Explain how the Earth’s atmosphere helps in maintaining a suitable temperature for life to survive on the Earth.
The Earth's atmosphere plays two crucial roles in maintaining a suitable temperature for life to survive on our planet.
Firstly, it partly absorbs the incoming solar radiation. The ozone layer blocks the harmful UV rays. Additionally, clouds and other gases absorb some sunlight before it reaches the surface of the Earth, preventing the planet from overheating during the day.
Secondly, the atmosphere traps the outgoing heat. The Earth's surface absorbs sunlight and re-radiates it in the infrared region. Greenhouse gases like CO₂, CH₄, and water vapour absorb this re-radiated heat, preventing it from escaping into space. This keeps the Earth warm enough for life during the night.
Without the atmosphere, the Earth would be too cold for life to survive. However, excess CO₂ from human activities enhances the greenhouse effect, causing global warming.
If left unchecked, global warming could make the Earth uninhabitable. This is evident on Venus, which is hotter than Mercury despite being farther from the Sun, due to an uncontrolled greenhouse effect caused by its atmosphere.
Explanation
The textbook context explicitly outlines two main roles of the atmosphere in temperature regulation: absorbing incoming solar radiation (ozone layer, clouds, gases) and trapping outgoing heat (greenhouse gases absorbing infrared radiation). The answer is structured to highlight these two roles, followed by the consequences of lacking an atmosphere (too cold) and having excess greenhouse gases (global warming, as seen on Venus).