Equations in a Model and Simple Examples
Radiation In = Raditaion Out

We can very simply model the globally averaged temperature. In the simplest sense, the two things that affect the global temperature are

• shortwave radiation coming from the sun
• longwave radiation being emitted by Earth

For a stable climate, we would expect the incoming and outgoing radiation to balance.

For example, if something changes the amount of sunlight reaching Earth, the temperature will increase. This sets off a chain of events - the warmer Earth will emit more radiation, which will gradually cool it, and eventually a balance will again be reached.

Global warming basically comes down to this balance. The amount of outgoing radiation has been decreased by a small amount due to increased amounts of carbon dioxide in the atmosphere. The carbon dioxide molecule is able to trap longwave radiation emitted by the Earth. This is causing globally averaged temperatures to increase. We can understand processes like this that cause the climate to change thanks to the conceptual model of:
"radiation in must = radiation out."
You can learn more about modern climate change here.

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