The main gas responsible for climate change is carbon dioxide (CO2), a greenhouse gas that traps heat in the Earth’s atmosphere. Increased concentrations of CO2 are primarily a result of human activities, including burning fossil fuels like coal, oil, and natural gas, as well as deforestation. Other greenhouse gases, such as methane and nitrous oxide, also contribute to climate change, but CO2 is the most significant due to its abundance and long atmospheric lifespan. Efforts to mitigate climate change focus heavily on reducing CO2 emissions to achieve a sustainable future.