Earth’s Energy Budget

Watch the video to see how everything you have learned about works together to create Earth’s Energy Budget. This energy budget is the main determinant of climate.

Chart Source: Earth’ Energy Budget | WikiMedia

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Recall that the Earth both absorbs and emits energy in the form of radiation. When Earth is in equilibrium, it returns an equal amount of energy back to space by reflecting some incoming light and by radiating heat. We call this, Earth’s energy budget. Let’s take a closer look at this budget.

Of the total incoming solar radiation (we’ll call this 100%) about 29% is reflected back into space by clouds, the atmosphere, and Earth’s surface. 23% is absorbed in the atmosphere 48% is absorbed by the Earth’s surface. The Earth’s surface releases 5% of the energy into the atmosphere by convection and 25% by evaporation.

The amount of heat radiated from the atmosphere to the surface (sometimes called “back radiation”) is equivalent to 100 percent of the incoming solar energy. The Earth’s surface responds to the “extra” energy by raising its temperature.

As the temperature of the surface rises, heat is released—equivalent to about 117 percent of incoming solar energy. Some of the heat escapes directly to space, and the rest is transferred to higher and higher levels of the atmosphere, until the energy leaving the top of the atmosphere matches the amount of incoming solar energy.