Global warming represent to an average increase in the earth’s temperature, which in turn causes changes in climate. During the past 4.65 billion years of its history, earth has warmed frequently. But at present earth is
facing a rapid warming mainly due to human activities. The average temperature of earth is about 590F (150 C) and during the last century this average has risen by about 10F. By the year 2100, it is believed that the rise would be between 2.5 and 10.40F and this will cause dramatic changes such as rise in sea level, changes in rainfall patterns, wide range of impacts on plants,wildlife and humans.
The trapping of heat energy from the sun by certain gases in the atmosphere leading to the rise in earth’s temperature is known as Green house effect. Therefor these gases are known as green house gases. Some
gases such as water vapour, carbon dioxide, nitrous oxide and methane act as the trap of heat. These gases absorb and reflect infra red waves radiated by earth.By doing so, these gases conserve heat as the glass in a green house does.
The trapping of heat energy from the sun by certain gases in the atmosphere leading to the rise in earth’s temperature is known as Green house effect. Therefor these gases are known as green house gases. Some
gases such as water vapour, carbon dioxide, nitrous oxide and methane act as the trap of heat. These gases absorb and reflect infra red waves radiated by earth.By doing so, these gases conserve heat as the glass in a green house does.
Normally all life on the earth depends on this green house effect. If it does not exist, earth would be cooled, and ice would cover earth from pole to pole. But if the greenhouse effect becomes strong it could make the earth warmer than usual. Even a little extra warming may cause problems for humans, plants and animals
Types of Greenhouse Gases :-
In the environment, greenhouse gases occur (i) naturally or (ii) from human activities. The most important greenhouse gas is carbon dioxide. It reaches the atmosphere due to volcanic eruptions, respiration of animals, burning and decay of organic matter such as plants and animals. Normally carbon-dioxide is
removed by the plants by photosynthesis. Carbon-dioxide is also absorbed into ocean water. But human activities increase the release of carbon dioxide into the atmosphere . The activities include burning of fossil
fuels, solid wastes, wood and wood products to drive vehicles, generate electricity etc.onthe other hand due to deforestation, the number of trees available to absorb carbon-dioxide through photosynthesis has been greatly reduced. Human activities have caused carbon-dioxide to be released to the atmosphere at rates much faster than that at which earth’s natural processes can recycle this gas. There were about 281 molecules of carbon-dioxide per million molecules of air (i.e., parts per million or ppm) in 1750. Today atmospheric carbon-dioxide concentrations are 368 ppm, a 31% increase. Methane traps 20 times more heat than carbon-dioxide. It is emitted during the production and transport of coal, natural gas and oil. It is
also emitted from rotting organic waste in sand fills, by the cows as a by product of digestion. Since 1750, the amount of methane in the atmosphere has more than doubled.nNitrous Oxide traps 300 times more heat than carbon-dioxide. burning fossil fuels and ploughing farm soils releases nitrous oxide. Since 1750 its level increased by 17%. Hydrocarbons formed from the manufacture of foams, coolants such as chlorofluorocarbons used in refrigerators are the other gases responsible for global warming. In 2000, scientists discovered an alarming increase in the level of a new gas called trifluoromethyl sulphur penta fluoride. Eventhough the gas is rare, it traps more effectively than all other greenhouse gases. The saddest part of it is that the industrial source of the gas is not yet identified.
Effects of Global warming :-
1. Due to the global warming of oceans, sea level will rise.The glacier ice will also melt, causing further rise in sea level. As a result in the 21st century the sea level will rise from 9 to 88 cm. Such a rise will submerge many parts of earth.
2. Various seasons will be longer in some areas.
3. The warmed world will be generally more humid and greater humidity will change the rainfall pattern.
4. Storms and strong winds are expected to be more frequent and intense.
5. Some parts of the world would become dry.
6. Wind blows will be harder and in different patterns and hurricane would be more severer.
7. Weather patterns would be less predictable and more extreme.
8. Crops and forests may be affected by more pest and plant diseases.
9. Animals and plants will find it difficult to adjust to the changed environment and will tend to migrate toward the poles and toward higher elevations.
10. Some types of forests may disappear from earth.
11. More people will get sick or die from heat stress.
12. Tropical diseases such as malaria, dengue fever, yellow fever and encephalitis will spread to other parts of the world.
In the environment, greenhouse gases occur (i) naturally or (ii) from human activities. The most important greenhouse gas is carbon dioxide. It reaches the atmosphere due to volcanic eruptions, respiration of animals, burning and decay of organic matter such as plants and animals. Normally carbon-dioxide is
removed by the plants by photosynthesis. Carbon-dioxide is also absorbed into ocean water. But human activities increase the release of carbon dioxide into the atmosphere . The activities include burning of fossil
fuels, solid wastes, wood and wood products to drive vehicles, generate electricity etc.onthe other hand due to deforestation, the number of trees available to absorb carbon-dioxide through photosynthesis has been greatly reduced. Human activities have caused carbon-dioxide to be released to the atmosphere at rates much faster than that at which earth’s natural processes can recycle this gas. There were about 281 molecules of carbon-dioxide per million molecules of air (i.e., parts per million or ppm) in 1750. Today atmospheric carbon-dioxide concentrations are 368 ppm, a 31% increase. Methane traps 20 times more heat than carbon-dioxide. It is emitted during the production and transport of coal, natural gas and oil. It is
also emitted from rotting organic waste in sand fills, by the cows as a by product of digestion. Since 1750, the amount of methane in the atmosphere has more than doubled.nNitrous Oxide traps 300 times more heat than carbon-dioxide. burning fossil fuels and ploughing farm soils releases nitrous oxide. Since 1750 its level increased by 17%. Hydrocarbons formed from the manufacture of foams, coolants such as chlorofluorocarbons used in refrigerators are the other gases responsible for global warming. In 2000, scientists discovered an alarming increase in the level of a new gas called trifluoromethyl sulphur penta fluoride. Eventhough the gas is rare, it traps more effectively than all other greenhouse gases. The saddest part of it is that the industrial source of the gas is not yet identified.
Effects of Global warming :-
1. Due to the global warming of oceans, sea level will rise.The glacier ice will also melt, causing further rise in sea level. As a result in the 21st century the sea level will rise from 9 to 88 cm. Such a rise will submerge many parts of earth.
2. Various seasons will be longer in some areas.
3. The warmed world will be generally more humid and greater humidity will change the rainfall pattern.
4. Storms and strong winds are expected to be more frequent and intense.
5. Some parts of the world would become dry.
6. Wind blows will be harder and in different patterns and hurricane would be more severer.
7. Weather patterns would be less predictable and more extreme.
8. Crops and forests may be affected by more pest and plant diseases.
9. Animals and plants will find it difficult to adjust to the changed environment and will tend to migrate toward the poles and toward higher elevations.
10. Some types of forests may disappear from earth.
11. More people will get sick or die from heat stress.
12. Tropical diseases such as malaria, dengue fever, yellow fever and encephalitis will spread to other parts of the world.
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