Greenhouse effect.

We see the decrease in black body temperature measured in the IR spectrum We see the decrease in temperature due to an increased amount of heat being retained at the surface of the globe.
At every GHG spectral line we see the drop in black body temperature.
How does the greenhouse effect work?
Visible and UV light from the sun hits the earth, some gets reflected most hits the surface and warms it and the surface emits infrared. As the IR photon heads out to space it might be absorbed by a molecule of a GHG (any molecule with three or more atoms, hence CO2, H2O, O3, N2O, CH4 etc) exciting that molecule: it spins and vibrates more rapidly. It cannot hang on the photon for long so emits the photon. It could re-emit it downwards as likely as it re-emits it upwards. The photon could be absorbed–re-emitted by more than one GHG molecule.
Any IR that returns to the surface warms it: the molecules, water or rock hit by the photon vibrate more quickly.
The measurement of IR on the surface in Alaska and Montana showed that there was more IR reaching the surface, more radiative forcing, when the concentration of CO2 was highest.