Recent advances in the emerging field of paleotempestology

Abstract

Roughly 35% of the world's 7.4 billion people are in the path of tropical cyclones, and coastal populations are expected to increase in the coming century. To understand the future damage that tropical cyclones could impose on an ever-growing coastal population, it is critically important to better understand the relationships between tropical cyclones and climate. Large-scale features of the climate system have been shown to affect tropical cyclone activity, for example, the El Niño Southern Oscillation (ENSO) has been shown to influence tropical cyclone frequency in all oceanic basins on seasonal, yearly, and decadal timescales. However, the relatively short observational record (<160 years) is inadequate for identifying the climatic influences on tropical cyclones over centennial to millennial timescales. Paleotempestology, a relatively new science, helps to resolve this issue by extending the instrumental record back several thousands of years. Over the past two decades, the number of paleotempestology records has increased substantially for sites along the Northwest Atlantic Ocean, Gulf of Mexico and Caribbean Sea, the South Pacific Ocean, and the Northwest Pacific and Indian Ocean regions. The most obvious characteristic of these records is that they reveal extended alternating periods of either greater or lesser tropical cyclone activity over centennial and millennial timescales. In these studies, researchers have shown that large-scale climatic features such as ENSO, sea surface temperatures (SSTs), the latitudinal position of the intertropical convergence zone (ITCZ), and the North Atlantic Oscillation (NAO) are likely driving the alternating long-term behavior of tropical cyclones in global oceanic basins. This review paper will focus on recent paleotempestology studies from multiple global sites and endeavor to synthesize the results and interpretations.