Global warming is a problem that is actively discussed nowadays. Very often new hypotheses appear about its impact on the Earth and human beings. At first, we need to classify the information available, to create a clear understanding of global warming effect on our planet.
Global warming is the increase in the medium annual temperature of the Earth's atmosphere and oceans, because of much variety of reasons (increasing the concentration of gases in the Earth's atmosphere, solar variability or volcanic activity, etc.) (Haugen 14). Sometimes we use definition "greenhouse effect", but there is some differences between this two concepts. Greenhouse effect leads to increase in average annual temperature of the surface layer of Earth's atmosphere also of the oceans only due to rising concentrations in the atmosphere of greenhouse gas (methane, carbon dioxide, vapor, etc.) (Haugen 21). This gase act as magnifier or greenhouse, which is why they hold heat.
The scientific evidence states that a number of factors could cause global warming (Miller 9-11):
- Volcanic eruptions;
- The behavior of the oceans (typhoons, hurricanes, etc.);
- Solar activity;
- Earth's magnetic field;
- Human activity. The so-called anthropogenic factors. The idea is supported by the majority of scientists, NGOs and the media that does not mean its unwavering truth.
Most likely, it turns out that each of these components contributes to global warming (Miller 12).
Existing technologies give us a clear vision of the climate change. Scientists are using following tools to identify climate change (Nemeth 21):
- Historical annals and chronicles;
- Meteorological observations;
- Satellite measurements of sea ice, vegetation, climatic zones and atmospheric processes;
- Analysis of the fossil (the remains of ancient plants and animals) and archaeological data;
- Analysis of sedimentary rocks and ocean sediments of rivers;
- Analysis of ancient ice in the Arctic and Antarctica (the ratio of isotopes O16 and O18);
- Measurement of the rate of melting of glaciers and permafrost, the intensity of formation of icebergs;
- Observation of the Earth's ocean streams;
- Monitoring of the chemical composition of the atmosphere and ocean;
- Monitoring changes in habitat of living creatures;
Paleontological evidence shows that the Earth's climate was not constant all the time. Warm periods alternated with cold. During warmer periods the annual average temperature of the Arctic latitudes rose to 7 - 13 ° C, and the temperature of the coldest month of January is 6.4 degrees, so climatic conditions in our Arctic climate differed a lot from modern climatic conditions (Nemeth 27).
Human being was also a witness to a number of climate change. At the beginning of the second millennium (11-13 century) historical records indicate that a large area of Greenland was not covered with ice (which is why the Norwegian sailors dubbed her "green land"). Then the Earth's climate became more severe, and Greenland became almost entirely covered with ice. In the 15-17 century, severe winters reached its peak (Seymour 31). At that time, the severity of the winters evidenced by the many historical records, as well as works of art. For example, well-known painting by the Dutch artist Jan van Goyen "Skaters" (1641) represents a mass skating on the canals of Amsterdam, nowadays the canals don’t freeze at all. In medieval even the River Thames in England was covered with ice at winter. In the 18th century, it was noted a slight warming, which peaked in 1770 (Simon 32). The 19th century was marked again with the next cold snap, which lasted until 1900, and since the beginning of the 20th century begun a pretty rapid warming (Seymour 33). Already by 1940, the number of the Greenland Sea ice has been halved, in the Barents Sea - by almost a third, and in the Arctic ice area reduced by almost half (1 million. Km2). During this time, even ordinary ships (not iceboats) quietly floated the northern sea route from the western to the eastern outskirts.
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, the area of snow cover in the Northern Hemisphere has decreased by 8%, and the global sea level has risen by an average of 10-20 centimeters (Houghton 8). These facts cause a certain concern. What would happen to a further increase in average annual temperature on Earth? The answer to this question will appear only when the causes of the climate change will be precisely identified.
One of the most popular hypothesis say that the key role in global warming play the humanity who radically change the composition of the atmosphere, contributing to the growth of the greenhouse effect of the atmosphere of the Earth (Schneider 11).
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 the molecules of the atmospheric gases and radiates back apart, resulting in half greenhouse gas molecules absorbed energy is returned back to the earth's surface, causing it heating. It should be noticed that the greenhouse effect is a natural atmospheric phenomenon (Schneider 13). If the world did not have the greenhouse effect, the average temperature of our planet would be about -21 ° C, and due to greenhouse gases, it is + 14 ° C. Therefore, theoretically, human activities, which launch the greenhouse gases in the Earth's atmosphere, should lead to further heating of the planet.
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. Increasing number of carbon dioxide is now causing the greatest concern. Over the past two and a half centuries (from the beginning of the industrial era) the amount of CO2 in the atmosphere has increased by about 30%( Pringle 42).
In third place is ozone, its contribution to the overall global warming is 2,4 ° C. Unlike other greenhouse gases, human activities contrary causes a decrease in ozone in the Earth's atmosphere. Followed by nitrous oxide, its contribution to the greenhouse effect is estimated at 1,4 ° C. The content of nitrous oxide in the atmosphere tends to increase over the past two and a half centuries 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 as a result of combustion of various wastes. Methane completes its contribution to the total greenhouse effect is 0,8 ° C. The volume of methane in the atmosphere is increasing very rapidly over two and a half centuries, by almost 150% (Lerner 51). The main sources of methane in the atmosphere are degradable waste, cattle, and the breakdown of natural compounds, containing methane in its composition (Lerner 52).
The greatest role in an ongoing global warming discharged water vapor and carbon dioxide. They account for over 95% of the total greenhouse effect. It is through these two gaseous substance is heated the Earth's atmosphere at 33 ° C. Anthropogenic activities have the greatest impact on the growth of the Earth's atmosphere. The total manufactured CO2 emissions to the atmosphere of the Earth is 1.8 billion. Tons / year, the total amount of carbon dioxide, which connects the vegetation of the Earth as a result of photosynthesis is 43 billion Tons / year. But almost all of this amount of carbon as a result of plant respiration, fire, decomposition processes in the planet's atmosphere and only 45 million tons / year of carbon that is deposited in the tissues of plants, swamps land and ocean depths. These figures show that human activities could potentially be a tangible force that affects the Earth's climate.
One of the most visible processes related to global warming is melting glaciers.
Over the past half-century temperatures in the south-west of the Antarctic, the Antarctic Peninsula has increased by 2,5 ° C. In 2002, from the Larsen Ice Shelf area of 3250 km and a thickness of over 200 meters, located on the Antarctic Peninsula, the iceberg broke off an area of over 2,500 km, which actually means the destruction of the glacier. The whole process took only 35 days. Prior to this glacier has remained stable for 10 thousand years, from the end of the last ice age (Scherer 25). Over the past thousands years power of the glacier decreased gradually, but in the second half of the XX century, its rate of melting has increased substantially. Melting glaciers led to the release of a large number of icebergs (over a thousand) in the Weddell Sea (Scherer 29) .
Global warming will greatly affect the lives of some animals. For example, polar bears, seals and penguins will be forced to change their place of residence, as the current would melt. Many plants and animal species may simply disappear, unable to adapt to a rapidly changing environment (Weart 14). The weather will change on a global scale. Number of climatic disasters is expected to increase; longer periods of extremely hot weather; more rain, but it will increase the probability of drought in many regions; increase in the number of floods due to storms and rising sea levels (Weart 23). However, it all depends on the region.
The report of the working group of the Intergovernmental Panel on Climate Change shows the seven models of climate change in the XXI century. The main conclusions in the report - continued global warming, accompanied by an increase in greenhouse gas emissions; increasing the surface temperature (at the end of the XXI century the surface temperature may increase by 6 ° C); sea level rise up (on average - 0.5 meters per century) (Gaughen 30).
The most likely changes in weather conditions are more intense rainfall events; Higher maximum temperatures, more hot days and fewer frost days in almost all regions of the Earth; while in most continental areas heat waves will become more frequent; reduction of temperature variations.
Because of these changes, you can expect more severe storms and increased intensity of tropical cyclones, an increase in the frequency of heavy precipitation events, increase in drought areas.
Intergovernmental Commission identified a number of areas that are most vulnerable to the expected climate change. This are the areas of the Sahara, the Arctic, Asian mega-deltas, small islands (Gore 43).
The negative changes in Europe include increasing temperatures and increased drought in the south (as a result - reduction of water resources and hydropower reduction, reduction of agricultural production, deterioration in the terms of tourism), reductions in snow cover and retreat of mountain glaciers, increasing the risk of flash floods and catastrophic floods on the rivers; increased summer precipitation in Central and Eastern Europe, the increase in the frequency of forest fires, fires in peat lands, reducing the productivity of forests; increase the instability of soils in Northern Europe (Weisel et al. 16). The Arctic - a catastrophic decrease in the area glaciation, the shrinking of sea ice, increased coastal erosion.
Some researchers offer a pessimistic forecast, according to which in the first quarter of the XXI century is possible sharp rise in climate, which can lead to the beginning of a new ice age period of hundreds of years.
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