All the models have trouble reproducing the tropical lapse rate measured by radiosondes. (opinion-nation.blogspot.ru)
I guess the bigger point is that if the tropical lapse rate changes in such a way as to destabilize the tropical atmosphere a lot (which I am still skeptical of), this says that we are missing something important, the implications of which are hard to predict until we understand it. (gfdl.noaa.gov)
I know very little about tropical dynamics, but have a half - thought question related to the tropical lapse rate: Is there a simple argument for why the relative humidity over land is expected to remain fixed? (gfdl.noaa.gov)