Greenhouse EffectCarbon dioxide and methane are two of a number of so called "greenhouse gases". Greenhouses gases are responsible for the relatively warm temperature of the atmosphere. Without the blanket of greenhouse gases, the Earth would be a frozen ball of ice. The gases of our atmosphere are known as "selective absorbers" of radiant energy. That is, a particular gas absorbs and emits energy well at some wavelengths but not at others. Solar radiation (shortwave) passes through most of the atmospheric gases without being absorbed to a significant extent. However, longwave radiation emitted from the Earth's surface and directed toward the sky is readily absorbed by greenhouse gases. When absorbed, the temperature of the atmosphere increases. Some of this absorbed energy is emitted to space while some is emitted back towards the Earth. This is the basis for the greenhouse effect.
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