yep that is one theory.... it is not inconsistent with what i have been saying on thread.
however, how much of the sun's energy is shielded by co2 is a big question.
the "science" of the energy budget and climate sensitivity is in flux... so to speak.
here is one theory....
http://hockeyschtick.blogspot.com/2010/06/physicist-cooling-effect-of-co2-is-100x.html
"the cooling effect due to keeping incoming solar IR radiation away from the surface is about 100 times the re-heating effect proclaimed by greenhouse gas alarmists"
"Finally, the IR radiation is not absorbed by nitrogen, oxygen, and argon gases which make up 99% of the atmosphere, so a large fraction of it directly warms the Earth's surface. Some, is absorbed by the dominant greenhouse gas, water vapor, and small amounts are absorbed by carbon dioxide and other greenhouse gases. The incoming IR radiation absorbed in the atmosphere is less effective in warming the Earth's surface than is that which is absorbed by the Earth's surface directly. This is because some this energy absorbed in the atmosphere then is radiated again in the form of IR radiation, but now half or more of that is directed out to space. In other words, more water vapor and CO2 in the atmosphere results in a less effective warming of the surface than does less of these gases with respect to the incoming IR energy from the sun. The greenhouse gases have a cooling effect on the original solar radiance spectrum for the 45% of the solar energy in the form of IR.
In each case, whether UV, visible light, or IR, not all of the radiation of that form striking the Earth's surface is absorbed. Some fraction is reflected and the fraction is very dependent on whether the ground is covered with snow, plowed earth, grasses, forests, crops, black top, or water. There are two real ways that man does have some effect on the Earth's temperature. He changes the surface of the earth over a fraction of the 30% of its surface which is land. He also converts fossil and biomass fuels into heat. Compared to the overall natural effects, these man-made effects are small, yet they are probably large compared to the effect of his adding CO2 and methane to the atmosphere."