Two approaches that consider how greenhouse warming might impact the frequency of tropical cyclone (TC) genesis are explored. Results are based on GCM experiments with the q-flux version global climate model of the NASA/Goddard Institute for Space Studies (GISS); one set representing contemporary atmospheric concentrations of CO 2 , contrasting with the second set representing the global climate in double CO 2 equilibrium. July -September means of climate parameters relevant to TC genesis are computed from the simulations and combined to formulate a seasonal genesis parameter (SGP), as suggested in an empirical study by Gray (in Shaw, D.B. (ed.), Meteorology O6er the Tropical Oceans, 1979, pp. 155-218). The spatial distribution of the July -September SGP based on the control simulations is compared with the observed distribution and results using other models. The corresponding spatial distribution of the July-September SGP derived from the double CO 2 simulations, when compared with the control results, projects a 50% increase in the genesis frequency of TC over the western North Atlantic/Gulf of Mexico basin, but 100-200% increases over the North Pacific Ocean. The increases, most of which are attributable to enhanced ocean temperatures, may be exaggerated, suggesting that the original SGP formulation requires tuning or other revisions. For example, it is noted that SGP computed from the NCEP 1982 -1994 re-analysis climatology do not accurately reflect the known spatial distributions of TC genesis frequency. The second approach detects easterly waves over the eastern North Atlantic Ocean by spectral analysis of vorticity and wind component time trends, comparing wave activity in the control and double CO 2 simulations. Results indicate a southward shift in future trajectories of easterly waves over West Africa and significant increases in their average amplitude as they cross the African coast and begin to traverse the Eastern Atlantic along 14ยฐN.