Greenhouse Effect

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A building made chiefly of glass for growing or sheltering the delicate or exotic plants is called Greenhouse. The air in the Greenhouse is warmer then the outside air though it receives less solar radiation. The occurrence of higher temperature inside a Greenhouse then outside even though the interior receives less solar radiation is known as the Greenhouse effect.

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Shorter-wavelength solar radiation from the sun passes through Earth's atmosphere, then is absorbed by the surface of the Earth, causing it to warm.  Part of the absorbed energy is then reradiated back to the atmosphere as long wave infrared radiation.  Little of this long wave radiation escapes back into space;   the radiation cannot pass through the greenhouse gases in the atmosphere. The greenhouse gases selectively transmit the infrared waves, trapping some and allowing some to pass through into space. The greenhouse gases absorb these waves and reemits the waves downward, causing the lower atmosphere to warm

Reasons for greenhouse effect : Three factors contribute to the Greenhouse effect, i.e. warmness in a greenhouse

1. Glass walls, which raise 2. CO2 contents, and 3. Water vapor content of the air in the greenhouse. 4. Methane 5. CFC

Reasons for greenhouse effect …. 

The glass walls high CO2 content and high water vapor content let the solar radiations (wavelength 0.15 to 4 um) pass through them but impede the passage of long wave (infrared) radiation emitted by the earth’s surface. This makes the greenhouse air warmer then the outside air. Gases, such as CO2, methane, Nitrous Oxide, Chloroform Carbons, water vapors, are termed “Greenhouse” gases.

Reasons for greenhouse effect …..

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Methane is added to the atmosphere by marshes, paddy fields, cattle sheds and bio-gas plants. Chloroform carbons are emitted by refrigerators and air conditioners. Nitrogen oxides are produced from organic matter and fertilizers by denitrifying bacteria.

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If the earth had no atmosphere, its average surface temperature would be above - 18oC, the same as that of the moon, which lacks atmosphere. Actually, the average temperature of the earth’s surface is about 15oC. The reason why the earth is warmer then the moon is that it has an atmosphere. The atmosphere absorbs much of the incoming radiation from the sun and reradiates to the earths’ surface, but prevents the earth’s heat to escape into the space. Thus, the atmosphere acts as a Greenhouse, trapping the heat. Man can survive on earth only because of this Greenhouse effect. The natural gases in the atmosphere most responsible for keeping the earth’s surface warm are CO2 and water vapor.

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is adding large amounts of CO2 to the atmosphere each year by burning fossil fuels. This may produce greenhouse effect and may make the earth warmer and change climates. Rise in temperature may melt the polar and alpine snow, and this may raise the sea level and sub merge the coastal areas.

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Rise in temperature would have some other effects also. Climate zones and oceans, currents would shift, agriculture would be displaced, an the worlds major vegetation zones would alter. Another dramatic effect might be thermal expansion of the oceans, causing further rise in sea level. Reforestation can check these eventualities.

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Industries are also increasing the particulate matter. The particulate matter decreases the amount of sunlight reaching the earth. The particles reflect light back into the space. This process decreases the earth’s temperature. A slight fall in the earth’s temperature would bring in another ice age. It seems unlikely that the effects of CO2 and particulate matter would balance. Hence, some change in the world climate may be expected.

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Clouds and dust particles can also produce “Greenhouse effect”. This is cloudy, dusty and humid nights are warmer then the clear, dust free, dry nights.

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Increasing amounts of greenhouse gases in the atmosphere and global warming could also lead to more health concerns.  A statement released from the Intergovernmental Panel on Climate Change (IPCC) said, "Climate change is likely to have wide-ranging and mostly adverse impacts on human health, with significant loss of life."  As temperatures increase towards the poles, similar to farmland, insects and other pests migrate towards Earth's poles. These insects and pests could be allowed to migrate up to 550 Km or 550 miles.  Some insects carry diseases such as malaria and dengue fever.  Thus, an increase in these particular insects and pests closer to the poles results in an increase in these diseases.  This could lead to 50 to 80 million additional cases of Malaria annually, a 10-15% increase.  "Malaria and dengue fever are already beginning to spread pole wards", said Jane Lichens, past president of American Association for the advancement of science.

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Hydro power, currently supplying only six percent of the world's energy, is a renewable energy source. Energy is produced by hydraulic turbines that rotate with the force of rushing water (higher to lower elevation).  It is one of the most clean and cheapest way of producing energy, but it can also change the flow of rivers and increase sediment which kills fish.  It is a large investment for developing countries

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One of the major conventions concerning global warming resulted in the Kyoto Protocol, held in Kyoto, Japan, between December 1-11, 1997. Delegates from all over the world were present in order to find a universal agreement to reduce greenhouse gas emissions.  The results had most developed nations doing most of the reducing; the United States must cut emissions 7%, Japan 6%, and the European Union 8% below 1990 levels.

The United States proposed a plan to have these levels cut over a five year period between 2008-2013.   The United States also said it will not sign the protocol if other developing/undeveloped countries do not sign it as well, fearing the economy will falter.  The U.S. was successful in emissions trading with other countries who have less emissions. This means that the U.S. or other developed countries can purchase emission permits from other countries who have extra permits.  This stresses the importance of flexibility the U.S. was looking for when it said it cannot lower the emission levels until at least 2008.