The tropospheric lapse rate is maintained mostly by convective
transports of heat upwards, in thunderstorms and thunderstorm complexes, including mesoscale disturbances, various waves and tropical storms, while radiative processes serve to cool the troposphere.
All that is needed is to add
heat carried
upwards past the denser atmosphere (and most CO2) by convection and the latent
heat from water changing state (the majority
of heat transport to the tropopause), the albedo effects
of clouds, the inability
of long wave «downwelling» (the blue balls) to warm water that makes up 2 / 3rds
of the Earth's surface, and that due to huge differences in enthalpy dry air takes far less energy to warm than humid air so temperature is not a measure
of atmospheric
heat content.