The main cause of global climate change, also known as global warming, is the increase in concentrations of greenhouse gases in the Earth's atmosphere, primarily carbon dioxide (CO2) from burning fossil fuels like coal, oil, and gas. When we burn these fossil fuels for energy, we release large amounts of CO2 and other greenhouse gases into the atmosphere, trapping heat from the sun and causing the Earth's temperature to rise.
Other human activities that contribute to global climate change include deforestation, agriculture, transportation, and industrial processes. Deforestation releases carbon stored in trees, reduces the amount of carbon that can be absorbed by the Earth's forests, and alters the Earth's albedo (reflectivity), leading to more heat absorption. Agriculture contributes to global climate change through emissions of methane from livestock and from the use of fertilizers that release nitrous oxide. Transportation releases CO2 and other greenhouse gases through the burning of fossil fuels in vehicles. Industrial processes also release greenhouse gases through the burning of fossil fuels and other activities.
Natural factors such as volcanic activity and changes in solar radiation can also affect the Earth's climate, but the overwhelming scientific evidence indicates that human activities are the primary cause of global climate change.