Knowledge of global warming

About global warming is now said and written a lot. Almost every day there are no new hypothesis, refuted the old. We were constantly afraid of, what awaits us in the future (I well remember a comment of one of the readers of the magazine  «We are so long and terribly afraid that no longer afraid"). Many statements and articles openly contradictory, misleading. Global warming for many has become a "global confusion", and some have lost all interest in climate change. Let's try to systematize the existing information, creating a kind of mini encyclopedia of global warming.

1. What is global warming?

2. Methods for obtaining information on climate change

3. Evidence of Global Warming

4. Causes of global warming

5. Man and the greenhouse effect

6. Factors that accelerate and slow down global warming

7. Possible scenarios of global climate change

8. The consequences of global warming

9. Methods of preventing global warming

1. Global warming - the gradual increase in the average annual temperature of the surface layer of the Earth's atmosphere and ocean, so all sorts of reasons (increasing the concentration of greenhouse gases in the atmosphere, changes in solar or volcanic activity, etc.). Very often, as a synonym for global warming, use the phrase "the greenhouse effect", but between these concepts there is a small difference. The greenhouse effect - is to increase the average annual temperature of the surface layer of the Earth's atmosphere and of the oceans due to the increase in the Earth's atmosphere concentrations of greenhouse gases (carbon dioxide, methane, water vapor, etc.). These gases act as foils or glass greenhouses (greenhouse), they are free to pass the sun's rays to the Earth's surface and trap heat, leave the planet's atmosphere. In more detail, this process will be discussed below.

For the first time on global warming and the greenhouse effect have started talking in the 60s of XX century, and at the UN level, the problem of global climate change, first announced in 1980. Since then, on this issue are scratching their heads, many scientists have often mutually refuting the theory and assumptions of each other.

2. Methods for obtaining information on climate change

Existing technologies allow to reliably judge the climate change taking place. Scientists in justifying their theories of climate change using these "tools":

- Historical annals and chronicles;

- Meteorological observations;

- Satellite measurements of ice area, vegetation, climate zones and atmospheric processes;

- Analysis of the fossil (the remains of ancient plants and animals) and the archeological data;

- Analysis of oceanic sedimentary rocks and sediments of rivers;

- Analysis of ancient ice in the Arctic and Antarctica (the ratio of O16 and O18 isotopes);

- Measurement of the speed of melting glaciers and permafrost, the intensity of the formation of icebergs;

- Observation of the Earth's ocean currents;

- Monitoring of the chemical composition of the atmosphere and ocean;

- Monitoring changes in habitat (habitat) of living organisms;

- Analysis of tree rings and the chemical composition of plant tissues.

3. Evidence of Global Warming

Paleontological evidence indicates that Earth's climate has not been constant. Warm periods were followed by cold glacial. In warmer periods of the annual average temperature of the Arctic latitudes it rose to 7 - 13 ° C, and the temperature of the coldest month of January is 4-6 degrees, ie, climatic conditions in our Arctic differed little from the contemporary climate of Crimea. In place of the warm periods, sooner or later come cooling, during which the ice reached a modern tropical latitudes.

The man was also a witness to a number of climate change. At the beginning of the second millennium (11-13 century), historical records show that most of Greenland area has not been covered by ice (which is why the Norwegian sailors dubbed it "green earth"). Then the Earth's climate became more severe, and Greenland is almost entirely covered with ice. In the 15-17 century, the harsh winter at its peak. Severe winters that time show many historical records and works of art. So on the famous painting by Dutch artist Jan van Goyen "Skaters" (1641) shows the mass skating on the canals of Amsterdam, the Netherlands is currently feeds a long time ago do not freeze. In medieval winter freeze even the River Thames in England. In the 18th century, it was noted a slight warming, which peaked in 1770. The 19th century was marked again the next cold snap, which lasted until 1900, and since the beginning of the 20th century has already begun a pretty rapid warming. By 1940, the number of the Greenland Sea ice has decreased by half, in the Barents - by almost a third, and in the Soviet sector of the Arctic ice area in the amount reduced by almost half (1 million km2.). During this time, even ordinary court (not ice-breakers) quietly sailed the Northern Sea Route from the western to the eastern border regions of the country. It was then recorded a significant increase in the temperature of the Arctic seas, was a significant retreat of glaciers in the Alps and the Caucasus. The total area of ​​the Caucasus ice has decreased by 10%, and the thickness of ice in some places fell on the whole 100 meters. Raising the temperature in Greenland was 5 ° C and 9 all Svalbard ° C.

In 1940, warming was replaced by a short-term cooling, soon to replace that, it's another warming, and since 1979 has been a rapid increase in the temperature of the surface layer of the Earth's atmosphere, which caused another acceleration of the melting of ice in the Arctic, Antarctic and increasing winter temperatures in temperate latitudes. So, over the past 50 years, the thickness of Arctic sea ice has decreased by 40%, and the inhabitants of a number of Siberian cities began to celebrate themselves, hard frosts that have long been in the past. The average winter temperature in Siberia rose by almost ten degrees in the last fifty years. In some areas of Russia frost-free period increased by two to three weeks. Habitat of many living organisms shifted to the north after the rising average winter temperatures, these and other effects of global warming we talk nizhe. Osobenno clearly about global climate show old photographs of glaciers (all photos made in the same month).

Melting glaciers in Austria

Photo of melting glacier Pasterze in Austria in 1875 (left) and 2004 (right). Photographer Gary Braasch

Agassiz Glacier

Photos Agassiz glaciers in Glacier National Park (Canada) in 1913 and 2005. Photographer W.C. Alden

Melting Glacier Grinnell

Photo Grinnell Glacier in Glacier National Park (Canada) in 1938 and 2005. Photographer: Mt. Gould.

Melting Glacier Grinnell

The same glacier Grinnell from another angle, photos 1940 and 2004. Photographer: K. Holzer.

In general, over the last hundred years, the average temperature of the surface layer of the atmosphere has increased by 0.3-0.8 ° C, snow cover in the northern hemisphere has decreased by 8%, while the sea level has risen by an average of 10-20 centimeters. These facts cause a certain concern. Stop global warming, or whether a further increase in the average temperature on Earth will continue, the answer to this question will appear only when there are well established causes of the climate changes.

4. Causes of global warming

So far scientists have not with certainty can say 100%, causing climate change. As the causes of global warming put forward many theories and assumptions. Here are the main noteworthy, hypothesis. On the other hypotheses can be found on our forum. There you can share your vision of the problem of global warming.

Hypothesis 1 cause of global warming is the change in solar activity

All ongoing climate processes on the planet are dependent on the activity of our star - the sun. Therefore, even small changes in solar activity will certainly affect the Earth's weather and climate. There are 11-year, 22-year-old and 80-90 years old solar activity cycles.

It is likely that the observed global warming is due to another increase in solar activity, which in the future can once again go on the wane.

Hypothesis 2 - cause of global warming - to change the angle of the Earth's axis and its orbit

Yugoslavian astronomer Milankovitch theorized that the cyclical climate change is largely due to changes in Earth's orbit around the Sun, as well as the change in the angle of inclination of the Earth's rotation axis relative to the sun. Similar changes in the orbital position and motion of the planets cause a change in the Earth's radiation balance, and therefore its climate. Milankovitch, guided by his theory, quite accurately calculate the time and the length of the ice ages in the past of our planet. Climate change, caused by changes in the Earth's orbit, typically occur over tens or even hundreds of thousands of years. Also observed at this time point relatively rapid climate change apparently occurs as a result of some more factors.

Hypothesis 3 - The culprit of global climate change - ocean

Oceans - a huge inertia of solar energy battery. It largely determines the direction and speed of the warm ocean, and air masses in the world, which to a large extent affect the planet's climate. At present, little studied the nature of heat circulation in the water column of the ocean. Since it is known that the average temperature of the ocean water is 3,5 ° C, and the land surface 15 ° C, so the intensity of the heat exchange between the ocean and the thickness of the surface layer of the atmosphere can lead to significant climate change. Furthermore, in the ocean dissolved therein large quantities of CO2 (about 140 bln. Tons, 60 times higher than in the atmosphere) and other greenhouse gases as a result of certain natural processes, these gases may be released into the atmosphere, significantly affecting the Earth's climate.

Hypothesis 4 - Volcanic Activity

Volcanic activity is a source of income in the Earth's atmosphere aerosols of sulfuric acid and a large amount of carbon dioxide that can also significantly affect the Earth's climate. Large eruptions are accompanied by original receipts as a result of cooling the Earth's atmosphere sulfuric acid aerosols and soot particles. Subsequently, in the course of the incoming CO2 eruption causes the growth of the average temperature on Earth. Subsequent long-term decline in volcanic activity increases the transparency of the atmosphere, and hence the rise in temperature on the planet.

Hypothesis 5 - unknown interaction between the Sun and the planets of the solar system

In the phrase "solar system" is not for nothing does the word "system", as in any system, as we know, there are links between its components. Therefore, it is possible that the relative position of the planets and the Sun may influence the distribution and strength of gravitational fields, solar energy and other forms of energy. All the communication and interaction between the Sun, the planets and the Earth is not yet known and it is possible that they have a significant influence on the processes occurring in the atmosphere and hydrosphere of the Earth.

Hypothesis 6 - Climate change can occur by itself without any external influence and human activities

Earth is so big and complex system with a large number of structural elements that its global climate characteristics are significantly altered without the changes in solar activity and atmospheric chemistry. Various mathematical models show that for a century, fluctuations in surface air temperature (fluctuations) can reach 0.4 ° C. As a comparison, the healthy human body temperature, which varies during the day, and even hour.

Hypothesis 7 - All because of a man

The most popular to date hypothesis. High speed of climate change occurring in the last decade, can actually be explained ever-increasing intensification of human activity, which has a significant impact on the chemical composition of the atmosphere of our planet in the direction of increasing the content of greenhouse gases in it. Indeed the increase in average temperature of the lower layers of the Earth's atmosphere on a 0.8 ° C over the past 100 years - is too high for the speed of the natural processes, such changes earlier in Earth's history occurred for thousands of years. Recent decades have added even more weight to this argument, since the change in average temperature occurred even more rapidly - 0,3-0,4 ° C over the last 15 years!

It is likely that taking place now global warming is the result of many factors. On the other hypotheses, global warming is happening, you can find here.

5.Chelovek and Greenhouse Effect

Proponents of this hypothesis, a key role in global warming man who radically changes the composition of the atmosphere, contributing to the growth of the greenhouse effect of the earth's atmosphere.

The greenhouse effect in the atmosphere of our planet due to the fact that the flow of energy in the infrared range of the spectrum, rising from the earth's surface is absorbed by molecules of atmospheric gases and radiated back in different directions, resulting in half of the absorbed molecules of greenhouse energy gas is returned to the Earth's surface, causing it heating. It should be noted that the greenhouse effect - a natural atmospheric phenomenon. If the world did not have the greenhouse effect, the average temperature of our planet would be about -21 ° C, and, thanks to greenhouse gases, it is + 14 ° C. Therefore, theoretically, human activities are the result of greenhouse gases in the Earth's atmosphere, should lead to further heating up the planet.

Let's get acquainted with more greenhouse gases, could potentially cause global warming. Greenhouse gas number one is water vapor, its contribution to the existing atmospheric greenhouse effect is 20.6 ° C. In second place is CO2, its contribution is about 7,2 ° C. Growth in the atmosphere of carbon dioxide of the Earth is now causing the greatest concern, as the growing use of an active hydrocarbon humanity continue in the near future. Over the past two and a half centuries (from the beginning of the industrial era) the CO2 content in the atmosphere has increased by about 30%.

In third place is our "greenhouse rating" is ozone, its contribution to the overall global warming of 2,4 ° C. Unlike other greenhouse gases by human activities contrary causes a decrease in ozone in the Earth's atmosphere. This is followed by nitrous oxide, its contribution to the greenhouse effect is estimated at 1,4 ° C. The content of nitrous oxide in the atmosphere has a tendency to rise over the past two and a half century, the concentration of this greenhouse gas in the atmosphere has increased by 17%. A large amount of nitrous oxide to the atmosphere of the Earth at different waste incineration. List of the main greenhouse gas, methane is completing his contribution to the total greenhouse effect is 0.8 ° C. The content of methane in the atmosphere is growing very rapidly, two and a half centuries, the increase was 150%. The main sources of methane are degradable waste into the Earth's atmosphere, cattle, and the breakdown of natural compounds, containing in its composition methane. Of particular concern is that the ability to absorb infrared radiation per unit of mass of the methane is 21 times higher than that of carbon dioxide.

The biggest role in an ongoing global warming discharged water vapor and carbon dioxide. They account for over 95% of the total greenhouse effect. It is because of these two gaseous substances are warming the Earth's atmosphere at 33 ° C. Anthropogenic activities have the greatest impact on growth in the Earth's atmosphere of carbon dioxide and water vapor content in the atmosphere is increasing after the temperature of the planet, due to increased volatility. The total man-made emissions of CO2 in the Earth's atmosphere is 1.8 bln. Tons / year, the total amount of carbon dioxide, which connects the earth vegetation photosynthesis is 43 bln. Tons / year, but almost all of this amount of carbon as a result of plant respiration, fires, decomposition processes again in the planet's atmosphere, and only 45 million tons / year of carbon is deposited in the tissues of plants, swamps land and ocean depths.