Previous Year Question
Without green house effect, the average temperature of earth surface would be
0°C
–18°C
5°C
5°C
Correct Answer: B
Detailed Solution
The Natural Greenhouse Effect plays an extremely important role in maintaining Earth's surface at a temperature suitable for life.
A portion of the energy received from the Sun is absorbed by Earth's surface. The warmed Earth then emits this energy back towards space as long-wave infrared radiation.
Greenhouse Gases such as Water Vapour, Carbon Dioxide (CO₂), Methane (CH₄), Nitrous Oxide (N₂O) and Ozone (O₃) absorb a portion of this outgoing infrared radiation and re-emit it in different directions. Some of this energy returns towards Earth's surface and keeps the surface and lower atmosphere warm.
In the absence of the natural Greenhouse Effect, Earth's average surface temperature would be approximately 255 Kelvin, or about –18°C. Due to the natural Greenhouse Effect, Earth's average surface temperature remains around +15°C.
Thus, the Natural Greenhouse Effect keeps Earth approximately:
15°C – (–18°C) = 33°C
warmer.