Greenhouse effect: causes and solutions. Greenhouse effect: essence and characteristics

The problem of the greenhouse effect is especially relevant in our century, when we are destroying forests to build another industrial plant, and many of us cannot imagine life without a car. We, like ostriches, bury our heads in the sand, not noticing the harm from our activities. Meanwhile, the greenhouse effect is intensifying and leading to global disasters.

The phenomenon of the greenhouse effect has existed since the appearance of the atmosphere, although it was not so noticeable. Nevertheless, its study began long before the active use of cars and.

Brief Definition

The greenhouse effect is an increase in the temperature of the planet's lower atmosphere due to the accumulation of greenhouse gases. Its mechanism is as follows: the sun's rays penetrate the atmosphere and heat the surface of the planet.

Thermal radiation that comes from the surface should return to space, but the lower atmosphere is too dense for them to penetrate. The reason for this is greenhouse gases. Heat rays linger in the atmosphere, increasing its temperature.

History of greenhouse effect research

People first started talking about the phenomenon in 1827. Then an article by Jean Baptiste Joseph Fourier appeared, “A Note on Temperatures.” globe and other planets”, where he outlined in detail his ideas about the mechanism of the greenhouse effect and the reasons for its appearance on Earth. In his research, Fourier relied not only on his own experiments, but also on the judgments of M. De Saussure. The latter conducted experiments with a glass vessel blackened from the inside, closed and placed in sunlight. The temperature inside the vessel was much higher than outside. This is explained by the following factor: thermal radiation cannot pass through the darkened glass, which means it remains inside the container. At the same time, sunlight easily penetrates through the walls, since the outside of the vessel remains transparent.

Several formulas

Total energy solar radiation absorbed per unit time by a planet with radius R and spherical albedo A is equal to:

E = πR2 ( E_0 over R2) (1 – A),

where E_0 is the solar constant, and r is the distance to the Sun.

In accordance with the Stefan-Boltzmann law, the equilibrium thermal radiation L of a planet with radius R, that is, the area of the emitting surface is 4πR2:

L=4πR2 σTE^4,

where TE is the effective temperature of the planet.

Causes

The nature of the phenomenon is explained by the different transparency of the atmosphere for radiation from space and from the surface of the planet. For sun rays The planet's atmosphere is transparent, like glass, and therefore they pass through it easily. And for thermal radiation, the lower layers of the atmosphere are “impenetrable”, too dense for passage. That is why part of the thermal radiation remains in the atmosphere, gradually descending to its lowest layers. At the same time, the amount of greenhouse gases thickening the atmosphere is growing.

Back in school we were taught that the main cause of the greenhouse effect is human activity. Evolution has led us to industry, we burn tons of coal, oil and gas, producing fuel. The consequence of this is the release of greenhouse gases and substances into the atmosphere. Among them are water vapor, methane, carbon dioxide, Nitric oxide. It’s clear why they are named like that. The surface of the planet is heated by the sun's rays, but it necessarily “gives” some of the heat back. Thermal radiation that comes from the Earth's surface is called infrared.

Greenhouse gases in the lower part of the atmosphere prevent heat rays from returning to space and trap them. As a result, the average temperature of the planet is increasing, and this leads to dangerous consequences.

Is there really nothing that can regulate the amount of greenhouse gases in the atmosphere? Of course it can. Oxygen does this job perfectly. But the problem is that the planet’s population is growing inexorably, which means that more and more oxygen is being consumed. Our only salvation is vegetation, especially forests. They absorb excess carbon dioxide and release much large quantity oxygen than people consume.

Greenhouse effect and Earth's climate

When we talk about the consequences of the greenhouse effect, we understand its impact on the Earth's climate. First of all, this is global warming. Many people equate the concepts of “greenhouse effect” and “global warming”, but they are not equal, but interrelated: the first is the cause of the second.

Global warming is directly related to the oceans. Here is an example of two cause-and-effect relationships.

The average temperature of the planet is rising, liquid begins to evaporate. This also applies to the World Ocean: some scientists are afraid that in a couple of hundred years it will begin to “dry up.”
At the same time, due to high temperatures, glaciers and sea ice will begin to actively melt in the near future. This will lead to an inevitable rise in sea levels.

We are already observing regular floods in coastal areas, but if the level of the World Ocean rises significantly, all nearby land areas will be flooded and crops will perish.

Impact on people's lives

Do not forget that an increase in the average temperature of the Earth will affect our lives. The consequences can be very serious. Many areas of our planet, already prone to drought, will become absolutely unviable, people will begin to migrate en masse to other regions. This will inevitably lead to socio-economic problems and the outbreak of the third and fourth world wars. Lack of food, destruction of crops - this is what awaits us in the next century.

But does it have to wait? Or is it still possible to change something? Can humanity reduce the harm from the greenhouse effect?

Actions that can save the Earth

Today, all the harmful factors that lead to the accumulation of greenhouse gases are known, and we know what needs to be done to stop it. Don't think that one person won't change anything. Of course, only all of humanity can achieve the effect, but who knows - maybe a hundred more people are reading a similar article at this moment?

Forest conservation

Stopping deforestation. Plants are our salvation! In addition, it is necessary not only to preserve existing forests, but also to actively plant new ones.

Every person should understand this problem.

Photosynthesis is so powerful that it can provide us with huge amounts of oxygen. It will be enough for the normal life of people and the elimination of harmful gases from the atmosphere.

Use of electric vehicles

Refusal to use fuel-powered vehicles. Every car emits a huge amount of greenhouse gases per year, so why not make healthier choices environment? Scientists are already offering us electric cars - environmentally friendly cars that do not use fuel. The minus of a “fuel” car is another step towards eliminating greenhouse gases. All over the world they are trying to speed up this transition, but so far the modern developments of such machines are far from perfect. Even in Japan, where such cars are used the most, they are not ready to completely switch to their use.

Alternative to hydrocarbon fuels

Invention alternative energy. Humanity doesn't stand still, so why are we stuck using coal, oil and gas? Burning these natural components leads to the accumulation of greenhouse gases in the atmosphere, so it's time to go green clean look energy.

We cannot completely abandon everything that emits harmful gases. But we can help increase oxygen in the atmosphere. Not only a real man Every person must plant a tree!

What is the most important thing in solving any problem? Don't close your eyes to her. We may not notice the harm from the greenhouse effect, but future generations will definitely notice it. We can stop burning coal and oil, preserve the natural vegetation of the planet, abandon a conventional car in favor of an environmentally friendly one - and all for what? So that our Earth will exist after us.

The greenhouse effect is a rise in temperature on the surface of the planet as a result of thermal energy that appears in the atmosphere due to heating of gases. The main gases that lead to the greenhouse effect on Earth are water vapor and carbon dioxide.

The greenhouse effect allows us to maintain a temperature on the surface of the Earth at which the emergence and development of life is possible. If there were no greenhouse effect, the average surface temperature of the globe would be much lower than it is now. However, as the concentration of greenhouse gases increases, the impermeability of the atmosphere to infrared rays increases, which leads to an increase in the Earth's temperature.

In 2007, the Intergovernmental Panel on Climate Change (IPCC), the most authoritative international body that brings together thousands of scientists from 130 countries, presented its Fourth Assessment Report, which contained generalized conclusions about past and present climate changes, their impact on nature and people , as well as possible measures to counter such changes.

According to published data, between 1906 and 2005 the average temperature of the Earth rose by 0.74 degrees. In the next 20 years, the temperature increase, according to experts, will average 0.2 degrees per decade, and by the end of the 21st century, the Earth's temperature may increase from 1.8 to 4.6 degrees (this difference in data is the result of the superposition of a whole complex of models future climate, which took into account various scenarios for the development of the world economy and society).

According to scientists, with a 90 percent probability, the observed climate changes are associated with human activity - the burning of carbon-based fossil fuels (i.e. oil, gas, coal, etc.), industrial processes, as well as the clearing of forests - natural absorbers of carbon dioxide from the atmosphere .

Possible consequences of climate change:
1. Changes in the frequency and intensity of precipitation.
In general, the planet's climate will become wetter. But the amount of precipitation will not spread evenly across the Earth. In regions that already receive sufficient precipitation today, their precipitation will become more intense. And in regions with insufficient moisture, dry periods will become more frequent.

2. Sea level rise.
During the 20th century, the average sea level increased by 0.1-0.2 m. According to scientists, during 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. Countries such as the Netherlands, Great Britain, and the small island states of Oceania and the Caribbean will be the first to be at risk of flooding. In addition, high tides will become more frequent and coastal erosion will increase.

3. Threat to ecosystems and biodiversity.
There are predictions that up to 30-40% of plant and animal species will disappear because their habitats will change faster than they can adapt to these changes.

When the temperature rises by 1 degree, a change in species composition forests. Forests are a natural store of carbon (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 large amounts of carbon.

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

According to scientists, the thickness of the Himalayan ice is melting 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 completely melt.
Accelerating glacier melt poses a number of immediate threats to human development. For densely populated mountain and foothill areas, avalanches, flooding or, conversely, a decrease in the full flow of rivers, and as a consequence a decrease in reserves, pose a particular danger fresh water.

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

The biggest blow could be to the poorest countries, those least prepared to adapt to climate change. According to the IPCC, the number of people facing hunger could increase by 600 million by 2080, double the number of people currently living in poverty in sub-Saharan Africa.

6. Water consumption and water supply.
One of the consequences of climate change may be a shortage drinking water. In regions with arid climates ( central Asia, Mediterranean, South Africa, Australia, etc.) the situation will worsen due to a decrease in precipitation levels.
Due to the melting of glaciers, the flow of the largest waterways of Asia - the Brahmaputra, Ganges, Yellow River, Indus, Mekong, Saluan and Yangtze - will significantly decrease. A lack of fresh water will not only affect 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 the less affluent segments of the population. So, production reduction food will inevitably lead to malnutrition and hunger. Abnormally high temperatures can lead to exacerbation of cardiovascular, respiratory and other diseases.

Rising temperatures may lead to changes in geographic distribution various types who are carriers of diseases. As temperatures rise, the ranges of heat-loving animals and insects (e.g. encephalitis ticks 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 completely prevent the predicted climate changes. However, it is humanly possible to mitigate climate change, to curb the rate of temperature rise in order to avoid dangerous and irreversible consequences in the future. First of all, due to:
1. Restrictions and reductions in the consumption of fossil carbon fuels (coal, oil, gas);
2. Increasing the efficiency of energy consumption;
3. Introduction of energy saving measures;
4. Increased use of non-carbon and renewable energy sources;
5. Development of new environmentally friendly and low-carbon technologies;
6. Through the prevention of forest fires and forest restoration, since forests are natural absorbers of carbon dioxide from the atmosphere.

The greenhouse effect does not only occur on Earth. Strong greenhouse effect - on the neighboring planet, Venus. The atmosphere of Venus consists almost entirely of carbon dioxide, and as a result the planet's surface is heated to 475 degrees. Climatologists believe that the Earth avoided such a fate thanks to the presence of oceans. The oceans absorb atmospheric carbon and it accumulates in rocks, such as limestone - through this, carbon dioxide is removed from the atmosphere. There are no oceans on Venus, and all the carbon dioxide that volcanoes emit into the atmosphere remains there. As a result, the planet experiences an uncontrollable greenhouse effect.

The material was prepared based on information from RIA Novosti and open sources

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The essence of the greenhouse effect.

The air we breathe is a necessary condition our lives in many aspects. Without our atmosphere, the average temperature on Earth would be about -18 0 C instead of today's 15 0 C. All the sunlight entering the Earth (about 180 W/m2) causes the Earth to emit infrared waves like a giant radiator. The reflected heat would simply return unhindered to space.

Because of the atmosphere, however, only some of this heat is directly returned to space. The remainder is retained in the lower layers of the atmosphere, which contain a number of gases - water vapor, CO 2, methane and others - that collect outgoing infrared radiation. As soon as these gases heat up, some of the heat they accumulated is released back to the earth's surface. In general, this process is called the greenhouse effect, the main reason for which is the excess content of greenhouse gases in the atmosphere. The more greenhouse gases in the atmosphere, the more heat reflected by the earth's surface will be retained. Since greenhouse gases do not prevent the flow of solar energy, the temperature at the earth's surface will increase.

As temperatures rise, the evaporation of water from oceans, lakes, rivers, etc. will increase. Since heated air can contain more water vapor, this creates powerful effect feedback: the warmer it gets, the higher the content of water vapor in the air, and this, in turn, increases the greenhouse effect. Human activity has little effect on the amount of water vapor in the atmosphere. But we emit other greenhouse gases, which makes the greenhouse effect more and more intense. Scientists believe that increasing CO 2 emissions, mostly from burning fossil fuels, explain at least about 60% of the Earth's warming since 1850. The concentration of carbon dioxide in the atmosphere is increasing by about 0.3% per year, and is now about 30% higher than before the industrial revolution. If we express this in absolute terms, then every year humanity adds approximately 7 billion tons. Despite the fact that this is a small part in relation to the total amount of carbon dioxide in the atmosphere - 750 billion tons, and even smaller compared to the amount of CO 2 contained in the World Ocean - approximately 35 trillion tons, it remains very significant. Reason: natural processes are in equilibrium, such a volume of CO 2 enters the atmosphere, which is removed from there. And human activity only adds CO 2.

If current rates continue, atmospheric carbon dioxide levels will double pre-industrial levels by 2060 and quadruple by the end of the century. This is very concerning because the life cycle of CO 2 in the atmosphere is more than a hundred years, compared to the eight-day cycle of water vapor. Posted on http://www.allbest.ru/

Methane, main component natural gas, is responsible for 15% of global warming modern times. Generated by bacteria in rice fields, decaying garbage, agricultural products and fossil fuels, methane has been circulating in the atmosphere for about a decade. Now there is 2.5 times more of it in the atmosphere than in the 18th century.

Another greenhouse gas is nitrous oxide, produced as agriculture, and by industry - various solvents and refrigerants, such as chlorofluorocarbons (freons), which are prohibited by international agreement due to their destructive effect on the protective ozone layer of the Earth. The unrelenting accumulation of greenhouse gases in the atmosphere has led scientists to decide that in this century the average temperature will increase from 1 to 3.5 0 C. (see Appendix No. 1) For many, this may not seem like much. Let's give an example to explain. The abnormal cooling in Europe, which lasted from 1570 to 1730, forcing European farmers to abandon their fields, was caused by a temperature change of only half a degree Celsius. You can imagine what consequences a temperature increase of 3.5 0 C could have.

Ways to study climate change.

In modern times, the invention of various computer models of climate change on Earth is becoming popular. They are based on the interaction of various climatic factors, such as soil, air, water, glaciers and solar energy. These general circulation models consist of equations showing the learned relationships between atmospheric physics and ocean circulation.

For each part of the planet, scientists calculated the effect of factors such as temperature, the rotation of the Earth, the part of the surface above sea level and other climatic conditions.

But how plausible are these projects? A model is considered perfect if, when entering information about climatic conditions on Earth several hundred years ago, it gives an accurate description of today's climate. It is very rare that today's models produce a result comparable to the real global climate without various inaccuracies.

This is partly due to the fact that only the most powerful computers can cope with this task. And partly because some aspects of climate change are not fully understood. The modelers caution that their creations are not yet advanced enough to determine the detailed effect in specific regions. The models divide the entire surface of the Earth into squares, usually 200 km on a side, but factors such as ocean storms, storms and cloud activity affect much smaller areas. In these cases, models can determine an approximate outcome. Computer models routinely project the greenhouse effect into the distant future, and they are getting better and better at adapting to humanity's rapidly growing body of knowledge. In addition, it is incredibly difficult to correctly account for human influence on global climate fluctuations.

According to Kevin Trenberth, a leading US scientist at the National Center for Atmospheric Research in Colorado, all computer models predict global warming, but they can only determine the limits of temperature change. The warming could be one degree Celsius this century, or it could be more than three times as much. "The use of such models is an important and indispensable tool," says Trenberth, "but they cannot solve the problem of the greenhouse effect."

The influence of carbon dioxide on the intensity of the greenhouse effect.

Much still needs to be learned about the carbon cycle and the role of the world's oceans as a vast reservoir of carbon dioxide. As mentioned above, every year humanity adds 7 billion tons of carbon in the form of CO 2 to the existing 750 billion tons. But only about half of our emissions - 3 billion tons - remain in the air. This can be explained by the fact that most of the CO 2 is used by terrestrial and marine plants, is buried in marine sedimentary rocks, and is absorbed sea water or otherwise absorbed. Of this large portion of CO 2 (about 4 billion tons), the ocean absorbs about two billion tons of atmospheric carbon dioxide each year. All this increases the number of unanswered questions: How exactly does seawater interact with atmospheric air, absorbing CO 2? How much more carbon can the seas absorb, and at what level? global warming can affect their capacity? What is the capacity of the oceans to absorb and store heat trapped by climate change?

The role of clouds and suspended particles in air currents, called aerosols, are not easy to take into account when building a climate model. Clouds shade the earth's surface, leading to cooling, but depending on their height, density and other conditions, they can also trap heat reflected from the earth's surface, increasing the intensity of the greenhouse effect. The effect of aerosols is also interesting. Some of them modify water vapor, condensing it into small droplets that form clouds. These clouds are very dense and obscure the Earth's surface for weeks. That is, they block sunlight until they fall with precipitation. The combined effect can be enormous: the 1991 eruption of Mount Pinatuba in the Philippines released a colossal volume of sulfates into the stratosphere, causing a worldwide drop in temperature that lasted two years.

Thus, our own pollution, mainly caused by burning sulfur-containing coal and oils, may temporarily offset the effects of global warming. Experts estimate that aerosols reduced the amount of warming by 20% during the 20th century. In general, temperatures have been rising since the 1940s, but have fallen since 1970. The aerosol effect may help explain the anomalous cooling in the middle of the last century.

In 1996, carbon dioxide emissions into the atmosphere amounted to 24 billion tons. A very active group of researchers argues against the idea that human activity is one of the causes of global warming. In her opinion, the main thing is the natural processes of climate change and increased solar activity. But, according to Klaus Hasselmann, head of the German Climatological Center in Hamburg, only 5% can be explained by natural causes, and the remaining 95% is a man-made factor caused by human activity. Some scientists also do not connect the increase in CO 2 with an increase in temperature. Skeptics say that if rising temperatures are to be blamed on rising CO 2 emissions, temperatures must have risen during the post-war economic boom, when fossil fuels were burned in huge quantities. However, Jerry Mallman, director of the Geophysical Fluid Dynamics Laboratory, calculated that increased use of coal and oils rapidly increased the sulfur content in the atmosphere, causing cooling. After 1970, the thermal effect of the long life cycles of CO 2 and methane suppressed rapidly decaying aerosols, causing temperatures to rise. Thus, we can conclude that the influence of carbon dioxide on the intensity of the greenhouse effect is enormous and undeniable.

However, the increasing greenhouse effect may not be catastrophic. Indeed, high temperatures may be welcome where they are quite rare. Since 1900, the greatest warming has been from 40 to 70 0 northern latitude, including Russia, Europe, and the northern part of the United States, where industrial emissions of greenhouse gases began first. Most of warming occurs at night, primarily due to increased cloud cover, which traps outgoing heat. As a result, the sowing season was extended by a week.

Moreover, the greenhouse effect may be good news for some farmers. High concentrations of CO 2 can have a positive effect on plants because plants use carbon dioxide during photosynthesis, converting it into living tissue. Therefore, more plants mean more absorption of CO 2 from the atmosphere, slowing down global warming.

This phenomenon was studied by American specialists. They decided to create a model of the world with double the amount of CO 2 in the air. To do this, they used fourteen-year-old pine forest in Northern California. Gas was pumped through pipes installed among the trees. Photosynthesis increased by 50-60%. But the effect soon became the opposite. The suffocating trees could not cope with such volumes of carbon dioxide. The advantage in the process of photosynthesis was lost. This is another example of how human manipulation leads to unexpected results.

But these are small positive aspects the greenhouse effect cannot be compared with the negative ones. Take, for example, the experience with a pine forest, where the volume of CO 2 was doubled, and by the end of this century the concentration of CO 2 is predicted to quadruple. One can imagine how catastrophic the consequences could be for plants. And this, in turn, will increase the volume of CO 2, since what fewer plants, the greater the concentration of CO 2. greenhouse effect research

Global warming.

The significance of warming, determined by American scientists, could trigger a widespread catastrophe. First, warming will cause an increase in the concentration of water vapor in the atmosphere (6% more for each degree of temperature increase), which will cause an increase in precipitation and possibly more intense weather in general.

While the frequency of rain and snowfall may increase, the most expected effect is that average precipitation fluctuations may become even more pronounced, according to Thomas Karl, an American climate change expert. In areas prone to flooding and water erosion, the forecast will be dire. The increase in precipitation will be extremely uneven, flooding the most humid areas and making dry areas even drier.

In addition, Karl suggests that heat waves could become even more severe in areas where the area has little chance of cooling at night. A three-degree increase in average temperature will increase the possibility of dangerous heat waves (above 35 0 C) occurring in mid-latitudes from once every 12 years to once every 4 years.

Such cruel pictures are becoming more and more believable. There is unanimous agreement that global average temperatures have risen by half a degree Celsius since the late 18th century, with 13 of the hottest years occurring since 1980. By some estimates, 1997 was the hottest. This is indisputable evidence that humanity is involved in global warming.

The warming may also be part of a natural cycle of fluctuations in average temperatures, which have fluctuated by up to 6 degrees Celsius over the past 150,000 years. Climatic fluctuations over millennia depend on periodic changes in solar activity, the orbit and tilt of the Earth, that is, the amount of heat entering the Earth.

The Earth's rotation does not maintain a constant position relative to the Sun. In the 1930s, Serbian mathematician Milutin Milanković established that there is a relationship between three main cycles of the Earth's motion and its climate: the 100,000-year cycle of the Earth's orbit, the 41,000-year cycle of the Earth's axis tilt, and the 23,000-year cycle of the Earth's axis wobble.

The effect of these cycles can be seen in the graph of ice volume relative to sunlight, which increased as solar intensity fell, allowing snowpack to extend its melting period and accumulate over time.

According to these cycles, we are now in the middle of a cooling period. And currently there is an increase in temperature, as if we are in a warming period.

Evidence of these climate changes was drawn from the composition of ice mined from the depths of ancient glaciers in Greenland and Antarctica and from the remains of marine organisms in sedimentary rocks on the seafloor.

The rise and fall in temperature over the past 750,000 years was also examined by analyzing an ancient Tibetan 300-metre glacier - the largest in the mid-latitudes. Ice samples were collected from various depths. The content of a special oxygen isotope, 18 O, was measured in each sample. The higher its content, the higher the temperature in the corresponding period.

Based on this research, a graph was created. The resulting temperature was superimposed on a graph of solar intensity variations according to the 100,000-year Milankovitch cycle.

It is possible that around 1860, when scientists first took up the problem of global warming, the planet was still in a period of abnormal cooling. The actual warming may be caused by the end of this period, and the greenhouse effect may be superimposed on this direction of climate fluctuation.

However, in refutation of this opinion, for many scientists the critical aspect is the rate of today's climate warming, which cannot be compared with the rates of natural climate fluctuations. In the 20th century, warming amounted to 0.5 0 C, it was unusually large, sudden and widespread.

Over the past 150 years, a decrease in ice cover due to global warming has been observed throughout the planet. And over the past 40 years, the temperature in Antarctica has increased by 2.5 0 C, one of the largest ice fields has decreased by one third, and another has melted by 1300 m 2 in 1995 alone. Melting glaciers have already led to a rise in sea levels by 10-25 cm in the last century. It is known that if the level of the World Ocean rises by 1 meter, many coastal cities will be flooded.

The decrease in ice cover can be seen using the example of a glacier in Switzerland, which 150 years ago was part of the Alps. “If the climate continues to change at these incredible rates, as we believe it will, the magnitude of the future greenhouse effect will be enormous, even on a geological scale,” says Thomas Roofley, an American oceanographer.

Consequences of the greenhouse effect.

What is the urgency of action considered at the 1997 climate change conference in Kyoto, Japan, at which industrial nations agreed in principle to reduce greenhouse gas emissions? No other issue is as hotly contested among scientists and politicians as this one. Some say immediate action is not warranted: tangible climate changes, they say, are gradual enough for us to adapt to. And even if all emissions of greenhouse gases into the atmosphere stopped tomorrow, the planet would still warm for several decades due to the long life cycle of gases in the atmosphere.

On the other hand, there is evidence that some events can radically change the climate over a period of several tens of days. Perhaps the biggest fear is the sudden collapse of the vast Atlantic Transport Belt, a system that brings warm water north of the equator, making Europe several degrees warmer. The evaporation of this influx leaves this belt with a greater concentration of salt than the remaining North Atlantic, which contains a persistent excess of water from the continental basins. The belt becomes colder and denser as it reaches Greenland, where it completely sinks.

But what if human-induced global warming changes the temperature difference between the currents and, at the same time, increases precipitation, diluting the salinity of the northward flow? The entire Atlantic transport belt could shut down, as evidenced by oceanic sediments, as it has done several times in the past. The effect will be disastrous. According to some calculations, Ireland will have the same temperature as today in Svalbard, which is located hundreds of kilometers above the Arctic Circle. Almost all of northern Europe will be uninhabitable.

But no one knows for sure whether such things will happen. In addition, the specific human effect on climate change will remain for a long time uncertain until our knowledge increases and models improve. "The next ten years will tell," says Tim Barnett, a climate scientist at the Institute of Oceanography in California. "We'll have to wait until then to really see."

Factors of climate change.

After assessing the opinions of various experts, it can be determined that the climate is changing due to various combinations of various climatic factors, the mechanism of many of which is not yet understood modern science. Here is a list of the main climatic factors.

Solar radiation. Having flown 149 billion kilometers, sunlight heats upper layer atmosphere with an intensity of 180 W/m2. One third of this heat is reflected back into space. The remainder passes through the atmosphere, warming the earth's surface.

Atmosphere. The delicate balance of gases in the atmosphere gives the Earth an average temperature of 15 0 C. Greenhouse gases - water vapor, CO 2, methane, nitrogen oxides and others - trap the energy reflected by the earth's surface and reflect it back to the earth.

Oceans. Covering 71% of the earth's surface area, the oceans are the main source of atmospheric water vapor. Oceans can retain heat for a long time and transport it thousands of kilometers. When warm water collects in one area, evaporation and cloud formation can increase. Marine organisms consume huge amounts of carbon dioxide.

The water cycle. Rising air temperatures can mean increased water evaporation and melting of ice on water and land. Water vapor is also the most efficient and effective greenhouse gas. However, cloud formation can have a cooling effect.

Clouds. The role of clouds is not fully understood, but it is known that clouds have a dual effect: they cool, shading the earth's surface, and heat, trapping heat reflected by the earth's surface.

Glaciers and snow covers. Bright White color Glaciers and snow caps reflect sunlight back into space, cooling the planet. Melting ice in the oceans lowers water temperatures. In the Northern Hemisphere, the area of snow cover has decreased by 10% over the past 25 years, but a significant decrease in ice volume has not yet been observed in Antarctica. Although the likelihood of this happening is constantly increasing.

Earth's surface. When solar energy hits the earth's surface, it turns into heat, some of which is quickly reflected into the atmosphere. Therefore the topography ( mutual arrangement individual localities 1) and land cultivation have a huge impact on the climate. Mountain ranges can block the movement of clouds, creating dry areas in the direction of the wind. Loose soils can absorb more moisture, making the air drier. A rainforest can absorb large amounts of carbon dioxide, but if the forest is cut down, that same area will become a source of methane. If such a forest is burned, it will be released a large number of carbon dioxide. On average, across the planet, forest burning accounts for half of the increase in CO 2 in the atmosphere.

Human impact. By adding greenhouse gases to the atmosphere, humanity causes global warming. Burning fuel is main reason increasing CO 2 concentration. Cattle farming, rice cultivation and landfills have increased methane levels in the atmosphere. Aerosols and industrial sulfate emissions reflect incoming sunlight, producing a temporary, localized cooling effect.

In 1992, in Rio de Janeiro, the leading industrial countries committed themselves to reducing carbon dioxide emissions to 1990 levels by the year 2000. Upon taking office in 1993, US President Bill Clinton emphasized the importance of achieving the goals set in Rio de Janeiro. But at the end of October 1999, he said that only by 2008 could industrialized countries return to the level of greenhouse gas emissions in 1990, and only if China also committed to adopting relevant laws in its country.

Now, on average, a US resident burns so much fuel annually that 19 tons of carbon dioxide are released (in Germany - 11 tons, in China - two, in India - one ton).

Greenhouse gases.

Greenhouse gases are gases that are believed to cause the global greenhouse effect.

The main greenhouse gases, in order of their estimated impact on the Earth's thermal balance, are water vapor, carbon dioxide, methane, ozone, halocarbons and nitrous oxide.

water vapor

Water vapor is the main natural greenhouse gas, responsible for more than 60% of the effect. Direct anthropogenic impact on this source is insignificant. At the same time, an increase in the Earth's temperature caused by other factors increases evaporation and the total concentration of water vapor in the atmosphere at an almost constant relative humidity, which, in turn, increases the greenhouse effect. Thus, there is some positive Feedback. On the other hand, clouds in the atmosphere reflect direct sunlight, thereby increasing the Earth's albedo, which reduces the effect somewhat.

Carbon dioxide

Sources of carbon dioxide in the Earth's atmosphere are volcanic emissions, vital activity of organisms, and human activity. Anthropogenic sources are the burning of fossil fuels, the burning of biomass (including deforestation), some industrial processes(for example, cement production). The main consumers of carbon dioxide are plants. Normally, the biocenosis absorbs approximately the same amount of carbon dioxide as it produces (including through biomass decay).

The main anthropogenic sources of methane are digestive fermentation in livestock, rice growing, and biomass burning (including deforestation). Recent studies have shown that a rapid increase in atmospheric methane concentrations occurred in the first millennium AD (presumably as a result of the expansion of agricultural and livestock production and forest burning). Between 1000 and 1700, methane concentrations fell by 40%, but began to rise again in recent centuries (presumably as a result of the expansion of arable land and pastures and forest burning, the use of wood for heating, increased numbers of livestock, sewage, and rice cultivation) . Some contribution to the supply of methane comes from leaks during the development of coal and natural gas deposits, as well as the emission of methane as part of biogas generated at waste disposal sites. Posted on Allbest.ru

Without the greenhouse effect, life on our planet would be in doubt

We can start with the fact that the greenhouse effect has existed on our planet throughout its history. This phenomenon is simply inevitable for those celestial bodies, which, like the Earth, have a stable atmosphere. Without it, for example, the World Ocean would have frozen long ago, and higher forms of life would not have appeared at all. Scientists have long scientifically proven that if there were no carbon dioxide in our atmosphere, the presence of which is a necessary component of the process of the greenhouse effect, then the temperature on the planet would fluctuate within -20 0 C, so there would be no talk of the emergence of life at all.

Causes and essence of the greenhouse effect

Answering the question: “What is the greenhouse effect?”, first of all, it should be noted that this physical phenomenon received its name by analogy with the processes that occur in gardeners’ greenhouses. Inside it, regardless of the time of year, it is always several degrees warmer than in the surrounding space. The thing is that plants absorb visible sunlight, which pass absolutely freely through glass, polyethylene, and in general through almost any obstacle. After this, the plants themselves also begin to emit energy, but in the infrared range, the rays of which can no longer freely overcome the same glass, so a greenhouse effect occurs. The reasons for this phenomenon, therefore, lie precisely in the imbalance between the spectrum of visible solar rays and those radiations that are emitted into external environment plants and other items.

The physical basis of the greenhouse effect

As for our planet as a whole, the greenhouse effect here arises due to the presence of a stable atmosphere. To maintain its temperature balance, the Earth must give off as much energy as it receives from the Sun. However, the presence of carbon dioxide and water in the atmosphere, which absorb infrared rays, thus performing the role of glass in a greenhouse, causes the formation of so-called greenhouse gases, some of which return back to the Earth. These gases create a "blanket effect", raising the temperature at the planet's surface.

Greenhouse effect on Venus

From the above we can conclude that the greenhouse effect is characteristic not only of the Earth, but also of all planets and other celestial bodies with a stable atmosphere. Indeed, research conducted by scientists has shown that, for example, near the surface of Venus this phenomenon is much more pronounced, which is due, first of all, to the fact that its air shell consists of almost one hundred percent carbon dioxide.

The greenhouse effect is an increase in the temperature of the earth's surface due to the heating of the lower layers of the atmosphere by the accumulation of greenhouse gases. As a result, the air temperature is higher than it should be, and this leads to irreversible consequences such as climate change and global warming. Several centuries ago this ecological problem existed, but was not so obvious. With the development of technology, the number of sources that provide the greenhouse effect in the atmosphere increases every year.

Causes of the greenhouse effect

the use of combustible minerals in industry - coal, oil, natural gas, the combustion of which releases huge amounts of carbon dioxide and other harmful compounds into the atmosphere;

transport – cars and trucks emit exhaust gases, which also pollute the air and increase the greenhouse effect;

deforestation, which absorbs carbon dioxide and releases oxygen, and with the destruction of every tree on the planet, the amount of CO2 in the air increases;

forest fires are another source of destruction of plants on the planet;

an increase in population affects the increase in demand for food, clothing, housing, and to ensure this, industrial production is growing, which increasingly pollutes the air with greenhouse gases;

agrochemicals and fertilizers contain varying amounts of compounds, the evaporation of which releases nitrogen, one of the greenhouse gases;

The decomposition and combustion of waste in landfills contributes to the increase in greenhouse gases.

The influence of the greenhouse effect on climate

Considering the results of the greenhouse effect, we can determine that the main one is climate change. As the air temperature increases every year, the waters of the seas and oceans evaporate more intensely. Some scientists predict that in 200 years the phenomenon of “drying” of the oceans, namely a significant decrease in water levels, will become noticeable. This is one side of the problem. The other is that rising temperatures lead to the melting of glaciers, which contributes to rising water levels in the World Ocean and leads to the flooding of the coasts of continents and islands. An increase in the number of floods and coastal inundation indicates that the level ocean waters is increasing every year.

An increase in air temperature leads to the fact that areas that are little moistened by precipitation become arid and unsuitable for life. Crops are destroyed here, which leads to a food crisis for the population of the area. Also, there is no food for the animals, since plants die out due to lack of water.

First of all, we need to stop deforestation and plant new trees and shrubs, as they absorb carbon dioxide and produce oxygen. By using electric vehicles, the amount of exhaust gases will be reduced. In addition, you can switch from cars to bicycles, which is more convenient, cheaper and better for the environment. Alternative fuels are also being developed, which, unfortunately, are slowly being introduced into our daily lives.

19. Ozone layer: significance, composition, possible causes of its destruction, protective measures taken.

Earth's ozone layer- this is the region of the Earth's atmosphere in which ozone is formed - a gas that protects our planet from the harmful effects of ultraviolet radiation.

Destruction and depletion of the Earth's ozone layer.

The ozone layer, despite its enormous importance for all living things, is a very fragile barrier to ultraviolet rays. Its integrity depends on a number of conditions, but nature nevertheless came to a balance in this matter, and for many millions of years the Earth’s ozone layer successfully coped with the mission entrusted to it. The processes of formation and destruction of the ozone layer were strictly balanced until man appeared on the planet and reached the current technical level in his development.

In the 70s twentieth century, it was proven that many substances actively used by humans in economic activities can significantly reduce ozone levels in Earth's atmosphere.

Substances that destroy the Earth's ozone layer include fluorochlorocarbons - freons (gases used in aerosols and refrigerators, consisting of chlorine, fluorine and carbon atoms), combustion products during high-altitude aviation flights and rocket launches, i.e. substances whose molecules contain chlorine or bromine.

These substances, released into the atmosphere at the surface of the Earth, reach the top within 10-20 years. ozone layer boundaries. There, under the influence of ultraviolet radiation, they decompose, forming chlorine and bromine, which, in turn, interact with stratospheric ozone, significantly reducing its amount.

Causes of destruction and depletion of the Earth's ozone layer.

Let us consider again in more detail the reasons for the destruction of the Earth's ozone layer. At the same time, we will not consider the natural decay of ozone molecules. We will focus on human economic activity.