rm, a primitive atmosphere had developed which also insulated the Earth from the full effects of heat loss and kept the temperature higher. The atmosphere acts much like the glass of a greenhouse and allows much of the incoming shortwave radiation from the sun to strike the Earth, after which much of this energy is transformed into heat. Much of this heat is radiated back into space, but much is not, for it is held in the way heat is by a greenhouse:
The greenhouse effect is thought to be increased as concentrations of water vapor and carbon dioxide rise or to be lessened as they decline. As air warms, its capacity to hold water vapor increases. If atmospheric pollution causes air temperatures to rise, the water-holding capacity of the air will increase, and it is this additional water vapor that would be the primary greenhouse gas of global warming (Bush 321).
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