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.