Question 86 from UPSC CSE 2022 - Geography

Question

Consider the following statements:
1. High clouds primarily reflect solar radiation and cool the surface of the Earth.
2. Low clouds have a high absorption of infrared radiation emanating from the Earth's surface and thus cause a warming effect.
Which of the statements given above is/are correct?

IASCODEX · Accepted Answer

Correct Option: D. Neither 1 nor 2

Strategy: The strategy focuses on comparing the stated roles of high and low clouds with their scientifically established radiative effects. High clouds primarily trap outgoing infrared radiation, causing warming, while low clouds mainly reflect incoming sunlight, leading to cooling. Since the provided statements reverse these conventional roles, both are considered factually incorrect.

Key Info: Clouds significantly influence Earth's climate by affecting both shortwave (solar) and longwave (infrared) radiation.

### High Clouds

High clouds, such as cirrus, are typically thin and found at altitudes above 6 km. They allow most solar radiation to pass through but are highly effective at absorbing and re-emitting longwave infrared radiation emitted from Earth's surface. This process traps heat, resulting in a net warming effect that contributes to the greenhouse effect. Examples include cirrus and cirrostratus clouds.

### Low Clouds

Low clouds, such as stratus and stratocumulus, are generally thick, dense, and located below 2 km. They possess a high albedo, reflecting most incoming solar radiation back into space, which leads to a net cooling effect on the Earth's surface. Their role in absorbing Earth's infrared emission is less significant compared to their reflected solar effect.

The overall climatic impact of clouds depends on their altitude, thickness, and specific type. While high clouds generally tend to warm the planet, low clouds predominantly cool it. These radiative effects are central to climate models and essential for assessments of climate change.

IASCODEX · Answer

Option A: 1 only

IASCODEX · Answer

Option B: 2 only

IASCODEX · Answer

Option C: Both 1 and 2

Consider the following statements: High clouds primarily reflect solar radiation and cool the surface of the Earth. Low clouds have a high absorption of infrared radiation emanating from the Earth's surface and thus cause a warming effect. Which of the statements given above is/are correct?

Consider the following statements:

High clouds primarily reflect solar radiation and cool the surface of the Earth.

Low clouds have a high absorption of infrared radiation emanating from the Earth's surface and thus cause a warming effect.
Which of the statements given above is/are correct?