The Need for the Greenhouse Effect Write-up
The greenhouse effect is one important difference that differentiates Earth from other planets in the solar system and makes life on Earth possible. It has a great impact on various aspects of life on Earth, ranging from the climate to the basic needs of living things.
Without the greenhouse effect, Earth would be much like Mars and too cold for life. The atmosphere of Mars is not thick enough to reflect sufficient heat back to the planet, resulting in a very low temperature on Mars. The same would happen on Earth without the greenhouse effect. The temperatures would be very low, and although people may be able to survive, animals and plants that cannot adapt to the low temperatures would not survive, and much-needed water would be frozen and difficult to obtain. Thus, without the greenhouse effect, it would be difficult to sustain life on Earth.
The greenhouse effect is vital to life on Earth for many reasons. Firstly, the greenhouse effect keeps the Earth’s temperature in a suitable range. During this process, the greenhouse gases in the atmosphere allow solar radiation from the sun to pass through and be absorbed by the Earth’s surface. At the same time, infra-red radiation emitted by the Earth’s surface is re-emitted back to Earth. Thus, greenhouse gases function as effective global insulators and keep the Earth warm in two ways, firstly by allowing solar radiation to pass through and warm the Earth, and secondly, by slowing the escape of heat. The greenhouse effect thus raises the average surface temperature of the Earth by about 33oC and keeps the Earth warm. With the greenhouse effect in place, the bodies of most living things are able to function normally at temperatures that are neither too hot nor too cold. The warmth that results from the greenhouse effect is not only a vital requirement for life on Earth, but also aids in satisfying another important need – water.
Temperature range provides water for life on Earth. As a result of the greenhouse effect, the temperature of the Earth falls between the freezing point of water and its boiling point, such that much of the water on Earth does not evaporate or freeze but remains accessible and usable to life on Earth. This satisfies the need of most living things for water.
Thus, by satisfying the vital needs of living things on Earth, the greenhouse effect aids in sustaining life. It provides the warmth and water required for life to flourish on Earth, and in effect sustaining our ecosystem and biosphere.
Another way in which the greenhouse effect affects life on Earth is through the role it plays in the Earth’s climate. By balancing the solar radiation absorbed from the sun with the infra-red radiation emitted by the Earth’s surface and atmosphere, the greenhouse effect keeps the Earth’s temperature in a stable state and prevents sudden and rapid heating or cooling. Thus, the incoming and outgoing radiation is well-balanced and the climate of the Earth is fairly regulated. The resultant warmth on Earth is also an important stimulus of its climate as it causes water to evaporate, condense and form rain, snow, sleet etc.
However, an enhancement of the greenhouse effect has dire consequences. An excess of greenhouse gases in the atmosphere will lead to what is known as the enhanced greenhouse effect. This will cause excessive heat to be trapped and absorbed, resulting in a dramatic increase in the average surface temperature of the Earth, a phenomenon known as global warming. Among other things, this will lead to many natural disasters such as droughts, floods etc. (To find out more, please refer to the report on the enhanced greenhouse effect.)
For more information on some of the terms used in this entry, visit the category Glossary of Terms.
