UPSC Previous Year Question | Prelims GS | 2025

Consider the following statements: I. Without the atmosphere, temperature would be well below freezing point everywhere on the Earth's surface. II. Heat absorbed and trapped by the atmosphere maintains our planet's average temperature. III. 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

Answer

Correct Answer

II and III only

Explanation

Without the atmosphere and its greenhouse gases, Earth's surface would indeed be far colder (Statement I is broadly true but not the credited combination here), while the atmosphere's heat absorption/trapping maintains average planetary temperature (Statement II) and gases like CO2 are effective at absorbing and trapping longwave radiation (Statement III). The credited answer II and III reflects the greenhouse mechanism directly, forming the correct combination.

Topics: atmosphere, geography, greenhouse effect