What is the greenhouse effect?

What is the greenhouse effect?

• A. Natural situation in which heat is retained in Earth's atmosphere by carbon dioxide, methane, water vapor, and other gases
• B. A man-made barrier to heat loss
• C. The process of heat escaping into space
• D. A phenomenon that cools Earth

Answer: (A)

Heat from the Sun warms Earth, but the atmosphere contains gases such as carbon dioxide, methane, and water vapor that absorb infrared radiation. This absorption traps heat near the surface, so the lower atmosphere and the ground stay warmer than they would be otherwise. This natural trapping keeps Earth at a temperature that supports life, which is what we mean by the greenhouse effect. It isn’t a man-made barrier to heat loss, and it isn’t about heat escaping into space; rather, it reduces the amount of heat that escapes back into space. When human activities raise the levels of these greenhouse gases, more heat is trapped, leading to extra warming beyond the natural level—the enhanced greenhouse effect.

Heat from the Sun warms Earth, but the atmosphere contains gases such as carbon dioxide, methane, and water vapor that absorb infrared radiation. This absorption traps heat near the surface, so the lower atmosphere and the ground stay warmer than they would be otherwise. This natural trapping keeps Earth at a temperature that supports life, which is what we mean by the greenhouse effect. It isn’t a man-made barrier to heat loss, and it isn’t about heat escaping into space; rather, it reduces the amount of heat that escapes back into space. When human activities raise the levels of these greenhouse gases, more heat is trapped, leading to extra warming beyond the natural level—the enhanced greenhouse effect.