Question

Give the names of four greenhouse gases present in the atmosphere.

Answer 1

Gases that absorb and trap energy are referred to as greenhouse gases. The greenhouse gases help in keeping the earth warm. In the absence of greenhouse gases, the earth’s temperature would be as low as -18 degrees Celsius. Planets such as Venus and Mars also contain greenhouse gases in their atmosphere.

Complete answer:
Some points regarding greenhouse gases and greenhouse effect are listed as follows:
- The four greenhouse gases present in the atmosphere are Carbon dioxide $(CO_2)$, Methane $(CH_4)$, Fluorinated gases, and Nitrous oxide $(N_{2}O)$.
- Greenhouse gases absorb infrared radiation emitted from the earth’s surface and reradiate it back. This phenomenon is known as the greenhouse effect.
- The leading source of these gases is from the combustion of fossil fuels and deforestation.
- The efficiency of the gases to retain heat varies from one gas to another. The Global Warming Potential $(GWP)$ is used to measure the ability of a specific gas to absorb energy and to calculate how long it persists in the atmosphere.
- The concentration of greenhouse gases present in the atmosphere is usually measured in parts per million.
- The atmospheric concentrations of greenhouse gases are major indicators of climate change.
- These gases remain in the atmosphere for various periods of time. They can persist in the atmosphere for up to a thousand years.

Note: Water vapour is also considered to contribute to the greenhouse effect. The concentration of greenhouse gases in the atmosphere has been found to marginally increase since the beginning of the Industrial revolution.