Given below are two statements:
Statement I: Earth's atmosphere acted like a greenhouse to capture the Sun's heat, which led to the emergence of life forms on Earth.
Statement II: Today the atmosphere is not able to trap the Sun's heat because of the presence of carbon dioxide, nitrogen oxide, methane and other gases.
In the light of the above statements, choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Statement I is true but Statement II is false
The greenhouse effect is the trapping of heat by gases in the atmosphere: sunlight passes through the air and warms the surface, and gases such as carbon dioxide, water vapour and methane absorb the heat the surface gives off and keep part of it in.
Statement I: Earth’s atmosphere acted like a greenhouse to capture the Sun’s heat, which led to the emergence of life forms on Earth. Correct. Because of this natural greenhouse effect, the Earth’s average surface temperature is about 15°C instead of about −18°C, warm enough for liquid water and life.
Statement II: Today the atmosphere is not able to trap the Sun’s heat because of the presence of carbon dioxide, nitrogen oxide, methane and other gases. Incorrect. These are the very greenhouse gases that trap heat; their rising amounts make the atmosphere trap more heat, not less, which is the cause of global warming.