Regions along the edges of the tropics host vast populations and ecosystems which are sensitive to climate change. Here we examine the extent of tropical climate land areas in the ERA5 and MERRA-2 reanalyses in high-emission scenarios of 45 models participating in phases 5 and 6 of the Coupled Model Intercomparison Project (CMIP5/6). Based on the definition of tropical climate land areas as regions where the diurnal temperature range exceeds the seasonal temperature range, we find a net reduction of tropical land area with global warming. This change is primarily due to an increased seasonal temperature range, driven by enhanced summer warming. The reduction in tropical land area is consistent with the expansion of the subtropical descending zones and with the expansion of drylands with global warming. However, the particular contributions of dynamic and thermodynamic processes are not clear.