Carbon dioxide (chemical formula: CO₂) is a chemical compound that is made up of one carbon atom and two oxygen atoms. It is a colourless, odourless gas that is naturally present in the Earth's atmosphere. Carbon dioxide is released into the atmosphere through various natural processes, such as respiration and the decomposition of organic matter, as well as through human activities, such as the burning of fossil fuels. It plays a crucial role in the Earth's carbon cycle, which regulates the balance of carbon between the atmosphere, land, and oceans. Carbon dioxide is also a greenhouse gas, meaning it traps heat in the atmosphere, contributing to the greenhouse effect and influencing global climate patterns.