When the Earth’s atmosphere captures the radiation energy from the sun, warming the Earth’s surface, it is called global warming. The greenhouse effect helps reduce heat loss by radiation from the Earth’s surface. The greenhouse effect is due to the presence of CO2, water vapor, ozone, methane, nitrous oxide, and halogenated carbons in the atmosphere. Without these gases or their effect, the average temperature on Earth would be, -18°C instead of +15°C.
Greenhouse Effect Explained!
The energy from the sun will be in the form of solar radiation. This radiation to the earth is absorbed by various atmospheric gases in the stratosphere. These compounds absorb the radiation in varying amounts depending on their wavelength.
Oxygen and ozone absorb the radiation which has a wavelength of 0.3𝜇m. The remaining radiation or a major portion of solar radiation passes through. This is later absorbed by the oceans and land.
The absorbed energy will be reradiated back to the atmosphere in the form of infrared radiation with long waves. Various atmospheric gases, such as carbon dioxide. nitrous oxide, methane, and water vapour absorb this reradiated energy. Such compounds that absorb this infrared radiation with a longer wavelength of 4𝜇m are called greenhouse gases.
As a result of the absorption of the radiation by the greenhouse gases, the energy is radiated back to the Earth as heat. This way, the greenhouse gases function as a thermal blanket over the Earth and cause an increase in the overall temperature of the Earth. This increase in temperature due to greenhouse gases is called the greenhouse effect.
The greenhouse effect occurs naturally, and without these greenhouse gases, the reradiated heat would have escaped into space causing a drop in the earth’s temperature up to a freezing level. The redirection of heat by the greenhouse gases keeps the earth’s temperature regulated.
References
- Girardon, P. (2019). Sustainable development. In Elsevier eBooks (pp. 669–673). https://doi.org/10.1016/b978-0-12-812465-9.00028-1
- Shukla, R.S. and Chandel, P.S. (2001) Plant Ecology. S. Chand and Company Ltd., New Delhi.
- Verma, P.S., Agarwal, V.K. (1999). Cell Biology, Genetics, Molecular Biology, Evolution, and Ecology. New Delhi: S.Chand Co.(Pvt) Ltd.
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