Reflectivity and Albedo

Reflectivity is simply the concept that some surfaces reflect more light while others absorb more light.  Albedo is the measure of the reflectivity of a surface, measuring the percentage of solar radiation reflected and absorbed.  Something with high albedo means it reflects a majority of the light that hits it.

Source: NC State Climate Education K-12

Urban environments have very low albedos because of the amount of tarmac and buildings.  This causes what is known as an urban heat island, where urban areas experience warmer temperatures than the rural areas surrounding them.

Souce: EPA

Different surface types on Earth have differing albedos.

Source: CoCoRaHS

Ice and snow have high albedos and therefore reflect a large amount of light and heat energy from the sun.  When we consider that, as stated in the previous post, seasonal snow covers up to 33% of Earth's surface and ice sheets and glaciers cover an additional 10% of Earth's surface, we can conclude that these surfaces help the Earth reflect a great amount of solar radiation back into space. This prevents the Earth from absorbing more solar radiation and helps keep Earth's surface cooler. Human activity can greatly alter the surface of the Earth, and therefore can greatly alter it's albedo.

What happens to Earth's albedo when, as we know from the previous post, surface ice cover starts decreasing?