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. A. I and III only
2. B. I and II only
3. C. I, II and III
4. D. II and III only

Answer: C

Explanation

All three statements are correct and describe the crucial role of Earth’s atmosphere in regulating temperature. I. Without the atmosphere, Earth would experience extreme temperature fluctuations, with surface temperatures dropping drastically below freezing, similar to the Moon. The atmosphere acts as an insulating blanket. II. The atmosphere, through the natural greenhouse effect, absorbs and traps outgoing longwave radiation from the Earth’s surface. This trapped heat is vital for maintaining our planet’s average temperature at a level suitable for life. III. Certain atmospheric gases, known as greenhouse gases, such as carbon dioxide, methane, and water vapor, are particularly effective at absorbing and re-emitting infrared radiation. This property is central to the atmosphere’s ability to trap heat. Understanding the composition and functions of the atmosphere is a fundamental topic in UPSC Geography and Environment & Ecology.