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Greenhouse Effect

• What is Greenhouse?The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without its atmosphere.If a planet's atmosphere contains radiatively greenhouse gases, the atmosphere will radiate energy in all directions. The part of this radiation is directed towards the surface, warming it. The downward component of this radiation – that is, the strength of the greenhouse effect – will depend on the atmosphere's temperature and on the amount of greenhouse gases that the atmosphere contains.

• HistoryThe existence of the greenhouse effect was argued by Joseph Fourier in 1824. The argument and the evidence was further strengthened by Claude Pouillet in 1827 and 1838, and reasoned from experimental observations by John Tyndall in 1859. The effect was more fully quantified by Svante Arrhenius in 1896. However, the term "greenhouse" was not used to refer to this effect by any of these scientists; the term was first used in this way by Nils Gustaf Ekholm in 1901.In 1917 Alexander Graham Bell wrote "[The unchecked burning of fossil fuels] would have a sort of greenhouse effect", and "The net result is the greenhouse becomes a sort of hot-house. Bell went on to also advocate the use of alternate energy sources, such as solar energy.

• Mechanism The sun radiates solar energy on

earth. The larger part of this energy (45%) is radiated back into space. Greenhouse gases in the atmosphere contribute to global warming by absorption and reflection of atmospheric and solar energy. This natural phenomenon is what we call the greenhouse effect. It is agreed that the greenhouse effect is correlated with global temperature change. If greenhouse gases would not exist earthly temperatures would be below –18 o

It is not physically realistic to assign a specific percentage to each gas because the absorption and emission bands of the gases overlap. The major non-gas contributor to Earth's greenhouse effect, clouds, also absorb and emit infrared radiation and thus have an effect on the radiative properties of the atmosphere.

By their percentage contribution to the greenhouse effect on Earth the four major gases are: • water vapor, 36–70% • carbon dioxide, 9–26% • methane, 4–9% • ozone, 3–7%

• Greenhouse gases

• Role in climate change• Water vapor: The most abundant greenhouse gas, but

importantly, it acts as a feedback to the climate. Water vapor increases as the Earth's atmosphere warms, but so does the possibility of clouds and precipitation, making these some of the most important feedback mechanisms to the greenhouse effect.

• Carbon dioxide (CO2): A minor but very important component of the atmosphere, carbon dioxide is released through natural processes such as respiration and volcano eruptions and through human activities such as deforestation, land use changes, and burning fossil fuels.

• Methane: A hydrocarbon gas produced both through natural sources and human activities, including the decomposition of wastes in landfills, agriculture, and especially rice cultivation, as well as ruminant digestion and manure management associated with domestic livestock. On a

• Nitrous oxide: A powerful greenhouse gas produced by soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning.

• Chlorofluorocarbons (CFCs): Synthetic compounds entirely of industrial origin used in a number of applications, but now largely regulated in production and release to the atmosphere by international agreement for their ability to contribute to destruction of the ozone layer.

• The Effects of Greenhouse :1. The Weather: For greenhouse effect most areas will become

warmer, some areas will become cooler. There may be many storms, floods and drought. no one can predict which area will be effected.

2. Sea Levels: Higher temperatures will make the water of the seas and oceans expand. Ice melting in the Antarctic and Greenland will flow into the sea. All over the world, sea levels may rise, perhaps by as much as 20 to 40 cm, by the beginning of the next century.

3. Farming: The changes in the weather will affect the types of crops grown in different parts of the world. Some crops, such as wheat and rice grow better in higher temperatures, but other plants, such as maize and sugarcane do not.

4.Plants & Animals: It has taken millions of years for life to become used to the conditions on Earth. As weather and temperature changes, the homes of plants and animals will be affected all over the world. Many animals and plants may not be able to cope with these changes and could die.

5.People: The changes in climate will affect everyone, but some populations will be at greater risk. The effect on people will depend on how well we can adapt to the changes and how much we can do to reduce climate change in the world.

• Ways to Reduce Greenhouse Gases1. Reduce, Reuse, Recycle: Buying products with minimal packaging will help to reduce waste. By recycling half of our household waste, we can save 2,400 pounds of carbon dioxide annually.

2. Use Less Heat and Air Condition: Adding insulation to our walls and installing weather stripping or caulking around doors and windows can lower our heating costs more than 25 percent, by reducing the amount of energy we need to heat and cool our home.

3. Replace Your Light Bulbs: Wherever practical, replace regular light bulbs with compact fluorescent light (CFL) bulbs. Replacing just one 60-watt incandescent light bulb with a CFL will save us TK.30 over the life of the bulb.

4. Drive Less and Drive Smart: Less driving means fewer emissions. Besides saving gasoline, walking and biking are great forms of exercise.

5. Buy Energy-Efficient Products: Home appliances now come in a range of energy-efficient models, and compact fluorescent bulbs are designed to provide more natural-looking light while using far less energy than standard light bulbs.

6. Plant a Tree: If we have the means to plant a tree, start digging. Trees absorb carbon dioxide and give off oxygen. A single tree will absorb approximately one ton of carbon dioxide during its lifetime.

7. Encourage Others to Conserve: Share information about recycling and energy conservation with our friends, neighbors and co-workers, and take opportunities to encourage public officials to establish programs and policies that are good for the environment.

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