Climate change on earth. Tectonics of lithospheric plates

Introduction

1. Causes of climate change

2. The concept and essence of the greenhouse effect

3. Global warming   and the impact on him of a person

4. Consequences of global warming

5. Measures necessary to prevent global warming

Conclusion

Bibliography

Introduction

The world is getting warmer, and humanity is largely responsible for this, experts say. But many factors affecting climate change have not yet been studied, while others have not been studied at all.

Some of the arid places in Africa have become even drier over the past 25 years. Rare lakes that bring water to people dry up. Sandy winds are intensifying. The rains stopped there in the 1970s. The problem of drinking water is becoming more acute. According to computer models, such areas will continue to dry out and become completely uninhabitable.

Coal mining is spread all over the planet. A huge amount of carbon dioxide (CO 2) is emitted into the atmosphere when coal is burned. As developing countries follow in the footsteps of their industrial neighbors, the amount of CO 2 will double during the 21st century.

Most experts, studying the complexity of the Earth’s climate system, associate the increase in global temperature and future climate change with an increase in CO 2 in atmospheric air.

Life thrives on the planet for about four billion years. During this time, climate fluctuations were radical, from the ice age - which lasted 10,000 years - to the era of rapid warming. With each change, an indefinite number of species of life forms have changed, developed and survived. Others have weakened or simply become extinct.

Now, many experts believe that humanity is endangering the global ecological system due to global warming caused by the so-called greenhouse effect. Evaporation of civilization products in the form of greenhouse gases, such as carbon dioxide (CO 2), delayed enough heat reflected from the earth's surface, so that the average temperature at the earth's surface increased by half a degree Celsius during the 20th century. If this direction of the modern industry continues, the climate system will change everywhere - melting ice, raising sea levels, destroying plants by droughts, turning areas into deserts, moving green areas.

But this may not be. Climate on the planet depends on a combination of many factors interacting separately with each other and in complex ways that are not yet fully understood. It is possible that the warming observed during the last century was due to natural fluctuations, despite the fact that its speeds were much higher than those observed during the last ten centuries. Moreover, computer simulations may not be accurate.

However, in 1995, after long years of intensive study, the International Conference on Climate Change, sponsored by the United Nations, tentatively concluded that “many proofs show that humanity’s influence on global climate   are huge. " The extent of these influences, as experts note, is unknown, since the key factor, including the degree of the impact of clouds and oceans on the change in global temperature, is not determined. It may take a decade or more to investigate these uncertainties.

In the meantime, much is already known. And although the specifics of the circumstances of human economic activity remain unclear, our ability to change the composition of the atmosphere is undeniable.

The purpose of this work is to study the problem of climate change on Earth.

The objectives of this work:

1. to study the causes of climate change;

2. to consider the concept and essence greenhouse effect;

3. to define the concept of “global warming” and show the influence of humanity on it;

4. show the consequences awaiting humanity as a result of global warming; 5. Consider the measures needed to prevent global warming.

1. CAUSES OF CLIMATE CHANGE

What is global climate change and why is it often called “global warming”?

It is impossible to disagree with the fact that the climate on Earth is changing and this is becoming a global problem for all mankind. Fact global change   climate is confirmed by scientific observations and is not disputed by most scientists. And yet around this topic are ongoing discussions. Some use the term "global warming" and make apocalyptic predictions. Others predict the onset of a new “ice age” - and also make apocalyptic predictions. Still others consider climate change natural, and evidence from both sides about the inevitability of the catastrophic effects of climate change - controversial ... Try to figure it out ...

What evidence is there of climate change?

They are well known to everyone (this is noticeable without instruments): an increase in global average temperature (milder winters, hotter and drier summer months), melting of glaciers and rising sea levels, as well as increasingly frequent and increasingly destructive typhoons and hurricanes, floods in Europe and droughts in Australia ... (see also “5 prophecies about climate that have come true”). And in some places, for example, in the Antarctic, a cooling is observed.

If the climate has changed before, why has it become a problem now?

Indeed, the climate of our planet is constantly changing. Everyone knows about the glacial periods (they are small and large), with the global flood, etc. According to geological data, the average world temperature in different geological periods ranged from +7 to +27 degrees Celsius. Now the average temperature on Earth is about +14 o C and is still quite far from the maximum. So, what are scientists, heads of state and the public concerned about? In short, the concern is that, to the natural causes of climate change, which have always been added, another factor is added - anthropogenic (the result of human activity), whose influence on climate change, according to a number of researchers, is becoming stronger with each passing year.

What are the causes of climate change?

The main driving force of climate is the sun. For example, uneven heating of the earth’s surface (stronger at the equator) is one of the main causes of winds and ocean currents, and periods of increased solar activity   accompanied by warming and magnetic storms.

In addition, the climate is influenced by changes in the Earth's orbit, its magnetic field, the size of continents and oceans, and volcanic eruptions. These are all natural causes of climate change. Until recently, they, and only they, have defined climate change, including the beginning and end of long-term climate cycles, such as glacial periods. Solar and volcanic activity can be attributed to half of the temperature changes before 1950 (solar activity leads to an increase in temperature, and volcanic activity - to a decrease).

Recently, another one has been added to the natural factors - anthropogenic, i.e. caused by human activity. The main anthropogenic impact is the increased greenhouse effect, whose influence on climate change over the past two centuries is 8 times higher than the effect of changes in solar activity.

2. CONCEPT AND ESSENCE OF GREENHOUSE EFFECT

The greenhouse effect is the delay of the planet’s thermal radiation by the Earth’s atmosphere. The greenhouse effect was observed by any of us: in greenhouses or greenhouses, the temperature is always higher than outside. The same is observed on the scale of the Earth: solar energy, passing through the atmosphere, heats the Earth’s surface, but the thermal energy emitted by the Earth cannot escape back into space, as the Earth’s atmosphere delays it, acting like polyethylene in a greenhouse: it transmits short light waves from the Sun to the Earth and delays long thermal (or infrared) waves emitted by the Earth’s surface. There is a greenhouse effect. The greenhouse effect occurs due to the presence of gases in the Earth’s atmosphere, which have the ability to trap long waves. They are called "greenhouse" or "greenhouse" gases.

Greenhouse gases have been present in the atmosphere in small amounts (about 0.1%) since its formation. This amount was enough to maintain, due to the greenhouse effect, the heat balance of the Earth at a level suitable for life. This is the so-called natural greenhouse effect, if its average temperature of the Earth’s surface were 30 ° C lower, i.e. not + 14 ° С, as it is now, but -17 ° С.

The natural greenhouse effect does not threaten neither the Earth nor humanity, since the total amount of greenhouse gases was maintained at the same level due to the cycle of nature, moreover, we owe it to life.

But an increase in the concentration of greenhouse gases in the atmosphere leads to an increase in the greenhouse effect and disruption of the thermal balance of the Earth. That is what happened in the last two centuries of civilization. Coal-fired power plants, car exhausts, factory pipes and other sources of pollution created by mankind emit about 22 billion tons of greenhouse gases into the atmosphere per year.

What gases are called "greenhouse"?

The most famous and common greenhouse gases are water vapor   (H 2 O), carbon dioxide   (CO 2), methane   (CH 4) and laughing gas   or nitrous oxide (N 2 O). These are direct greenhouse gases. Most of them are formed in the process of burning fossil fuels.

In addition, there are two more groups of direct-acting greenhouse gases, this halocarbons   and sulfur hexafluoride   (SF6). Their emissions to the atmosphere are associated with modern technology and industrial processes (electronics and refrigeration equipment). Their amount in the atmosphere is completely insignificant, but they have an impact on the greenhouse effect (the so-called global warming potential / GWP), tens of thousands of times stronger than CO 2.

Water vapor is the main greenhouse gas responsible for more than 60% of the natural greenhouse effect. An anthropogenic increase in its concentration in the atmosphere has not yet been noted. However, an increase in the temperature of the Earth, caused by other factors, increases the evaporation of ocean water, which can lead to an increase in the concentration of water vapor in the atmosphere and - to an increase in the greenhouse effect. On the other hand, clouds in the atmosphere reflect direct sunlight, which reduces the flow of energy to the Earth and, accordingly, reduces the greenhouse effect.

Carbon dioxide is the most famous of greenhouse gases. Natural sources of CO2 are volcanic emissions, the vital activity of organisms. Anthropogenic sources are the burning of fossil fuels (including forest fires), as well as a number of industrial processes (for example, the production of cement, glass). Carbon dioxide, according to most researchers, is primarily responsible for global warming caused by the "greenhouse effect". The CO 2 concentration over two centuries of industrialization has increased by more than 30% and is correlated with a change in global average temperature.

Methane is the second most important greenhouse gas. It is released due to leaks in the development of coal and natural gas deposits, from pipelines, during biomass burning, in landfills (as an integral part of biogas), as well as in agriculture (cattle breeding, rice growing), etc. Livestock, fertilizer use, coal burning and other sources produce about 250 million tons of methane per year. The amount of methane in the atmosphere is small, but its greenhouse effect or global warming potential (GWP) is 21 times stronger than that of CO 2.

Nitrous oxide is the third most important greenhouse gas: its effect is 310 times stronger than that of CO 2, but it is contained in very small amounts in the atmosphere. It enters the atmosphere as a result of the vital activity of plants and animals, as well as during the production and use of mineral fertilizers and the work of chemical industry enterprises.

Halocarbons (hydrofluorocarbons and perfluorocarbons) are gases created to replace ozone-depleting substances. Used mainly in refrigeration equipment. They have extremely high coefficients of influence on the greenhouse effect: 140-11700 times higher than that of CO 2. Their emissions (emission into the environment) are small, but they increase rapidly.

Sulfur hexafluoride - its release into the atmosphere is associated with electronics and the production of insulating materials. While it is small, but the volume is constantly increasing. Global warming potential is 23900 units.

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Changing of the climate   - fluctuations in the climate of the Earth as a whole or its individual regions over time. His study is engaged in the science of paleoclimatology. Climate change is caused by dynamic processes on Earth, external influences, such as fluctuations in the intensity of solar radiation, and, recently, human activity. Recently, the term “climate change” is usually used (especially in the context of environmental policy) to indicate changes in modern climate (see global warming).

Climate change factors

Climate change is caused by changes in the Earth’s atmosphere, processes occurring in other parts of the Earth, such as oceans and glaciers, as well as effects associated with human activities. External processes that form the climate are changes in solar radiation and the Earth's orbit.

• changing the size and relative position of continents and oceans,
• changing the luminosity of the sun
• changes in the parameters of the Earth's orbit,
• a change in the transparency of the atmosphere and its composition as a result of changes in the Earth’s volcanic activity,
• changing the concentration of greenhouse gases (CO 2 and CH 4) in the atmosphere,
• change in the reflectivity of the Earth's surface (albedo),
• change in the amount of heat available in the depths of the ocean.

Climate change on Earth

Weather is the daily state of the atmosphere. The weather is a chaotic non-linear dynamic system. Climate is the average state of the weather and, on the contrary, it is stable and predictable. Climate includes indicators such as average temperature, rainfall, sunny days and other variables that can be measured in a particular location. However, on Earth there are also such processes that can affect the climate.

Icing

There is skepticism about geo-engineering methods for removing carbon dioxide from the atmosphere, in particular, about proposals to dispose of carbon dioxide in tectonic cracks or pump it into rocks on the ocean floor: the removal of 50 ppm gas using this technology will cost at least $ 20 trillion which is twice the national debt of the United States.

Tectonics of lithospheric plates

Over long periods of time, tectonic plate movements move continents, form oceans, create and destroy mountain ranges, that is, create a surface on which a climate exists. Recent studies show that tectonic movements exacerbated 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 periods, changes in solar activity are also observed: the 11-year solar cycle and longer modulations. However, the 11-year cycle of the occurrence and disappearance of sunspots is not explicitly tracked in climatological data. Changes in solar activity are considered to be an important factor in the onset of the Little Ice Age, as well as some warming observed between 1900 and 1950. The cyclical nature of solar activity is not yet fully understood; it differs from the slow changes that accompany the development and aging of the sun.

Orbit changes

In terms of their effect on climate, changes in the Earth's orbit are similar to variations in solar activity, since small deviations in the position of the orbit lead to a redistribution of solar radiation on the Earth's surface. Such changes in the position of the orbit are called Milankovitch cycles, they are predictable with high accuracy, because they are the result of the physical interaction of the Earth, its moon satellite and other planets. Changes in the orbit are considered to be the main reasons for the alternation of glacial and interglacial cycles of the last ice age. The precession of the Earth’s orbit also results in smaller-scale changes, such as the periodic increase and decrease in the Sahara desert area.

Volcanism

One strong volcanic eruption can affect the climate, causing a cooling of several years. For example, the eruption of the Pinatubo volcano in 1991 significantly affected the climate. Giant eruptions that form the largest igneous provinces occur only a few times in a hundred million years, but they affect the climate for millions of years and cause extinction of species. At the beginning, scientists believed that the cause of the cooling is emitted into the atmosphere of volcanic dust, because it prevents solar radiation from reaching the Earth’s surface. However, measurements show that most of the dust accumulates on the surface of the Earth within six months.

Volcanoes are also part of the geochemical carbon cycle. Over many geological periods, carbon dioxide was released from the Earth’s interior into the atmosphere, thereby neutralizing the amount of CO 2 removed from the atmosphere and bound by sedimentary rocks and other geological sinks of CO 2. However, this contribution cannot be compared in magnitude with anthropogenic emission of carbon monoxide, which, according to estimates of the US Geological Survey, is 130 times higher than the amount of CO 2 emitted by volcanoes.

Anthropogenic impact on climate change

Human factors include human activity that changes the environment and affects climate. In some cases, the causal relationship is direct and unambiguous, as, for example, with the effect of irrigation on temperature and humidity, in other cases this relationship is less obvious. Various hypotheses of human influence on climate have been discussed for many years. At the end of the 19th century, for example, the theory of "rain comes to plow" (eng. Rain follows the plow) was popular in the western part of the United States and Australia.

The main problems today are the growing concentration of CO2 in the atmosphere due to fuel combustion, aerosols in the atmosphere affecting its cooling, and the cement industry. Other factors, such as land use, ozone depletion, animal husbandry and deforestation, also affect climate.

Burning fuel

Starting to grow during the industrial revolution in the 1850s and gradually accelerating, human consumption of fuel led to an increase in the concentration of CO 2 in the atmosphere from ~ 280 ppm to 380 ppm. With such growth, the projected concentration at the end of the 21st century will be more than 560 ppm. It is known that now the level of CO 2 in the atmosphere is higher than ever in the last 750,000 years. Together with the increasing methane concentration, these changes foretell a temperature rise of 1.4–5.6 ° C between 1990 and 2100.

Aerosols

It is believed that anthropogenic aerosols, especially sulphates emitted during fuel combustion, affect the cooling of the atmosphere. It is believed that this property is the cause of the relative "plateau" on the temperature graph in the middle of the XX century.

Cement industry

Cement production is an intense source of CO 2 emissions. Carbon dioxide is formed when calcium carbonate (CaCO 3) is heated to obtain the cement ingredient calcium oxide (CaO or quicklime). Cement production accounts for about 2.5% of CO 2 emissions from industrial processes (energy and industrial sectors). When cement is mixed, the same amount of CO 2 is absorbed from the atmosphere when the CaO + CO 2 = CaCO 3 reaction takes place. Therefore, production and consumption of cement only changes local concentrations of CO 2 in the atmosphere without changing the average value.

Land use

Land use has a significant impact on climate. Irrigation, deforestation and agriculture are fundamentally changing the environment. For example, the water balance changes in the irrigated area. Land use can change the albedo of a single territory, as it changes the properties of the underlying surface and thus the amount of absorbed solar radiation. For example, there are reasons to assume that the climate of Greece and other Mediterranean countries has changed due to large-scale deforestation between 700 BC. er and the beginning of n. er (wood was used for construction, shipbuilding and as fuel), becoming more hot and dry, and those types of trees that were used in shipbuilding do not grow more in this area.

According to a 2007 study of the Jet Propulsion Laboratory, the average temperature in California has increased by 2 ° C over the past 50 years, and this increase is much higher in cities. This is mainly due to anthropogenic changes in the landscape.

Herding

According to a 2006 UN report, “The Long Shadow of Livestock”, livestock is responsible for 18% of global greenhouse gas emissions. This includes changes in land use, that is, deforestation for pastures. In the Amazon rainforest, 70% of deforestation is done for pastures, which was the main reason why the Food and Agriculture Organization of the United Nations (FAO) in its 2006 agricultural report included land use in the sphere of cattle breeding. In addition to CO2 emissions, cattle breeding is responsible for emissions of 65% nitric oxide and 37% methane, which are of anthropogenic origin.

Interaction of factors

The impact on the climate of all factors, both natural and man-made, is expressed by a single value - the radiation heating of the atmosphere in W / m 2.

Volcanic eruptions, glaciation, continental drift and the displacement of the Earth’s poles are powerful natural processes that affect the Earth’s climate. On a scale of several years, volcanoes can play a major role. As a result of the eruption of the volcano Penatubo in 1991 in the Philippines, so much ash was thrown to an altitude 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 relatively quickly settle down. Over the millennia, the climate-determining process will probably be a slow movement from one glacial period to the next.

On a scale of several centuries for 2005 compared with 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 heating by 2.4–3.0 W / m 2. Human influence is less than 1% of the total radiation balance, and the anthropogenic enhancement of the natural greenhouse effect is about 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 (from about 1750) 0.7 ° C (