Of course it is radiation that removes heat from the Earth, since heat can not be removed to space by convection or conduction (since there is no matter in space to conduct to). The warm Earth radiates in all directions, but the little of the radiation that heads outward to space gets reabsorbed by the atmosphere before it escapes.
“The warm Earth radiates in all directions, but the little of the radiation that heads outward to space gets reabsorbed by the atmosphere before it escapes.”
Not according to the study using latest satellite-based data conducted by the learned MIT professor.