Question

Without green house effect, the average temperature of earths surface would have been :

• A. $-{18}^{\circ }C$
• B. ${33}^{\circ }C$
• C. $0^{\circ }C$
• D. ${15}^{\circ }C$

Answer 1

The correct option is A $-{18}^{\circ }C$

If an ideal thermally conductive black body were the same distance from the Sun as the Earth is, it would have a temperature of about 5.3 C. However, since the Earth reflects about 30% of the incoming sunlight, this idealized planet's effective temperature (the temperature of a black body that would emit the same amount of radiation) would be about 18 C. The surface temperature of this hypothetical planet is 33 C below Earth's actual surface temperature of approximately 14 C. The mechanism that produces this difference between the actual surface temperature and the effective temperature is due to the atmosphere and is known as the greenhouse effect.
Thus Option A is correct.