Explain how the Earth’s atmosphere helps in maintaining a suitable temperature. Class 9

Explain how the Earth’s atmosphere helps in maintaining a suitable temperature. Class 9

Question 1.

Explain how the Earth’s atmosphere helps in maintaining a suitable temperature for life to survive on the Earth. Class 9

Answer:

Two key roles of the atmosphere:

(a) Absorbing Harmful Radiation:

1. The ozone layer in the stratosphere absorbs harmful UV rays from the Sun, protecting living organisms from skin cancer and eye damage.
2. Clouds and gases absorb some sunlight before it reaches the surface, preventing overheating.

(b) Trapping outgoing heat (Greenhouse Effect):

1. The Earth’s surface absorbs solar radiation and re-radiates it as infrared heat back into the atmosphere.
2. Greenhouse gases like CO₂, CH₄ and water vapour absorb this outgoing heat and prevent it from escaping into space.
3. This keeps the Earth’s average temperature at about 15°C, warm enough to support life.
4. Without this greenhouse effect, Earth would be too cold for life to survive.

Atmospheric layers and their roles:

Example from the chapter:

1. Venus has an uncontrolled greenhouse effect due to its thick CO₂ atmosphere, making it hotter than Mercury despite being farther from the Sun.
2. Without any atmosphere, Earth would be like the Moon — extremely hot in sunlight and freezing cold in darkness.