Earth's
atmosphere allows some frequencies of light to pass through more often than others. When
solar radiation is absorbed by the
land or
ocean, they increase in temperature. Eventually they will re
radiate this energy, but most of the
radiation will be of a longer wavelength, and the
atmosphere will absorb much of this reradiated energy rather than allowing it to pass out into outer space. This is the
greenhouse effect.
This effect is increasing - partly as a result of gases emitted into the atmosphere by human beings, although scientists disagree how much. The resulting increase in temperature or global warming is also referred to as the greenhouse effect.