A simple experiment was done by comparing the amount of radiation from the earth in response to warming or cooling over a period of time. (climate-skeptic.com)
You can't assume that there's simple radiation from the earth's surface, at a given temperature. (globalclimatescam.com)
This long period signal is topmost modulated which controls all scale - components, while GHGs is almost the unique factor to directly heat the air by absorbing the longwave radiation from the Earth surface. (judithcurry.com)