Tropical cyclones and coastal inundation under enhanced greenhouse conditions

The behavior of tropical cyclones under enhanced greenhouse conditions has been the subject of considerable speculation Typical spatial scales of these cyclones are on the order of tens to hundreds of kilometers. Therefore they cannot be simulated in global climate models with resolutions of several hundred kilometers. Thus speculation has been largely based on extrapolation from their present observed distribution, and on simple parametric relationships. However, the conditions under which tropical cyclones from, the intensities they reach, and their usual paths depend on a number of dynamic and thermodynamic factors that may change in complex ways with changing climate. Recent studies using finer resolution global and regional climate models, sensitivity studies that model individual cyclones, and parametric studies have been reviewed. These suggest that the future behavior of tropical cyclones remains an open question with changes of either sign possible in numbers and intensities. The paper also describes the combined effect on coastal inundation of mean sea level rise and changes in storm surges due to tropical and extratropical cyclones. Impact studies highlight the importance of taking both these factors into account and the highly site-specific nature of the problem.