The greenhouse effect is the process by which greenhouse gases absorb and re-radiate thermal radiation, leading to a higher average surface temperature on Earth. Key greenhouse gases include water vapor, carbon dioxide, methane, and ozone, with human activities like fossil fuel burning and deforestation significantly contributing to their increase in the atmosphere. To mitigate the greenhouse effect, individuals can adopt practices such as carpooling, recycling, planting trees, and using energy-efficient products.