Hurricanes and Global Climate Dynamics Peter J. Webster School of Earth and Atmospheric Science Georgia Tech During the last two decades, the intensity of hurricanes appears to have increased substantially worldwide. While total number of hurricanes has decreased slightly, the number of the most intense hurricanes (categories 4 and 5) has doubled. These changes are correlated with sea-surface temperature rises throughout the global tropical oceans. While these results raise a number of questions related to the global climate: Why do hurricanes form and what is the role of hurricanes in the heat balance of the planet? How will hurricanes change in a warming world? Hurricane researchers are mostly preoccupied in forecasting the path of storms on an individual basis. Here we attempt to understand hurricanes from the perspective of climate dynamics.