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How do Earth’s surface albedo and cloud cover affect the amount of sunlight Earth absorbs?

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Illustration of various geoengineering techniques to address climate change, including carbon capture and storage methods like artificial trees, industrial scrubbers, and deep ocean CO2 storage, as well as solar reflectance strategies such as sulfur aerosols, reflective crops, cloud whitening, and orbital mirrors. The scene shows these interventions applied to land, sea, and atmosphere, with labeled features explaining each process. — Geoengineering Various geoengineering proposals designed to increase solar reflectance or capture and store carbon.

Earth’s surface albedo and cloud coverage are primary mechanisms that control how much solar radiation is absorbed by the planet versus reflected back into space.1

Surface Albedo

Albedo refers to the reflectivity of a surface. Surfaces with high albedo, such as fresh snow, reflect a large proportion of incoming shortwave radiation, keeping the surface cool. Conversely, dark surfaces like forests or organic soils have low albedo and absorb more solar energy. Changes in land cover, such as deforestation or desertification, can significantly alter regional albedo, thereby impacting local climate and rainfall patterns. In the Arctic, the melting of sea ice creates a positive feedback loop: as reflective ice disappears, it exposes darker water that absorbs more sunlight, which in turn accelerates further melting.2345

Cloud Cover

Clouds play a critical role in the Earth's energy budget by reflecting incoming sunlight. When tall, thick clouds are present, they can reflect up to 80 percent of insolation back into space, significantly reducing the amount of energy that reaches the surface.13