A greenhouse is an air-tight glass building that is used extensively by commercial plant growers, gardeners and botanists to grow plants which otherwise would not survive cold weather. Greenhouse buildings are usually used in the countries with cooler climates.
Greenhouse effect is the mechanism by which thermal radiation from earth’s surface is reabsorbed by greenhouse gases and redirected in all directions. Some of the major green house gases are water vapour, carbon dioxide, methane and ozone. Most of these gases are poor absorbers of solar radiation, therefore allowing much of the solar energy to pass through the earth’s atmosphere thereby warming up the earth’s surface. On the other hand, a proportion of the outgoing energy is absorbed by these gases, which is then redirected to earth’s surface therefore further warming up the atmosphere. This is what is called a greenhouse effect. For ages there has been a delicate balance between how much solar energy is redirected to earth and how much is reflected back to the space. With the increased burning of fossil fuels, the percentage of carbon dioxide in the atmosphere has significantly increased thereby adding to the greenhouse effect.
The greenhouse buildings are made mostly of translucent material that offers plants in the building maximum access to sunlight. When the sunlight touches the solid surface inside the greenhouse, the surface absorbs some of the energy and converts it into heat (infrared energy).
While light can easily pass through the glass walls, the infrared energy (heat) cannot escape through the glass walls due to a longer wavelength. Being trapped inside the building, the heat warms the air inside the greenhouse and creates a favorable atmosphere for the plants inside the building.
There are several benefits of a greenhouse. Using this greenhouse advantage, we are growing various crops in an artificial atmosphere. Also, the solar powered water heaters are utilizing the greenhouse effect to warm up waters, saving 20–30% of the energy bills at home.
advantages
Greenhouse gases keep our planet liveable by holding onto some of Earth’s heat energy so that it does not all escape into space. This heat-trapping is known as the greenhouse effect. The greenhouse effect helps to maintain a certain temperature level on Earth’s surface, making it habitable for living beings. Thanks to the greenhouse gases, the earth is warm enough to sustain life.
disadvantages
Since green house gases helps to maintain the temperature, the primary effect of the increase in greenhouse gases would be on climate. This would mean warmer summers with natural disasters. Hurricanes have become common in recent years.
Water level balance of the earth would be destroyed. Polar ice caps would melt leading to an increase in the ocean level. Floods will inundate low lying areas.
Marine life and ecosystem would be destroyed. Oceans absorb carbon dioxide thereby affecting the level of alkalinity. Many forms of marine life would be adversely affected if alkalinity increases. Polar ecosystems would be destroyed. In the Arctic, melting polar caps are threatening the habitats of polar bears and penguins.
Global warming would also affect the weather pattern. Rainfall would become erratic in many parts of the world. This might eventually lead to desertification.
The effect on human and economic life would also be tremendous. It is estimated that the rise in temperature would reduce global output by 2 to 3 percent. This cost would run into trillions of dollars. As agricultural production is affected, this might lead to frequent famines and famine related diseases.
