Atmosphere’s role in Earth’s temperature — UPSC Prelims PYQ 2025

Consider the following statements:

1. Without the atmosphere, the temperature would be well below the freezing point everywhere on the Earth’s surface.
2. Heat absorbed and trapped by the atmosphere maintains our planet’s average temperature.
3. Atmosphere’s gases, like carbon dioxide, are particularly good at absorbing and trapping radiation.

Which of the statements given above are correct?

1. I and III only
2. I and II only
3. I, II and III
4. II and III only

Explanation

Statement I is incorrect

• Without an atmosphere, Earth would have huge temperature fluctuations between day and night, like the Moon. Daytime temperatures would be hundreds of degrees Celsius above normal, and nighttime temperatures would be hundreds of degrees below normal.

Statements II and III are correct

• The heat absorbed and trapped by our atmosphere keeps our planet’s average surface temperature at a balmy 15°C (59°F).
• Some of the atmosphere’s gases, like carbon dioxide, are particularly good at absorbing and trapping radiation. Changes in the amounts of these gases directly affect our climate.

Answer: (d) II and III only; Difficulty Level: Easy