny that Neanderthals could have been contemporaries of the civilizations of Ancient Egypt and Babylon, which flourished in southern latitudes. The idea that the ice age lasted seven hundred years is much more plausible than the hypothesis of two million years of glaciation.

The Great Flood is the reason for the Ice Age

In order for masses of ice to begin to accumulate on land, the oceans in temperate and polar latitudes must be much warmer than the earth's surface - especially in summer. Large amounts of water evaporate from the surface of warm oceans, which then moves towards land. On cold continents, most precipitation falls as snow rather than rain; In summer this snow melts. This allows ice to accumulate quickly. Evolutionary models that explain the Ice Age as "slow and gradual" processes are untenable. Long epoch theories speak of gradual cooling on Earth.

But such a cooling would not lead to an ice age at all. If the oceans gradually cooled at the same time as the land, then after a while it would become so cold that snow would no longer melt in the summer, and evaporation of water from the ocean surface would not provide enough snow to form massive ice sheets. The result of all this would not be an ice age, but the formation of a snowy (polar) desert.

And here Global flood, described in the Bible, provided a very simple mechanism for the Ice Age. Towards the end of this global catastrophe, when hot water poured into the antediluvian oceans The groundwater, and also as a result of volcanic activity, a large amount of thermal energy was released into the water, the oceans were most likely warm. Ord and Vardiman show that just before the Ice Age, ocean waters were indeed warmer: this is evidenced by oxygen isotopes in the shells of tiny marine animals - foraminifera.

Volcanic dust and aerosols, which ended up in the air due to residual volcanic phenomena at the end of the Flood and after it, reflected solar radiation back into space, causing a general, especially summer, cooling on Earth.

Dust and aerosols gradually disappeared from the atmosphere, but volcanic activity that continued after the Flood replenished their reserves for hundreds of years. Evidence of continued and widespread volcanism is the large amount of volcanic rocks among the so-called Pleistocene sediments, which probably formed shortly after the Flood. Vardiman, using generally known information about the movement air masses, showed that warm post-Flood oceans, combined with cooling at the poles, caused strong convection currents in the atmosphere, which created a huge hurricane zone over most of the Arctic. It persisted for more than five hundred years, until the glacial maximum (see the next section).

Such a climate led to precipitation in polar latitudes large quantity snow masses that quickly glaciated and formed ice sheets. These shields first covered the land, and then, towards the end of the Ice Age, as the water cooled, they began to spread to the oceans.

How long did the Ice Age last?

Meteorologist Michael Ord calculated that it would take seven hundred years for the polar oceans to cool from a constant temperature of 30°C at the end of the Flood to today's temperature (averaging 40°C). It is this period that should be considered the duration of the ice age. Ice began to accumulate shortly after the Flood. About five hundred years later average temperature The temperature of the world's oceans dropped to 10 0 C, evaporation from its surface decreased significantly, and cloud cover thinned. The amount of volcanic dust in the atmosphere had also decreased by this time. As a result, the Earth's surface began to be warmed up more intensely by the sun's rays, and the ice sheets began to melt. Thus, the glacial maximum occurred five hundred years after the Flood.

It is interesting to note that references to this occur in the book of Job (37:9-10; 38:22-23, 29-30), which tells of events that most likely occurred at the end of the Ice Age. (Job lived in the land of Uz, and Uz was a descendant of Shem—Genesis 10:23—so most conservative Bible students believe that Job lived after the Babel but before Abraham.) God asked Job from the storm: “From whose belly comes the ice and the frost of heaven, who gives birth to it? The waters grow strong like a rock, and the surface of the deep freezes” (Job 38:29-30). These questions assume that Job knew, either directly or from historical/family traditions, what God was talking about.

These words probably refer to the climatic consequences of the Ice Age, now unnoticeable in the Middle East. IN last years The theoretical duration of the ice age was greatly supported by the assertion that boreholes drilled into the Antarctic and Greenland ice sheets contained many thousands of annual layers. These layers are clearly visible at the top of the boreholes and cores recovered from them, consistent with the last few thousand years—as would be expected if the layers represent annual snow deposition since the end of the Ice Age. Below, the so-called annual layers become less distinct, that is, most likely, they did not arise seasonally, but under the influence of other mechanisms - for example, individual hurricanes.

The burial and freezing of mammoth carcasses cannot be explained using uniformitarian/evolutionary hypotheses of a “slow and gradual” cooling over millennia and an equally gradual warming. But if for evolutionists frozen mammoths are great mystery, then within the framework of the Flood/Ice Age theory this is easily explained. Michel Ord believes that the burial and freezing of mammoths occurred at the end of the post-Flood Ice Age.

Let us take into account that until the end of the Ice Age, the Arctic Ocean was warm enough that there were no ice sheets either on the surface of the water or in the coastal valleys; it provided enough temperate climate in the coastal zone. It is important to note that the remains of mammoths are found in the largest quantities in areas close to the coasts of the Northern Arctic Ocean, while these animals lived much further south of the maximum distribution of ice sheets. Consequently, it was the distribution of ice sheets that determined the area of ​​mass death of mammoths.

Hundreds of years after the Flood, the waters of the oceans cooled noticeably, the humidity of the air above them decreased, and the coast of the Arctic Ocean turned into an area of ​​arid climate, which resulted in droughts. From under the melting ice sheets, land appeared, from which masses of sand and mud rose like a whirlwind, burying many mammoths alive. This explains the presence of carcasses in decomposed peat containing loess– silty sediments. Some mammoths were buried standing up. The subsequent cold snap froze the oceans and land again, causing the mammoths previously buried under sand and mud to freeze and remain in this form to this day.

The animals that descended from the Ark multiplied on Earth over several centuries. But some of them died out without surviving the Ice Age and global climate change. Some, including mammoths, died in the disasters that accompanied these changes. Following the end of the Ice Age, global precipitation patterns changed again, turning many areas into deserts - causing animal extinctions to continue. The Flood and the subsequent Ice Age, volcanic activity and desertification radically changed the appearance of the Earth and caused the depletion of its flora and fauna to current state. The surviving evidence best agrees with the biblical account of history.

Here's the Good News

Creation Ministries International is committed to glorifying and honoring the Creator God and affirming the truth of what the Bible describes true story origin of the world and man. Part of this story is the bad news of Adam's violation of God's command. This brought death, suffering and separation from God into the world. These results are known to everyone. All of Adam's descendants are afflicted with sin from the moment of conception (Psalm 51:7) and share in Adam's disobedience (sin). They can no longer be in the presence of the Holy God and are doomed to separation from Him. The Bible says that “all have sinned and fall short of the glory of God” (Romans 3:23), and that all “shall suffer the punishment of everlasting destruction from the presence of the Lord and from the glory of his power” (2 Thessalonians 1:9). But there is also good news: God did not remain indifferent to our misfortune. “For God so loved the world that he gave his only begotten Son, that whoever believes in him should not perish but have eternal life.”(John 3:16).

Jesus Christ, the Creator, being sinless, took upon Himself the guilt for the sins of all mankind and their consequences - death and separation from God. He died on the cross, but on the third day he rose again, having conquered death. And now everyone who sincerely believes in Him, repents of their sins and relies not on themselves, but on Christ, can return to God and remain in eternal communion with their Creator. “He who believes in Him is not condemned, but he who does not believe is already condemned, because he has not believed in the name of the only begotten Son of God.”(John 3:18). Marvelous is our Savior and wonderful is salvation in Christ, our Creator!