Greenhouse gases are gases in the Earth's atmosphere that trap heat. They include carbon dioxide, methane, and nitrous oxide. These gases allow sunlight to enter the atmosphere but prevent some of the heat from escaping back into space, which helps to keep the planet warm enough to support life. However, human activities, such as burning fossil fuels and deforestation, have increased the concentration of greenhouse gases. This rise contributes to global warming and climate change, leading to various environmental impacts, including rising sea levels and extreme weather events. Reducing greenhouse gas emissions is essential for a sustainable future.