Which phenomenon describes heat trapped in Earth's atmosphere causing warming?

• A. Kyoto Protocol
• B. Greenpeace
• C. Greenhouse Effect
• D. Bollywood

Answer: (C)

Heat trapped in Earth's atmosphere causing warming is described by the greenhouse effect. Sunlight reaches the surface and heats it, while the surface emits infrared radiation. Greenhouse gases such as carbon dioxide, methane, nitrous oxide, and water vapor absorb much of that infrared heat and radiate it back toward the surface, warming the lower atmosphere and the planet as a whole. This natural process keeps Earth warmer than it would be otherwise, but human activities are increasing the concentrations of these gases, amplifying the effect and driving recent warming. The other options don’t describe a physical heat-trapping process: one is an international treaty to reduce emissions, another is an environmental advocacy group, and the last is a film industry.