Scientific Colloquium
April 23, 2004

The problem of global warming raises the issue of whether tropical cyclone
frequency and/or intensity might change in the near future and leads us to
ask how the climate state controls tropical cyclone activity in general. In
this talk, I will present new results that strongly suggest that both the
frequency and intensity of tropical cyclones are strongly sensitive to
tropical climate. I will also present evidence that the ocean's thermohaline
circulation is sensitive to global tropical cyclone activity and argue that
the coupling of these two sensitivities results in an efficient tropical
thermostat that keeps tropical temperatures very stable over geologic time.