There is a warming of the surface by infra-red active gases, the so-called greenhouse gases, but that effect was maximized at lower concentrations of those gases than we now have.Increases in those gases now cause small decreases in surface and general tropospheric temperatures.This is because the mean free length for infra-red absorption by these gases is now too short for them to move the upper troposphere radiative equilibrium altitude to higher altitudes in the dense troposphere.