Possible Changes in Tropical Cyclone Frequency and Intensity due to Global Warming

Abstract

 This paper reviews assessments of possible changes in tropical cyclone frequency and intensity due to global warming, based on climate change projection experiments using atmospheric general circulation models (AGCMs). Recent experiments with relatively high-resolution (mesh size of about 100 km or less) models consistently indicate that the global frequency of tropical cyclones is likely to decrease due to global warming. In contrast to the global frequency, the regional tropical cyclone frequencies projected by various models significantly differ from each other. On the other hand, high-resolution (mesh size of about 50 km or less) models consistently indicate that future tropical cyclone intensity (wind and precipitation) is likely to increase. As a result, the number of intense tropical cyclones may increase, even if the total number of tropical cyclones decreases. The reduction in tropical cyclone frequency and the increase in tropical cyclone intensity are likely to be qualitative. However, it should be noted that there are enormous quantitative uncertainties in these projections of possible changes in tropical cyclone frequency and intensity, particularly among the regional changes. The large uncertainties in the projections of regional changes in tropical cyclone frequency and intensity make it difficult to use the information effectively in planning measures to mitigate the future wind disaster risk associated with tropical cyclones in particular regions. Reducing the uncertainty in climate change projections, particularly regarding regional changes, is the most demanding task for climate change research.