Most of the work on tropical cyclone genesis has focussed on the local problem, i.e. what causes a particular disturbance to develop into a tropical cyclone. The PIs will focus instead on the global problem which is concerned with the relationship between large-scale climate variables and measures of global or regional tropical activity. The PIs will seek to understand and eventually predict the variations in tropical cyclone genesis frequency as the climate changes, such as in ice age simulations or climate change scenarios. Using atmospheric instability as an index, the PIs will explore the parameter space in a numerical model in order to find a bifurcation point for tropical storm development. The broader impacts of this research on tropical cyclones are found in their relation to weather and climate, and by extension to people and agriculture. The project will involve the participation of a graduate student and a post-doctoral associate.