Found this on Quora and I think it's interesting - it suggests that LW IR delivers 8.5% of the warming forces.
"The atmosphere loses energy to space as 59% of the 71% of the total solar flux thermalised. That is, at equilibrium the incident radiation absorbed from incident sunlight is emitted in the form of infrared by the surface and the atmosphere. This is 71% of the incident solar flux. It can be seen that the infrared losses to space are largely from the atmosphere at 83% of the total losses to space.
This energy that is emitted back to space from the atmosphere became atmospheric energy largely by latent heat transfer from the surface at (25/59x100)~42%. Secondly direct absorption of incident solar radiation heats the atmosphere at (23/59x100)~39%. Joint third and fourth at (5/59x100)~8.5% is convection and long wave heat transfer from the surface.
Except that latent heat transfer is coupled with convection as ‘moist convection,’ as convection carries the water vapour up to the condensing levels.
Hence the atmosphere is heated as follows;
51% of its energy from moist convection.
39% of its energy from direct absorption of incoming solar radiation
8.5% by long wave heat transfer from the surface to all absorbing species.
(I am aware that the rounded figures fall just short of 100%, but that is the breakdown.)"