Boundary layer turbulence plays a central role in determining the strength of the overall atmospheric circulation by affecting the intensity of exchange of heat, mass, and momentum at the Earth's surface. It is often parameterized using the bulk formula, in which the von-Karman parameter plays a critical role. Here we conducted a range of sensitivity simulations with an atmospheric general circulation model in which we modified the strength of boundary layer turbulence by varying the von-Karman parameter. These simulations show that the maximum of entropy production associated with boundary layer dissipation is consistent with the observed value of the von-Karman parameter of 0.4 and maximizes the planetary rate of entropy production with the global radiative temperature being close to its minimum value. Additional sensitivity simulations were conducted with an increased concentration of atmospheric carbon dioxide, which affects the relative radiative forcing of tropical vs. polar regions. We find that the global climate sensitivity is more-or-less independent of the assumed strength of boundary layer turbulence in our idealized setup. The difference in climate sensitivities of tropical and polar regions is at a minimum at a climatic state of MEP.