The climate has changed in the world. Global warming: causes, manifestations and ways

• 1. Change in the frequency and intensity of precipitation. In general, the climate on the planet will become more humid. But the amount of precipitation will not spread evenly across the Earth. In regions that already receive enough rainfall today, their fallout will become more intense. And in regions with insufficient moisture, dry periods will become more frequent.
• 2. Sea level rise. During the twentieth century average level sea ​​level rose by 0.1-0.2 m. According to scientists, in the 21st century the sea level rise will be up to 1 m. In this case, coastal areas and small islands will be the most vulnerable. States such as the Netherlands, Great Britain, as well as the small island states of Oceania and the Caribbean will be the first to fall under the risk of flooding. In addition, high tides will become more frequent, and coastal erosion will increase.
• 3. Threat to ecosystems and biodiversity. There are forecasts for the extinction of up to 30-40% of plant and animal species, as their habitat will change faster than they can adapt to these changes.

With an increase in temperature by 1 degree, a change in the species composition of the forest is predicted. Forests are a natural carbon store (80% of all carbon in terrestrial vegetation and about 40% of carbon in soil). The transition from one type of forest to another will be accompanied by the release of a large amount of carbon.

4. Melting glaciers. The current glaciation of the Earth can be considered one of the most sensitive indicators of ongoing global changes. Satellite data show that since the 1960s there has been a decrease in the area of ​​snow cover by about 10%. Since the 1950s in the Northern Hemisphere, the area sea ​​ice decreased by almost 10-15%, and the thickness decreased by 40%. According to forecasts by experts from the Arctic and Antarctic Research Institute (St. Petersburg), in 30 years the Arctic Ocean will completely open from under the ice during the warm period of the year.

According to scientists, the thickness Himalayan ice melts at a rate of 10-15 m per year. At the current rate of these processes, two-thirds of the glaciers will disappear by 2060, and by 2100 all glaciers will have completely melted. The accelerated melting of glaciers poses a number of immediate threats to human development. For densely populated mountainous and foothill areas, avalanches, flooding or, conversely, a decrease in the full flow of rivers, and as a result, a reduction in fresh water reserves, are of particular danger.

5. Agriculture. The impact of warming on agricultural productivity is ambiguous. In some temperate areas, yields may increase with a small increase in temperature, but decrease with large changes in temperature. In tropical and subtropical regions, overall yields are projected to decrease.

The most serious blow can be dealt the poorest countries least prepared to adapt to climate change. According to the IPCC, by 2080 the number of people facing the threat of hunger could increase by 600 million, twice the number of people living in poverty today in sub-Saharan Africa.

• 6. Water consumption and water supply. One of the consequences climate change there may be a shortage of drinking water. In regions with arid climates (Central Asia, the Mediterranean, South Africa, Australia, etc.), the situation will be further aggravated due to a decrease in precipitation. Due to the melting of glaciers, the runoff of the largest water arteries Asia - Brahmaputra, Ganges, Yellow River, Indus, Mekong, Salween and Yangtze. The lack of fresh water will affect not only human health and agricultural development, but will also increase the risk of political divisions and conflicts over access to water resources.
• 7. Human health. Climate change, according to scientists, will lead to increased health risks for people, especially for the poorer segments of the population. Thus, a reduction in food production will inevitably lead to malnutrition and hunger. Abnormally high temperatures can exacerbate cardiovascular, respiratory and other diseases.

Rising temperatures may change the geographic distribution of various disease vector species. As temperatures rise, the ranges of heat-loving animals and insects (such as encephalitic mites and malaria mosquitoes) will spread further north, while the people inhabiting these areas will not be immune to new diseases.

According to environmentalists, humanity is unlikely to be able to prevent completely predictable climate change. However, it is within human power to mitigate climate change, to restrain the rate of temperature rise in order to avoid dangerous and irreversible consequences in the future. First of all, due to:

• - restrictions and reductions in the consumption of fossil carbon fuels (coal, oil, gas);
• - increasing the efficiency of energy consumption;
• - implementation of energy saving measures;
• - greater use of non-carbon and renewable energy sources;
• - development of new environmentally friendly and low-carbon technologies;
• - through prevention forest fires and reforestation, as forests are natural sinks of carbon dioxide from the atmosphere.

Destruction of the ozone layer. Ozone depletion is the separation of ozone molecules caused by stratospheric ozone depleting substances (OSNVs), natural processes (e.g. volcanic eruptions) or emitted (released) by human activities that contain chlorine (Cl) or bromine (Br); as well as methane or nitric oxide (I) - (N 2 O).

The ozone layer extends ten kilometers above the planet. And its thickness from this mark is only three or four hundred meters. It goes even higher, passing through the atmospheric layers, but its "working part", which is designed to prepare the respiratory mixture for all life on the planet, is only 10 kilometers and a little higher. Just at this height, airliners are very fond of flying, rockets make holes in it, leaving fuel in it. Gets this layer from our activities.

It's practically a chemical waste dump. Because of this, he is turned into a sieve. But the ozone layer is not only a workshop for the preparation of our breathing mixture, it also acts as a protector of all life on the planet's surface from the destructive uncleaned cosmic radiation. The bottom edge of the ozone layer is replenished from the surface reserves of the planet, mainly due to ocean evaporation. The "working part" is constantly under pressure, as it were, both from below and from above.

The most significant stages of the destruction of the ozone layer:

• - emissions (as a result of human activity, as well as as a result of natural processes on Earth, gases containing halogens (bromine and chlorine), i.e. substances that destroy the ozone layer, are emitted (released);
• - accumulation (emitted gases containing halogens accumulate (accumulate) in the lower atmospheric layers, and under the influence of wind and air flows move to regions that are not in direct proximity to the sources of such gas emissions);
• - movement (accumulated gases containing halogens move to the stratosphere with the help of air flows);
• - conversion (most of the gases containing halogens, under the influence of ultraviolet radiation from the Sun in the stratosphere, are converted into easily reacting halogen gases, as a result of which the destruction of the ozone layer in the polar regions of the globe is relatively more active);
• - chemical reactions(easily reacting halogen gases cause stratospheric ozone depletion; factor contributing to the reactions is polar stratospheric clouds);
• - removal (under the influence of air currents, easily reacting halogen gases return to the troposphere, where, due to the moisture and rain present in the clouds, they are separated, and thus completely removed from the atmosphere).

Types and impact of destructive substances. The main identified substances that deplete the ozone layer are:

• - chlorofluorocarbons (HFO or CFC);
• - partially halogenated chlorofluorocarbons (HHFO or HCFC);
• - partially halogenated bromofluorocarbons (HBFO);
• - 1,1,1 - trichloroethane (methyl chloroform);
• - bromochloromethane (BHM);
• - methyl bromide (MB);
• - carbon tetrachloride;
• - halons.

The main purposes of using substances that deplete the ozone layer are:

• - cooling units;
• - air conditioning devices;
• - warm air supply devices;
• - aerosols;
• - fire fighting systems and portable fire extinguishers;
• - insulating boards.

The impact on the ozone layer of substances that deplete the ozone layer characterizes the ozone depletion potential (ONP). The higher the ozone depletion potential, the higher the effect of the substance on the ozone layer. The highest ozone depletion potential is for halons (up to 12), and relatively low for partially halogenated chlorofluorocarbons (up to 0.01).

"Ozone Hole" - caused by the destruction of the ozone layer, especially low concentrations of ozone at the South Pole during the Arctic winter and spring. The area of ​​the "ozone hole" in last years was approximately 24,000,000 km 2, and in satellite photographs it looks like big hole. The thickness of the ozone layer in the region of the "ozone hole" is 100-150 DU (the normal thickness of the ozone layer is 300 DU).

consequences of destruction. As a result of the destruction of the ozone layer, an increased amount of solar UV-B radiation reaches the Earth, which has negative impact both on living beings (people, animals, vegetation) and on objects. Consequences of too “thin” ozone layer:

• - the endurance of various materials (for example, rubber) decreases and, at the same time, the duration of use of these materials;
• - living in the upper layers of the water die aquatic organisms(benthos);
• - Agricultural yields and fish catches are decreasing;
• - reduced immunity of the population against various diseases;
• - increases the possibility of skin cancer and eye cataracts (both in humans and animals), diseases of the lungs and upper respiratory tract.

The growth of the world's population. Of all the global problems that concern mankind, the issue of world population growth seems to be one of the main ones. The population size expresses the total result of all the economic, social and cultural activities of a person that make up his history. Demography is capable of providing only quantitative data, without describing the patterns of human development. Sergei Petrovich Kapitsa tried to fill this gap by creating a mathematical model of the world demographic process. The model shows that the rate of population growth does not depend on external conditions, explains the causes of the current sharp surge in the birth rate (“demographic transition”), and predicts that in the near future the population of the Earth will stop growing, stopping at about 14 billion people.

History has always described the past as a chain of events and processes in which we were primarily interested in what exactly happened, the qualitative side of the matter, and quantitative characteristics were of secondary importance. It was so, first of all, because the accumulation of facts and concepts must precede their quantitative characteristics. However, sooner or later they must penetrate history, and not as an illustration of this or that event, but as a way of a deeper understanding of the historical process. To do this, it is necessary to begin to consider history as a process of system development.

AT recent decades this so-called systemic approach has become widespread. It was developed first in physics to describe the behavior of systems of many particles, then it came to chemistry and biology, and later it began to be used to study social and economic phenomena. However, it was believed that it was not suitable for describing the development of mankind, because only by understanding the mechanism of demographic processes well, it is possible to explain them, measure their characteristics, and move from the particular to the general.

But it was for humanity as a whole that such an approach turned out to be unproductive. It was not clear what was to be measured, and there were no clear quantitative data. Already in the economy, fundamental difficulties arose in the quantitative comparison of heterogeneous concepts, such as labor and goods, raw materials and information, and in history only the course of time in the past is clearly traced.

However, there is one parameter that is as universal as time and applies to all eras - population. In life, we refer to it very often. Arriving in another city, we are interested in how many inhabitants there are, and having gathered in an unfamiliar country, we will certainly find out what its population is. In the 1930s, there were two billion people on the planet, but now there are almost six billion of us. But we rarely remember the population in the historical past. So, in 1700, there were ten times fewer people on Earth than today, and how many of them lived then in Russia, hardly anyone will immediately answer, although almost everyone knows the years of the reign of Peter I.

In a world where 21 people are born and 18 die every second, the world's population is increasing by 250,000 people every day, and almost all of this increase is in developing countries. The growth rate is so high - approaching ninety million a year - that it has come to be seen as a population explosion that could shake the planet. It is the continuous increase in the world's population that requires ever-increasing production of food and energy, consumption mineral resources and leads to ever-increasing pressure on the planet's biosphere. The image of rampant population growth, if naively extrapolated into the future, leads to disturbing predictions and even apocalyptic scenarios for the global future of humanity. However, it is clear that development in the foreseeable future - and this is precisely what is of greatest interest - can only be determined by correctly describing the past of mankind.

Humanity is currently undergoing a so-called demographic transition. This phenomenon consists in a sharp increase in the rate of population growth, then its equally rapid decrease and in the stabilization of the population. The demographic transition is accompanied by the growth of productive forces, the movement of significant masses of the population from villages to cities, and a sharp change in the age composition of the population. In today's interconnected and interdependent world, it will end in less than a hundred years and will pass much faster than in Europe, where a similar process began at the end of the 18th century. Now the transition covers most of the world's population, it has already ended in the so-called developed countries and now it is only in developing countries.

Another problem is that most of the population growth comes at the expense of developing countries, which creates pressure on natural and financial resources, making it difficult to raise living standards. In addition, the population of these countries is already experiencing a lack of food, and what will happen when the number doubles is difficult to predict. But in general, population growth in both developing and economically developed countries leads to degradation and depletion of resources.

The age structure of the population, which shows the percentage of the population or the number of inhabitants of both sexes that are at each particular age, is also alarming. There are three age categories: pre-productive (0-14 years old), productive (15-44 years old) and post-productive (over 45 years old). Looking at the age structure chart for countries with fast, slow, and zero population growth, we can see that developing countries with fast population growth have a high proportion of children under 15 compared to the proportion of older people over 65. In contrast, in economically developed countries with little or even zero population growth, the proportion of children is very small, while the proportion of people over the age of 65 is quite large.

This phenomenon will lead to the emergence of new problems. A heavy economic burden will fall on the young population of the planet, who will be forced to feed a large number of older people, which will be very difficult, because pensioners will not work. Retirees, which will be very numerous, will be able to use political pressure on working members of society and force them to earn more and pay higher taxes on pensions. Although at the same time, competition in the labor market will decrease. The shortage of workers will increase the level wages. Although people without education will experience economic hardship. Understanding this fact, in turn, will make young people think seriously about education, and thus the number of educated population will increase, which is always good for any state. At the same time, the birth rate will also decrease, because among the factors affecting the birth rate is the level of education (and the higher this level, the lower the birth rate).

At present, population regulation is seen as a real way to solve the problem of overpopulation of the planet. Governments in most developing countries seek to reduce fertility through a combination of economic development and family planning. As the country industrializes, there is a shift from rapid population growth to slower zero growth or even population decline. However, without rapid and sustainable economic development, many developing countries will be unable to make the demographic transition. Family planning programs include the creation of special counseling and medical services to help spouses decide how many and when to have children.

Climate is the average weather value for several decades, typical for a certain region. Weather differs from climate mainly in that it characterizes the short-term state of the atmosphere in a particular locality. Interestingly, some characteristics can describe both weather and climate, for example, Atmosphere pressure, wind speed and humidity.

The climate, like the weather, changes, but much more slowly, it takes thousands of years, and sometimes entire eras, to change the climate. Climate change is fueled by uneven amounts of heat received from the sun. Man also plays an important role in shaping the climate. Rapid industrial activity on Earth, the use of fossil fuels, the development of transport, all these are the causes of climate change. The fact is that the atmosphere accumulates a lot of carbon dioxide, which contributes to additional heating of the planet.

Scientists now view Earth's climate change as global problem humanity. In addition to the fact that climate change moves naturally, rash human activities add additional problems.

Climate change is not only about rising temperatures, this process has a much more global significance. At this moment, all geosystems are being rebuilt on Earth, and the increase in temperature is only a small echo of all the consequences. Researchers have noted a rise in the water level on the planet, glaciers are melting, and precipitation is becoming irregular. Increasingly, natural disasters occur and spread more and more dangerous diseases. All this poses a danger not only to the natural system and the world economy, but also to the existence of man. Over the past hundred years, the temperature in the Earth's atmosphere has risen by two-thirds of a degree and it continues to rise.

Therefore, it is worth talking not only about global warming, but also about all possible scenarios of climate change. Now the Earth is in an interglacial period, but no one knows for sure how long this period can last. Scientists are also considering such an option as glaciation. This can happen under the influence of astronomical factors, if:

• The earth's axis will change its tilt.
• The Earth will deviate from its orbit, moving away from the Sun.
• Uneven flow of solar heat to the surface of the planet.

Geological factors are also considered, such as the activity of volcanoes, mountain formations, and the movement of continental plates.

The variability of the World Ocean is the main indicator of changes in the overall climate picture. Also, climate change can occur due to the interaction of water and the atmospheric layer. With the help of water, heat circulates throughout the planet, which can have a strong impact on climatic zones.

The earth has a phenomenal property - climate memory. Changes in climate are not only the consequences of its changes, under the influence of certain factors, but also the whole history of its changes. It is possible to trace it on simple example: when a drought lasts for several years in the area, the reservoirs begin to dry up, the size of the desert increases. As time goes on, the rainfall in this place decreases. This is an indicator that not only nature is changing under the influence of climate change, but nature has an impact on the climate through its changes.

Drivers of climate change

Under the influence of changes in the atmosphere and the surface of the planet, the climate is changing. There are two types of factors: anthropogenic and non-anthropogenic.

So what contributes to climate change when we are talking about non-anthropogenic conditions:

• Tectonics of lithospheric plates. It's no secret that for pretty for a long time The continents are moved by tectonic plates. Thus, new seas and oceans are created, mountains collapse or grow: a surface is created, where the climate is subsequently formed. As the facts showed, the last ice age extended the movement of two plates, which collided and formed the Isthmus of Panama, which prevented the mixing of the waters of the two oceans, which is why the glaciation period lasted longer.
• solar radiation. Without the light of the Sun, it would be impossible to form conditions suitable for life, and of course, the celestial body affects all processes occurring on a living planet, including the formation of climatic conditions. In the aspect of a very long period, now the Sun has become brighter and gives much more heat. Such a long process also affects the Earth. According to the researchers, at an early stage in the formation of life on Earth, the Sun was so inactive that the water was in a state of ice. Even in short time periods, one can trace the change in the activity of the luminary. For example, at the beginning of the last century, warming was noticed, which is associated with short-term activity of the Sun. The influence of a star on the Earth's atmosphere is not fully understood, but it is not related to the changes that occur on the Fiery Planet itself.
• Milankovitch cycles. Changes in the trajectory of the earth's orbit affect the state of the climate, and are very similar in their actions to solar forcing. The change in the planet's flight path is a consequence of the uneven distribution sun rays across the globe. This phenomenon is called the Milankovitch cycle. Which is a consequence of the connection of the Earth and the Moon with other planets, so that they can be calculated with all the details. The result of such cycles can be considered a change in the size of the Sahara desert in small periods of time.
• Volcanism. As scientific studies show, one powerful volcanic eruption is followed by a cooling in the area for several years. Despite the rarity of eruptions, volcanoes have a significant impact on the features of climate formation for many thousands of years and affect the extinction or preservation of entire species. Initially, it was thought that the decrease in temperature after the eruption was due to volcanic dust, as it can prevent solar radiation from reaching earth's atmosphere. But, as it turned out, the bulk of the dust dissipates within six months.

All of these non-anthropogenic factors explain how and why natural climate change occurs.

Anthropogenic factors influencing climate change

Anthropogenic factors are the consequences of human activities that affect environment, and hence to climatic conditions too. For many years there has been a debate about how much impact human actions have on the atmosphere. But the main problem cannot be denied, in view of its obviousness. Due to the consumption of a huge amount of combustible substances as fuel, a large amount of carbon dioxide accumulates in the atmosphere. Also the cement industry, Agriculture, cattle breeding, deforestation, all this affects climate change to one degree or another, and leads mainly to global warming.

Global warming is an increase in the average temperature value, which entails a change climatic zones, and this, in turn, may adversely affect the continued existence of favorable conditions for humanity.

Causes of global warming

With reliable accuracy, no expert can say what exactly causes global warming in the first place. However, most scientists are on the side of the version where the main cause of warming is man, or rather, his booming industry. There is strong evidence that, if before the industrial boom, the increase in the average temperature on Earth by one tenth of a degree occurred once every millennium, now the temperature level is growing inexorably over several decades. Such a rapid increase in indicators will lead to unthinkable consequences.

An increase in the average temperature on Earth will lead to a change in climatic zones, which will lead to the melting of glaciers in the Northern and south poles, and because of this, the level of the oceans will rise. Global warming is already affecting the animal world. Some species die, some change their usual habitats. Also, this cataclysm can lead to an increase in the number of infectious diseases, allergies and asthma, as heat beneficial effect on the spread of harmful bacteria. Global warming will negatively affect many industries human life, primarily on the economy, tourism and agriculture, and will make many countries uninhabitable.

To prevent global warming, it is necessary to unite all countries. It is obvious that an excellent solution to the problem will be the economical use of energy resources and a limited amount of emissions of gases into the atmosphere. The use of inexhaustible natural resources, such as solar panels, wind or water power plants, is actively discussed.

Anthropogenic includes not only global warming, but also climate change in general, as a result of excessive deforestation, agriculture and the use of natural resources Earth.

Interaction of factors

The influence of anthropogenic and non-anthropogenic factors on the climate, together, is measured by the generally accepted value of W / m 2, this is the level of radiation heating of the atmospheric layer. The total balance of radiation in the atmosphere is about 3 W / m 2, human impact from this figure is no more than 1%, and an increase in greenhouse gases by 2% (see).

The cycle of climate change

Back in the late 19th century, Russian scientists put forward the idea that warm and cold climate alternate in the time interval of 30-40 years. An example of a change in the level of the World Ocean is given as evidence.

Climate skepticism

Despite the vast amount of evidence that global warming is around the corner, there are skeptics who reject it. The mood of skepticism is present in many countries of the world, which prevents making important political decisions to prevent global warming, which exposes the existence of life on Earth great danger, because no one can say for sure how catastrophic consequences warming will bring with it.

Sun. Due to the uneven heating of the earth's surface, winds and ocean currents arise. Increased solar activity is accompanied by magnetic storms and a marked rise in global air temperature. The climate also depends on changes in the Earth's orbit, its magnetic field. The seismic activity of the planet increases, volcanic activity is activated, the outlines of the continents and oceans are changing. All of the above are natural causes of climate change. Until some time, only these factors were decisive. This also includes long-term cycles such as ice ages. Focusing on solar and volcanic activity, given that the first leads to an increase in temperature and the second to a decrease, one can find an explanation for half of the temperature shifts before 1950. But over the past two centuries, another factor has been added to the natural causes of the ongoing changes. It is anthropogenic, i.e. resulting from human activity. Its main impact is a progressive greenhouse effect. Its influence is estimated to be 8 times stronger than the influence of fluctuations in solar activity. This is what scientists, the public and heads of state are so concerned about. The greenhouse effect is easy to observe in greenhouses or greenhouses. The inside of these rooms is much warmer and more humid than the outside. The same thing happens on a global scale. Solar energy passes through the atmosphere and heats the Earth's surface. But the thermal energy that the planet radiates cannot penetrate into it in a timely manner, because. the atmosphere traps it, like polyethylene in a greenhouse. This is where the greenhouse effect comes in. The reason for this phenomenon is the presence of gases in the atmosphere of the planet, which are called "greenhouse" or "greenhouse". Greenhouse gases have been present in the atmosphere since its formation. They amounted to only about 0.1%. This turned out to be enough for a natural greenhouse effect to occur, affecting the heat balance of the Earth and providing a level that is suitable. If not for him average temperature the Earth's surface would be 30°C lower, i.e. not + 14 ° C, as on this moment, and -17оС. The natural greenhouse effect and the water cycle in nature support life on the planet. The anthropogenic increase in greenhouse gases in the atmosphere leads to an increase in this phenomenon and a violation of the heat balance on Earth. This has been happening for the last two hundred years of the development of civilization and is happening now. The industry it created, automobile exhausts and much more emit a huge amount of greenhouse gases into the atmosphere, to be exact, about 22 billion tons per year. As a result, global warming is occurring, which is causing a change average annual temperature air. Over the past hundred years, the average temperature of the Earth has risen by 1°C. It doesn't seem like much. But this degree turned out to be quite sufficient for the melting of the polar ice and a noticeable rise in the level of the world ocean, which naturally leads to certain consequences. There are processes that can be easily started, but subsequently difficult to stop. For example, the result of the melting of the subarctic permafrost was the release of a huge amount of methane into the atmosphere of the planet. The greenhouse effect is intensifying. BUT fresh water melting ice changes the warm current of the Gulf Stream, which in turn will change the climate of Europe. It is clear that all these processes cannot be local. This will affect all of humanity. The moment has come to understand that the planet is a living being. It breathes and develops, radiates and interacts with other elements of the Universe. It is impossible to deplete its bowels and pollute the ocean, it is impossible for the sake of dubious pleasure to cut down virgin forests and divide the indivisible!

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Ecology is a science that few people pay attention to. People have been accustomed through millennia of cultural activity to think that the planet is so huge, and its properties are so constant, that you can do anything you want: the Earth will recover. But the human impact on nature and climate in the last couple of hundred years has become so intense that serious climate changes can already be observed. In the future, this process promises to only intensify.

Instruction

Weather reports that clearly illustrate the state of affairs on the planet today cannot but surprise. You can constantly hear about all kinds of anomalies: “the highest temperature in March in the last hundred years”, “precipitation in July for the entire time of observations”, “anomalously late winter” ... In December and January in Russia in cities where it always lay in this snow time, you can see clean streets. But snowfalls paralyze neighboring countries, whose climate is usually much warmer. Droughts that have severely hampered agriculture in some regions, combined with heavy rains and floods in others, are suggesting that climate change is something more than just not normal. warm winter. The entire economy of mankind depends on the climate. The more serious its changes, the less people are ready for them, the higher the likelihood of famine and major man-made disasters.

Human influence on climate can be divided into two categories. The first one is local impact. This is soil erosion, drainage of swamps, destruction certain types flora and fauna, river and air pollution, land depletion and other similar types of influence. The second category is global change climate. The totality of factors from the first group eventually accumulates and reaches a critical mass, the influence extends beyond a certain region of the planet and changes it as a whole.

Massive deforestation and an increase in carbon dioxide in the atmosphere have led to the so-called "greenhouse effect", due to which the average air temperature on the planet has risen. Because of this, they began to melt intensively polar ice. This, in turn, leads to the fact that the water level in the World Ocean rises, and cold streams from melting ice affect warm currents - the Gulf Stream especially suffers from this, thanks to which many countries in Europe, as well as all Caribbean states, can boast of a rather mild climate.

The geological age of our planet is approximately 4.5 billion years. During this period, the Earth has changed dramatically. The composition of the atmosphere, the mass of the planet itself, the climate - at the beginning of existence, everything was completely different. The red-hot ball very slowly became the way we are used to seeing it now. Tectonic plates collided, forming new mountain systems. On a gradually cooling planet, seas and oceans formed. Continents appeared and disappeared, their shape and size changed. The earth began to rotate more slowly. The first plants appeared, and then life itself. Accordingly, over the past billions of years, cardinal changes have taken place on the planet in moisture circulation, heat circulation and atmospheric composition. Climate change has occurred throughout the existence of the Earth.

Holocene Epoch

Holocene - part Quaternary period In other words, this is an era that began approximately 12 thousand years ago and continues to the present. The Holocene began with the end ice age, and since then climate change on the planet has been going in the direction of global warming. This era is often referred to as the interglacial, since there have already been several ice ages in the entire climatic history of the planet.

The last global cooling occurred approximately 110,000 years ago. About 14 thousand years ago, warming began, gradually covering the entire planet. Glaciers, which at that time covered most of northern hemisphere began to melt and disintegrate. Naturally, all this did not happen overnight. For a very long period, the planet was shaken by strong temperature fluctuations, the glaciers either advanced or retreated again. All this also affected the level of the World Ocean.

Holocene periods

During numerous studies, scientists decided to divide the Holocene into several time periods depending on the climate. Approximately 12-10 thousand years ago, the ice sheets disappeared, the post-glacial period began. In Europe, the tundra began to disappear, it was replaced by birch, pine and taiga forests. This time is called the Arctic and Subarctic period.

Then came the boreal era. The taiga pushed the tundra further north. In southern Europe there were broadleaf forests. During this time, the climate was predominantly cool and dry.

Approximately 6 thousand years ago, the Atlantean era began, during which the air became warm and humid, much warmer than today. This period of time is considered the climatic optimum of the entire Holocene. Half was covered with birch forests. Europe abounded in a great variety of heat-loving plants. At the same time, the length temperate forests was much further north. Dark coniferous forests grew on the shores of the Barents Sea, and the taiga reached Cape Chelyuskin. On the site of the modern Sahara there was a savannah, and the water level in Lake Chad was 40 meters higher than the modern one.

Then climate change happened again. A cold snap set in, lasting about 2,000 years. This period of time is called subboreal. Mountain ranges in Alaska, Iceland, in the Alps acquired glaciers. Landscape zones have shifted closer to the equator.

Approximately 2.5 thousand years ago, the last period of the modern Holocene, the Subatlantic, began. The climate of this era became cooler and wetter. Peat bogs began to appear, the tundra gradually began to press on the forests, and the forests on the steppes. Around the 14th century, the cooling of the climate began, leading to the Little Ice Age, which lasted until the middle of the 19th century. At this time, invasions of glaciers were recorded in the mountain ranges of Northern Europe, Iceland, Alaska and the Andes. AT different points the globe The climate has not changed synchronously. The causes of the onset of the Little Ice Age are still unknown. According to scientists, the climate could change due to increases in volcanic eruptions and a decrease in the concentration of carbon dioxide in the atmosphere.

Start of meteorological observations

The first appeared at the end of the 18th century. Since that time, constant monitoring of climatic fluctuations has been carried out. It can be reliably stated that the warming that began after the Little Ice Age continues to the present.

Since the end of the 19th century, an increase in the average global temperature of the planet has been recorded. In the middle of the 20th century there was a slight cooling, which did not affect the climate in general. Since the mid-1970s, it has become warmer again. According to scientists, over the past century, the global temperature of the Earth has increased by 0.74 degrees. Greatest growth this indicator has been recorded in the last 30 years.

Climate change invariably affects the state of the oceans. An increase in global temperature leads to the expansion of water, and hence to an increase in its level. There are also changes in the distribution of precipitation, which, in turn, can affect the flow of rivers and glaciers.

According to observations, the level of the World Ocean over the past 100 years has risen by 5 cm. Scientists associate climate warming with an increase in the concentration of carbon dioxide and a significant increase in the greenhouse effect.

climate-forming factors

Scientists have conducted many archaeological studies and came to the conclusion that the climate of the planet has changed dramatically more than once. Many hypotheses have been put forward in this regard. According to one of the opinions, if the distance between the Earth and the Sun remains the same, as well as the speed of rotation of the planet and the angle of the axis, then the climate will remain stable.

External drivers of climate change:

1. The change in the solar radiation leads to the transformation of solar radiation fluxes.
2. Movements of tectonic plates affect land orography as well as ocean levels and circulation.
3. The gas composition of the atmosphere, in particular the concentration of methane and carbon dioxide.
4. Change in the tilt of the Earth's axis of rotation.
5. Changes in the parameters of the planet's orbit with respect to the Sun.
6. Terrestrial and space catastrophes.

Human activity and its impact on climate

The causes of climate change are connected, among other things, with the fact that humanity has intervened in nature throughout its existence. Deforestation, plowing, etc. lead to transformations in the humidity and wind regimes.

When people make changes to surrounding nature By draining swamps, creating artificial reservoirs, cutting down forests or planting new ones, building cities, etc., the microclimate changes. The forest strongly influences the wind regime, which determines how the snow cover will fall, how much the soil will freeze.

Green spaces in cities reduce the impact of solar radiation, increase air humidity, reduce the temperature difference in the daytime and evening, and reduce air dustiness.

If people cut down forests on the hills, then in the future this leads to a washout of the soil. Also, the decrease in the number of trees reduces the global temperature. However, this means an increase in the concentration of carbon dioxide in the air, which is not only not absorbed by trees, but is also additionally released during the decomposition of wood. All this compensates for the decrease in global temperature and leads to its increase.

Industry and its impact on the climate

The causes of climate change lie not only in general warming, but also in the activities of mankind. People have increased the concentration in the air of substances such as carbon dioxide, nitrous oxide, methane, tropospheric ozone, chlorofluorocarbons. All this ultimately leads to an increase in the greenhouse effect, and the consequences may be irreversible.

Every day, industrial plants emit many hazardous gases into the air. Transportation is used everywhere, polluting the atmosphere with its emissions. A lot of carbon dioxide is formed when oil and coal are burned. Even agriculture causes considerable damage to the atmosphere. Approximately 14% of all emissions come from this area. This includes plowing fields, burning waste, burning the savannah, manure, fertilizers, animal husbandry, etc. The greenhouse effect helps maintain the temperature balance on the planet, but human activity enhances this effect at times. And this can lead to disaster.

Why should we be afraid of climate change?

97% of the world's climatologists are sure that everything has changed dramatically in the last 100 years. And the main problem climate change is an anthropogenic activity. It’s impossible to say for sure how serious this situation is, but there are many reasons for concern:

UN convention

The governments of most countries on the planet are seriously afraid of what the consequences of climate change could be. Created over 20 years ago international treaty- Framework Convention on Climate Change. All possible measures to prevent global warming are considered here. Now the convention has been ratified by 186 countries, including Russia. All participants are differentiated into 3 groups: industrially with economic development and developing countries.

The UN Convention on Climate Change is fighting to reduce the growth of greenhouse gases in the atmosphere and further stabilize indicators. This can be achieved either by increasing the sink of greenhouse gases from the atmosphere, or by reducing their emissions. The first option requires a large number of young forests that will absorb carbon dioxide from the atmosphere, and the second option will be achieved if the consumption of fossil fuels is reduced. All ratified countries agree that the world is undergoing global climate change. The UN is ready to do everything possible to mitigate the consequences of the impending strike.

Many countries participating in the convention have come to the conclusion that joint projects and programs will be the most effective. Currently, there are more than 150 such projects. Officially, there are 9 such programs in Russia, and more than 40 unofficially.

At the end of 1997, the Convention on Climate Change signed the Kyoto Protocol, which stipulated that countries with economies in transition undertake obligations to reduce greenhouse gas emissions. The protocol has been ratified by 35 countries.

Our country also took part in the implementation of this protocol. Climate change in Russia has doubled the number of natural disasters. Even if we take into account that boreal forests are located on the territory of the state, they cannot cope with all greenhouse gas emissions. It is necessary to improve and increase forest ecosystems, to carry out large-scale measures to reduce emissions from industrial enterprises.

Predictions of the effects of global warming

The essence of climate change in the last century is global warming. According to the worst forecasts, further irrational activities of mankind can increase the temperature of the Earth by 11 degrees. Climate change will be irreversible. The rotation of the planet will slow down, many species of animals and plants will die. The level of the World Ocean will rise so much that many islands and most of the coastal areas will be flooded. The Gulf Stream will change its course, leading to a new Little Ice Age in Europe. There will be widespread cataclysms, floods, tornadoes, hurricanes, droughts, tsunamis, etc. The melting of the ice of the Arctic and Antarctica will begin.

For humanity, the consequences will be catastrophic. In addition to the need to survive in conditions of strong natural anomalies people will have many other problems. In particular, the number of cardiovascular diseases, respiratory diseases, psychological disorders will increase, outbreaks of epidemics will begin. There will be an acute shortage of food and drinking water.

What to do?

To avoid the effects of climate change, the first step is to reduce the level of greenhouse gases in the atmosphere. Humanity should switch to new energy sources, which should be low-carbohydrate and renewable. Sooner or later, this issue will be acute for the world community, since the resource currently used - mineral fuel - is non-renewable. Someday scientists will have to create new, more efficient technologies.

It is also necessary to reduce the level of carbon dioxide in the atmosphere, and only the restoration of forest areas can help with this.

It is required to apply maximum efforts to stabilize the global temperature on Earth. But even if this fails, humanity must try to achieve minimal effects of global warming.

Changing of the climate- fluctuations in the climate of the Earth as a whole or its individual regions over time, expressed in statistically significant deviations of weather parameters from long-term values ​​over a period of time from decades to millions of years. Changes in both the average values ​​of weather parameters and changes in the frequency of extreme events are taken into account. weather events. The study of climate change is the science of paleoclimatology. The cause of climate change is dynamic processes on the Earth, external influences such as fluctuations in the intensity of solar radiation, and, more recently, human activities. Changes in the modern climate (in the direction of warming) are called global warming.

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Subtitles

Manifestations of climate change

Weather is the state of the lower layers of the atmosphere in given time, in this place. The weather is a chaotic non-linear dynamic system. Climate is the average state of the weather and is predictable. The climate includes indicators such as average temperature, rainfall, sunny days and other variables that can be measured at any given location. However, there are also processes on Earth that can affect the climate.

glaciation

• change in size, relief and relative position continents and oceans,
• change in the luminosity of the Sun,
• changes in the parameters of the Earth's orbit and axis,
• changes in the transparency and composition of the atmosphere, including changes in the concentration of greenhouse gases (CO 2 and CH 4),
• change in the reflectivity of the Earth's surface (albedo),
• change in the amount of heat available in the depths of the ocean, [ ]

Non-anthropogenic factors and their impact on climate change

Plate tectonics

Over long periods of time, tectonic movements plates move continents, form oceans, create and destroy mountain ranges, that is, create a surface on which there is a climate. Recent studies show that tectonic movements aggravated the conditions of the last ice age: about 3 million years ago, the North and South American plates collided, forming the Isthmus of Panama and closing the way for direct mixing of the waters of the Atlantic and Pacific oceans.

solar radiation

On shorter time intervals, changes in solar activity are also observed: an 11-year solar cycle and longer secular and millennial modulations. However, the 11-year cycle of sunspot occurrence and disappearance is not tracked explicitly in the climatological data. Changes in solar activity are considered an important factor in the onset of the Little Ice Age, as well as some of the warming observed between 1900 and 1950. The cyclical nature of solar activity is not yet fully understood; it differs from those slow changes that accompany the development and aging of the Sun.

Milankovitch cycles

In the course of its history, the planet Earth regularly changes the eccentricity of its orbit, as well as the direction and angle of inclination of its axis, which leads to a redistribution of solar radiation on the Earth's surface. These changes are called "Milankovitch cycles", they are predictable with high accuracy. There are 4 Milankovitch cycles:

1. Precession- rotation of the earth's axis under the influence of the attraction of the moon, as well as (to a lesser extent) the sun. As Newton found out in his Elements, the oblateness of the Earth at the poles leads to the fact that gravity external bodies rotates the earth's axis, which describes a cone with a period (according to modern data) of approximately 25,776 years, as a result of which the seasonal intensity amplitude changes solar flow in the northern and southern hemispheres of the Earth;
2. Nutation- long-term (so-called secular) fluctuations in the angle of inclination of the earth's axis to the plane of its orbit with a period of about 41,000 years;
3. Long-term fluctuations in the eccentricity of the Earth's orbit with a period of about 93,000 years;
4. Movement of the perihelion of the Earth's orbit and the ascending node of the orbit with a period of 10 and 26 thousand years, respectively.

Since the described effects are periodic with a non-multiple period, fairly long epochs regularly occur when they have a cumulative effect, reinforcing each other. They are considered the main reasons for the alternation of glacial and interglacial cycles of the last ice age, including explaining the Climatic Optimum of the Holocene. The result of the precession of the earth's orbit are and less major changes, such as the periodic increase and decrease in the area of ​​the Sahara Desert.

Volcanism

One strong volcanic eruption can affect the climate, causing a cooling spell lasting several years. For example, the eruption of Mount Pinatubo in 1991 significantly affected the climate. The giant eruptions that form the largest igneous provinces occur only a few times every hundred million years, but they affect the climate for millions of years and cause the extinction of species. Initially, it was assumed that the cause of the cooling was volcanic dust thrown into the atmosphere, since it prevents solar radiation from reaching the Earth's surface. However, measurements show that most of the dust settles on the Earth's surface within six months.

Volcanoes are also part of the geochemical carbon cycle. For many geological periods carbon dioxide was released from the bowels of the Earth into the atmosphere, thereby neutralizing the amount of CO 2 removed from the atmosphere and bound sedimentary rocks and other geological sinks of CO 2 . However, this contribution is not comparable in magnitude to the anthropogenic emission of carbon monoxide, which, according to the US Geological Survey, is 130 times greater than the amount of CO 2 emitted by volcanoes.

Anthropogenic impact on climate change

Anthropogenic factors include human activities that change the environment and affect the climate. In some cases the causal relationship is direct and unambiguous, such as in the effect of irrigation on temperature and humidity, in other cases the relationship is less clear. Various hypotheses of human influence on climate have been discussed over the years. In the late 19th century, in the western United States and Australia, for example, the "rain follows the plow" theory was popular.

The main problems today are: the increasing concentration of CO 2 in the atmosphere due to fuel combustion, aerosols in the atmosphere that affect its cooling, and the cement industry. Other factors such as land use, depletion of the ozone layer, livestock and deforestation also affect the climate.

Interaction of factors

The impact on the climate of all factors, both natural and anthropogenic, is expressed by a single value - radiative heating of the atmosphere in W/m 2 . [ ] Volcanic eruptions, glaciations, continental drift and the shift of the Earth's poles are powerful natural processes that affect the Earth's climate. On a scale of several years, volcanoes may play a major role. As a result of the 1991 eruption of the Pinatubo volcano in the Philippines, so much ash was thrown to a height of 35 km that the average level of solar radiation decreased by 2.5 W / m 2. However, these changes are not long-term, particles settle down relatively quickly. On a millennium scale, the climate-determining process is likely to be the slow movement from one ice age to the next.

On a scale of several centuries, in 2005 compared to 1750 there is a combination of multidirectional factors, each of which is much weaker than the result of an increase in the concentration of greenhouse gases in the atmosphere, estimated as a warming of 2.4-3.0 W/m 2 . The human influence is less than 1% of the total radiation balance, and the anthropogenic increase in the natural greenhouse effect is approximately 2%, from 33 to 33.7 degrees C. Thus, the average air temperature at the Earth's surface has increased since the pre-industrial era (since about 1750) by 0.7 °С

The cycle of climate change

35-45 year cycles of climate change

The alternation of cool-wet and warm-dry periods in the interval of 35-45 years, put forward at the end of the 19th century. Russian scientists E. A. Brikner and A. I. Voeikov. Subsequently, these scientific provisions were substantially developed by A.V. Shnitnikov in the form of a coherent theory of intra- and multi-century climate variability and the general moisture content of the continents of the Northern Hemisphere. The system of evidence is based on facts about the nature of changes in the mountain glaciation of Eurasia and North America, filling levels of inland water bodies, including the Caspian Sea, the level of the World Ocean, variability of ice conditions in the Arctic, historical information about the climate. .