The foundation of the greenhouse theory is that 'greenhouse' gases absorb infrared radiation from the earth and then 'back-radiate' this energy to the earth to cause global warming. Several prior posts have illustrated that the concepts of greenhouse gas 'back-radiation,' 'heat-trapping,' 'heat capture,' and 'radiative forcing' are essentially all referring to the same unphysical, fundamental error of the greenhouse theory that cannot be found in textbooks of physics.