We have covered many papers in the recent scientific literature that do not support the hypothesis that global warming has led, or will lead, to large changes in the intensity of tropical cyclones (see here and here and here). Michaels et al. (2006), Pielke Jr. et al. (2006), and Hoyos et al. (2006), all present evidence that the tropical cyclone regime, at least in the Atlantic basin, during the past 20-30 years, is a complex combination of the interactions of several different environmental factors that include sea surface temperatures (SST), vertical wind shear, and atmospheric stability, among others. The variations and trends of these parameters are often not what has been projected by models for anthropogenerated global warming. The climate models also project far more modest changes in hurricane intensity than are being observed. This is further evidence that factors other than those directly related to anthropogenic climate change are influencing observed trends and variations in tropical cyclones. These other factors include cyclical, or quasi-cyclical, oscillations as well as possible observational biases in the record resulting from changing technology and observing practices that have evolved over the past century or so.
These results do not support the hypotheses of Emanuel (2005) and Webster et al. (2005) that link large changes in the intensity of tropical cyclones primarily to increased SST caused by global warming