Weather, described by temperature, humidity, winds, and precipitation, is ultimately determined by location, topography, and the exchange of radiant energy between the Sun, Earth, and space. Climate is defined as the average weather over various time periods ranging from a few weeks to decades to geological timescales. For the Earth as a whole, this energy transfer must be constant when averaged over annual timescales. Otherwise, the mean temperature of the Earth-atmosphere system must change to establish the equilibrium dictated by thermodynamics.
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The Earth's climate system constantly tries to maintain a balance between the energy from the Sun that is absorbed by the Earth, and the energy that goes from Earth back out to space. Scientists refer to this process as Earth's ΓÇ£radiation budget.ΓÇ¥ The components of the Earth system that are important to the radiation budget are the planet's surface, atmosphere, and clouds.
