Hurricanes and Global Warming

347 MARCH 2008 AMERICAN METEOROLOGICAL SOCIETY | T ropical cyclones account for the majority of natural catastrophic losses in the developed world and, next to floods, are the leading cause of death and injury among natural disasters affecting developing countries (UNDP/BCPR 2004). It is thus of some interest to understand how their behavior is affected by climate change, whether natural or anthropogenic. A range of techniques has been brought to bear on this question. The most straightforward approach is to quantify the response of tropical cyclone activity to past climate change using historical climate and storm records, but this approach is limited by the relatively short length of tropical storm records. In the North Atlantic region, dense ship tracks, islands, and the relatively small size of the basin have led to the creation of an official archive extending back to 1851 (Jarvinen et al. 1984; Landsea et al. 2004), but the detection rate prior to the satellite era remains controversial (Landsea 2007). Routine aircraft reconnaissance of tropical cyclones began shortly after WWII in the North Atlantic and western North Pacific regions, and while it continues to this day over the Atlantic, it was terminated in 1987 over the western North Pacific. These missions undoubtedly improved the detection rate, though it is possible that some storms were still missed. In the active tropical cyclone belts of the eastern North Pacific, and in virtually all of the Southern Hemisphere, high detection rates were not achieved until about 1970, when satellites covered a sufficiently high portion of the globe. This relatively short and flawed record of tropical cyclone activity has nevertheless led to the detection of significant climatic inf luences on tropical cyclone activity, most prominently, the influence of El Niño–Southern Oscillation (ENSO) on storms in the North Atlantic (Gray 1984; Bove et al. 1998; Pielke and Landsea 1999; Elsner et al. 2001) and western North Pacific (Chan 1985). Variations on time scales HURRICANES AND GLOBAL WARMING Results from Downscaling IPCC AR4 Simulations