Paleontological Research Institution and its Museum of the Earth
Climate change refers to variations over time in a number of factors that make up Earth's climate system.

The fundamental driver of this system is the sun, from which Earth receives continuous heat (and light). When this heat reaches the Earth’s atmosphere it can be reflected in the atmosphere or at the surface of the Earth and scattered back into space (step 2 below), or it can be absorbed by the atmosphere or surface of the Earth and enter the climate system (step 3) through what is known as the greenhouse effect (steps 4 and 5).
The greenhouse effect stabilizes the Earth’s temperature and keeps it from moving too far in one direction or another. Over long periods of time however, the temperature does change, usually very slowly.

The atmosphere is just one component of Earth’s climate system; the other components and their interactions are shown below. Click on each element to see the role it plays in shaping Earth’s climate.
Many people today automatically associate climate with energy, and assume that the two are linked. This is not necessarily the case, however. The term ‘energy’ has many connotations; in common usage, it usually refers to energy resources, such as natural gas, oil, or coal, which can be processed to provide us with electricity and other forms of power. We tend to equate energy with climate because it is use of these energy resources that has generated changes.
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