What does the greenhouse effect describe?

The greenhouse effect specifically describes the warming of Earth's surface that occurs when greenhouse gases, such as carbon dioxide and methane, trap heat in the atmosphere. This phenomenon is a natural process that helps maintain the planet's temperature, making it suitable for life. Sunlight enters the Earth's atmosphere, and some of it is absorbed by the surface, which then radiates the energy back into the atmosphere as infrared radiation. Greenhouse gases absorb this radiation and re-radiate it in all directions, including back towards the Earth. This effectively warms the lower atmosphere and the surface, leading to the average global temperatures we experience.

Understanding this process is crucial, as it plays a significant role in climate regulation. An increase in greenhouse gases, primarily from human activities such as burning fossil fuels and deforestation, enhances this natural effect, leading to global warming and climate change. This is distinctly different from the other choices, which do not relate to this specific mechanism of heat retention within the atmosphere.