The last great glaciation of the territory of the USSR. On the issue of the boundary of the maximum Quaternary glaciation within the Ural ridge in connection with observations over upland terraces
Currently, the global volume of ice is over 20 million cubic kilometers. According to some scientists, it takes more than 5,000 years for all of it to melt. If humanity continues to burn fossil fuels, it is very likely that we will end up with an ice-free planet with an average temperature of 26°C instead of the current 14°C.
The presented maps show our world as it looks now, with one difference: all the ice on Earth turned into water, which led to a rise in sea levels of 65 meters and the formation of new coastlines along the continents and inland seas.
So, let's see what a "melted" world can be like.
The entire Atlantic coast along Florida and the Gulf of Mexico will disappear. The hills of San Francisco in California will become a cluster of islands, and the Central Valley will become a giant bay. The Gulf of California will extend north above the latitude of San Diego.
South America
The Amazon Basin to the north and the Paraguay River Basin to the south would become Atlantic inlets, wiping out Buenos Aires, Uruguay's coastal regions, and much of Paraguay. Mountainous areas would have survived along the Caribbean coast and in Central America.
Africa
Compared to other continents, Africa will lose the least amount of land due to rising sea levels, but rising global temperatures could make many of its territories uninhabitable. In Egypt, Alexandria and Cairo will be flooded by the Mediterranean Sea.
Europe
London will remain only a memory, as will Venice, swallowed up by the Adriatic Sea. Thousands of years later, according to this catastrophic scenario, the Netherlands and most of Denmark will also go under water. At the same time, the Black and Caspian Seas, fed by Mediterranean waters, will expand more and more.
Asia
Lands now inhabited by 600 million Chinese will be flooded, as will Bangladesh, with a population of 160 million, and much of coastal India. In Cambodia, in the Mekong Delta, only the Cardamom Mountains will remain in the form of an island on the shallows.
Australia
The largely desert continent would gain a new inland sea - but would lose much of the narrow coastal strip that currently houses four-fifths of the population.
Antarctic
The East Antarctic ice sheet is so large (accounting for four-fifths of all ice on Earth) that it may seem stable. He survived the previous warm periods, remaining unscathed. But in Lately due to global warming, its thickening is very small. Although the warmer the atmosphere, the more water vapor it contains, which falls on the region in the form of snow. But even this "ice monster" is unlikely to withstand the return of the climate of the Eocene era.
Like the Greenland ice sheet, West Antarctica was apparently much smaller in more early periods warming. These regions are vulnerable, as most of their territory is rock, located below sea level. When the ocean warms, the ice sheet melts from below, which contributes to its destruction. Since 1992, it has lost an average of 65 million tons of ice per year.
Prior to this, scientists for decades predicted the imminent onset of global warming on Earth, due to industrial human activity, and assured that "there would be no winter." Today, the situation seems to have changed dramatically. Some scientists believe that a new ice age is beginning on Earth.
This sensational theory belongs to an oceanologist from Japan - Mototake Nakamura. According to him, starting from 2015, the Earth will begin to cool. His point of view is also supported by a Russian scientist, Khababullo Abdusammatov from the Pulkovo Observatory. Recall that the last decade was the warmest for the entire period of meteorological observations, i.e. since 1850.
Scientists believe that already in 2015 there will be a decrease in solar activity, which will lead to climate change and its cooling. The temperature of the ocean will decrease, the amount of ice will increase, and the overall temperature will drop significantly.
Cooling will reach its maximum in 2055. From this moment, a new ice age will begin, which will last 2 centuries. Scientists have not specified how severe the icing will be.
There is a positive point in all this, it seems that polar bears are no longer threatened with extinction)
Let's try to figure it all out.
1 Ice Ages can last hundreds of millions of years. The climate at this time is colder, continental glaciers are formed.
For example:
Paleozoic Ice Age - 460-230 Ma
Cenozoic Ice Age - 65 million years ago - present.
It turns out that in the period between: 230 million years ago and 65 million years ago, it was much warmer than now, and we live in the Cenozoic Ice Age today. Well, we figured out the eras.
2 The temperature during the ice age is not uniform, but also changes. Ice ages can be distinguished within an ice age.
glacial period(from Wikipedia) - a periodically repeating stage in the geological history of the Earth lasting several million years, during which, against the background of a general relative cooling of the climate, repeated sharp growths of continental ice sheets - ice ages occur. These epochs, in turn, alternate with relative warmings - epochs of glaciation reduction (interglacials).
Those. we get a nesting doll, and inside the cold ice age, there are even colder segments, when the glacier covers the continents from above - ice ages.
We live in the Quaternary Ice Age. But thank God during the interglacial.
The last ice age (Vistula glaciation) began ca. 110 thousand years ago and ended around 9700-9600 BC. e. And this is not so long ago! 26-20 thousand years ago, the volume of ice was at its maximum. Therefore, in principle, there will definitely be another glaciation, the only question is when exactly.
Map of the Earth 18 thousand years ago. As you can see, the glacier covered Scandinavia, Great Britain and Canada. Note also the fact that the level of the ocean has dropped and many parts have risen from the water. earth's surface now under water.
The same card, only for Russia.
Perhaps the scientists are right, and we will be able to observe with our own eyes how new lands protrude from under the water, and the glacier takes the northern territories for itself.
Come to think of it, the weather has been pretty stormy lately. Snow fell in Egypt, Libya, Syria and Israel for the first time in 120 years. There was even snow in tropical Vietnam. In the USA for the first time in 100 years, and the temperature dropped to a record -50 degrees Celsius. And all this against the backdrop of positive temperatures in Moscow.
The main thing is to prepare well for the ice age. Buy a site in the southern latitudes, away from big cities (there are always full of hungry people during natural disasters). Make an underground bunker there with food supplies for years, buy weapons for self-defense and prepare for life in the style of Survival horror))
The climate of the Earth periodically undergoes serious changes associated with alternating large-scale cooling, accompanied by the formation of stable ice sheets on the continents, and warming. The last glacial epoch, which ended approximately 11-10 thousand years ago, for the territory of the East European Plain is called the Valdai glaciation.
Systematics and terminology of periodic cold snaps
The longest stages of general cooling in the history of our planet's climate are called cryo-eras, or ice ages lasting up to hundreds of millions of years. At present, the Cenozoic cryo-era has been going on for about 65 million years on Earth and, apparently, will continue for a very long time (judging by previous similar stages).
Throughout the eras, scientists identify ice ages, interspersed with phases of relative warming. Periods can last millions and tens of millions of years. The modern ice age is the Quaternary (the name is given in accordance with the geological period) or, as is sometimes said, the Pleistocene (according to a smaller geochronological unit - the epoch). It began about 3 million years ago and, apparently, is still far from over.
In turn, ice ages are made up of shorter-term - several tens of thousands of years - ice epochs, or glaciations (sometimes the term "glacial" is used). The warm intervals between them are called interglacials, or interglacials. We now live precisely during such an interglacial epoch, which replaced the Valdai glaciation on the Russian Plain. Glaciations in the presence of undoubted common features are characterized by regional characteristics, therefore they are named after a particular locality.
Within the epochs, stages (stadials) and interstadials are distinguished, during which the climate experiences the shortest fluctuations - pessima (cooling) and optima. The present time is characterized by the climatic optimum of the subatlantic interstadial.
Age of the Valdai glaciation and its phases
According to the chronological framework and conditions of division into stages, this glacier differs somewhat from the Würm (Alps), Vistula ( Central Europe), Wisconsin (North America) and other corresponding ice sheets. On the East European Plain, the beginning of the era that replaced the Mikulin interglacial is attributed to about 80 thousand years ago. It should be noted that the establishment of clear time boundaries is a serious difficulty - as a rule, they are blurred - therefore chronological framework stages vary greatly.
Most researchers distinguish two stages of the Valdai glaciation: these are the Kalinin stage with the maximum ice about 70 thousand years ago and the Ostashkov stage (about 20 thousand years ago). They are separated by the Bryansk interstadial - a warming that lasted approximately from 45-35 to 32-24 thousand years ago. Some scientists, however, offer a more fractional division of the era - up to seven stages. As for the retreat of the glacier, it occurred over a period of 12.5 to 10 thousand years ago.
Glacier geography and climatic conditions
The center of the last glaciation in Europe was Fennoscandia (includes the territories of Scandinavia, the Gulf of Bothnia, Finland and Karelia with the Kola Peninsula). From here, the glacier periodically grew to the south, including to the Russian Plain. It was less extensive in scope than the preceding Moscow glaciation. The boundary of the Valdai ice sheet ran in a northeasterly direction and at its maximum did not reach Smolensk, Moscow, and Kostroma. Then, on the territory of the Arkhangelsk region, the border turned sharply to the north to the White and Barents Seas.
In the center of glaciation, the thickness of the Scandinavian ice sheet reached 3 km, which is comparable to the East European Plain glacier, which had a thickness of 1-2 km. Interestingly, with a much less developed ice cover, the Valdai glaciation was characterized by severe climatic conditions. The average annual temperatures during the last glacial maximum - the Ostashkovsky - only slightly exceeded the temperatures of the era of the very powerful Moscow glaciation (-6 °C) and were 6-7 °C lower than modern ones.
Consequences of glaciation
The ubiquitous traces of the Valdai glaciation on the Russian Plain testify to the strong influence it had on the landscape. The glacier erased many of the irregularities left by the Moscow glaciation, and during its retreat, when a huge amount of sand, debris and other inclusions melted out of the ice mass, deposits up to 100 meters thick.
The ice cover moved not in a continuous mass, but in differentiated flows, on the sides of which heaps of detrital material formed - marginal moraines. These are, in particular, some ridges in the current Valdai Upland. In general, the entire plain is characterized by a hilly-morainic surface, for example, a large number of drumlins - low elongated hills.
Very clear traces of glaciation are lakes formed in hollows plowed by a glacier (Ladoga, Onega, Ilmen, Chudskoye and others). The river network of the region also acquired modern look as a result of the ice sheet.
The Valdai glaciation changed not only the landscape, but also the composition of the flora and fauna of the Russian Plain, influenced the area of settlement ancient man- in a word, it had important and multifaceted consequences for the region.
The consequences of warming
The last ice age brought about the appearance of the woolly mammoth and a huge increase in the area of glaciers. But it was only one of many that have cooled the Earth throughout its 4.5 billion years of history.
So, how often does the planet go through ice ages, and when should we expect the next one?
The main periods of glaciation in the history of the planet
The answer to the first question depends on whether you mean the big glaciations or the small ones that occur during these long periods. Throughout history, the Earth has experienced five major glaciations, some of them lasting hundreds of millions of years. In fact, even now, the Earth is going through a large period of glaciation, and this explains why it has polar ice.
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 (450-420 million years ago), the late Paleozoic glaciation (335-260 million years ago) and the 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 41,000 years. However, in the last 800,000 years, significant ice ages have appeared less frequently - about every 100,000 years.
How does the 100,000 year cycle work?
Ice sheets grow for approximately 90,000 years and then begin to melt during the 10,000 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 that 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 how much carbon dioxide we emit into the atmosphere, the next ice age won't start for at least another 100,000 years.
What causes an ice age?
The hypothesis put forward by the Serbian astronomer Milyutin Milanković explains why there are cycles of ice and interglacial periods on Earth.
As the planet revolves around 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 in a 41,000-year cycle), its eccentricity (changing the shape of its orbit around the sun, which oscillates from the near circle to 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 a planet's history. If the Earth is going through an ice age, then it will be covered in more or less ice, depending on these orbital cycles. But if the Earth is too warm, no change will occur, at least in regards to the growing amount of ice.
What can affect the warming of the planet?
The first gas that comes to mind is carbon dioxide. Over the past 800,000 years, carbon dioxide levels have fluctuated between 170 and 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 leads to the appearance of glacial and interglacial periods. But carbon dioxide levels are much higher today than they were in past fluctuations. In May 2016, carbon dioxide levels over Antarctica reached 400 parts per million.
The earth has warmed up so much before. For example, during the time of the dinosaurs, the air temperature was even higher than now. But the problem is that in modern world it is growing at a record pace because we have emitted too much carbon dioxide into the atmosphere for a short time. In addition, given that emission rates are not declining to date, it can be concluded that the situation is unlikely to change in the near future.
The consequences of warming
The warming caused by the presence of this carbon dioxide will have big consequences, because even a small increase in the average temperature of the Earth can lead to drastic changes. For example, the Earth was on average only 5 degrees Celsius colder during the last ice age than it is today, but this has led to a significant change in regional temperature, the disappearance of a huge part of the flora and fauna, and the appearance of new species.
If global warming lead to the melting of all the ice sheets of Greenland and Antarctica, the level of the oceans will rise by 60 meters, compared with today's figures.
What causes great 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 cooler temperatures.
So, for example, according to the uplift and weathering hypothesis, when plate tectonics leads to the growth of mountain ranges, new unprotected rock appears on the surface. It is easily weathered and disintegrates when it enters 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.