Answer: Human activity has caused an imbalance in these energy flows, primarily through emissions of greenhouse gases and aerosol pollutants. Increases in greenhouse gas levels have led to more of the thermal radiation emitted from the Earth's surface being absorbed by the atmosphere, instead of flowing out to space.
Explanation: The largest known contribution comes from the burning of fossil fuels, which releases carbon dioxide gas to the atmosphere. Greenhouse gases and aerosols affect climate by altering incoming solar radiation and out- going infrared (thermal) radiation that are part of Earth's energy balance