The additional greenhouse effect due to an increase in the concentration of greenhouse gases. Because of the complexity of the feedback processes within the climate system, the enhanced greenhouse effect is usually referred to in terms of the radiative forcing that results at the tropopause, after the stratosphere has come into a new radiative equilibrium. For example, thus defined, the enhanced greenhouse effect due to an effective doubling of carbon dioxide concentration from its preindustrial baseline is about 4 W m−2. Note the difference in meaning from the greenhouse effect, which refers to the entire natural process and which results in a climatological average counterradiation of about 330 W m−2 to the surface. A comparable value for the enhanced greenhouse effect at the surface will only be obtained once the new equilibrium temperature of the surface is known, since they are strongly interrelated.