Earth Science and Geology Practice Exam

Albedo is a measure of surface reflectivity—the fraction of incoming sunlight that a surface reflects back rather than absorbs. High albedo surfaces, like fresh snow or ice, bounce a lot of sunlight, keeping the surface cooler, while low albedo surfaces, such as dark rock or open water, absorb more energy and warm up. This reflectivity plays a key role in climate feedbacks because small changes in surface cover can set off self-reinforcing loops. For example, when ice or snow melts, albedo drops, more solar energy is absorbed, and additional warming accelerates further melting. Clouds also affect albedo by reflecting sunlight, which can cool the surface, though the overall effect depends on cloud properties. Albedo is not related to gravitational field strength or ocean salinity—those describe different physical attributes. Understanding albedo helps explain why changes in land use, ice cover, or cloudiness can lead to meaningful climate responses.