Most of the absorption of the solar radiation is by the surface directly illuminated in line-of-sight with the sun. In comparison to the infrared-emitting surface area, this is reasonably consistent with the general models used by the catastrophic man-made global warming hypothesis.
The heat-emitting surface area is actually larger than is the absorbing, line-of-sight surface area. This is especially the case in land areas. A rough, rocky surface has a much higher surface area than does the surface of the perfectly smooth sphere used in the models. A vegetated area has heat emission from the ground and from every part of every plant on that surface. The stems and trunks emit heat. Both sides of every leaf emit heat. Let us say that the 71% of the Earth's surface which is water has a surface area about equal to that of the round, smooth surface as a simple base for further discussion, though even its surface area is slightly larger. This leaves 29% of the surface and those areas with vegetation may have a surface area which is 2 or 3 times the surface area of the smooth sphere in a given bordered area in 2-dimensions as viewed from space. Desert and arctic areas may only have an area 1.3 times as large. Every surface mineral particle in the desert with an air-exposed area will have a surface area much greater than the portion of the surface of a sphere covering the same periphery.
It is not at all unlikely that the average land area whose solar absorbing surface area is A, would have a heat-emitting surface area of about 1.6 A. Thus, the heat-emitting area including the 71% of the Earth's surface which is water and the nominal 29% which is land could readily be: