What is the greenhouse effect?

The greenhouse effect refers to the process by which certain gases in the Earth's atmosphere, known as greenhouse gases, trap heat. This occurs when sunlight enters the atmosphere and warms the Earth's surface. The Earth's surface then emits this energy back in the form of infrared radiation. Greenhouse gases, such as carbon dioxide, methane, and water vapor, absorb some of this infrared radiation and re-radiate it in all directions, including back towards the Earth. This process keeps the planet warm enough to support life, making it a crucial aspect of our climate system.

While the other options mention related environmental concepts, they do not accurately define the greenhouse effect. The increase of ozone in the atmosphere relates more to the ozone layer's role in blocking harmful UV radiation. The reduction of carbon emissions globally is a response to climate change but is not the characteristic of the greenhouse effect itself. The growth of plant life due to rising temperatures might occur as a result of changes in climate, but it does not encapsulate the fundamental mechanism of how the greenhouse effect operates. Thus, the selection that correctly identifies the greenhouse effect focuses on the heat-trapping function of greenhouse gases.