Albedo is a measure of the reflectivity of the Earth's surface. It is the fraction of solar energy that is reflected from the Earth's surface back into space.

Climate Feedback

A feedback is the process through which a system is controlled, changed, or modulated in response to its own output. Positive feedback results in amplification of the system output; negative feedback reduces the output of a system.

Climate Forcing

Climate forcing refers to an energy imbalance caused by natural or man-made processes causing an energy imbalance between incoming energy from the Sun and outgoing heat from the Earth.


The cryosphere is the part of the Earth's surface where water is frozen solid, including glaciers, ice sheets, sea and lake ice, snow cover, and permafrost.

Global Climate Change

Global climate change is change recorded over an extended length of time (decades or longer) with regards to precipitation, temperature, or wind caused by natural and/or manmade factors.


The hydrosphere is the water layer of the Earth. About 70% of the Earth's surface is covered with water, most of which is in the oceans. Only a small portion of the Earth's water is freshwater, found in rivers, lakes, and groundwater.


The lithosphere is made up of the Earth's crust and the upper part of the mantle layer underneath. The lithosphere extends about 80 km deep and is broken into giant plates that move and shift, causing earthquakes.


Permafrost is soil at or below the freezing point of water for two or more years.