Final answer:
The greenhouse effect is the natural process of heat retention by Earth's atmosphere, which is intensified by human activities in what is known as the enhanced greenhouse effect. The latter causes more heat to be trapped, leading to global warming and climate change.
Step-by-step explanation:
The greenhouse effect refers to the natural process by which certain gases in Earth's atmosphere trap heat, preventing it from escaping into space, and thus keeping the Earth at a habitable temperature. Sunlight enters the Earth's atmosphere, with some of the energy absorbed and re-emitted as infrared radiation. Although the atmosphere allows most of this incoming visible light to pass through, it absorbs the infrared radiation re-emitted by the Earth, trapping heat. This natural greenhouse effect is critical for sustaining life as we know it.
Conversely, the enhanced greenhouse effect occurs when human activities, particularly the burning of fossil fuels, increase the concentration of greenhouse gases like carbon dioxide, methane, and nitrous oxide. This leads to an imbalance, trapping more heat than usual and causing the Earth's average temperature to rise, contributing to global warming and climate change. The enhanced greenhouse effect hence refers to the human-induced intensification of the natural greenhouse process.
Greenhouse gases vary in their impact on this process. For instance, methane (CH4) is 28 times and nitrous oxide (N2O) is 298 times more effective at trapping heat than carbon dioxide (CO2) over a 100-year period, as indicated by their global warming potential (GWP). These gases, alongside others like fluorinated gases, can have a significant and lasting effect on the Earth's climate system due to their longevity and heat-trapping efficiency.