Here's why:

* Clouds are highly reflective: Clouds are composed of water droplets or ice crystals, which reflect sunlight back into space. This is why we see clouds as white - they're reflecting a large portion of the incoming sunlight.

* Earth's surface is less reflective: The Earth's surface has varying reflectivity (albedo). While some surfaces like snow and ice are highly reflective, others like forests and oceans absorb more sunlight.

Overall, clouds reflect a significantly larger amount of solar radiation back to space compared to the Earth's surface. This effect is crucial for regulating Earth's temperature.