Tropical cyclones, global climate change and the role of Quaternary studies

The number and types of late Quaternary records of tropical cyclones (TCs) and temperate storms have been increasing globally over the past 10 years. There are now numerous such records for the Atlantic Ocean (USA) and Gulf of Mexico and Caribbean Sea, South Pacific Ocean, and a fewer number from the northwest Pacific and Indian Ocean regions. The most obvious characteristic of these records is that many reveal extended alternating periods of greater and lesser TC activity over the past 6000 years. The length of these phases of relative inactivity and greater activity depends on the chronological resolution of the record, with the coarser-resolution ones displaying multi-century to millennial-scale episodes and the high-resolution records displaying decadal to centennial-scale oscillations. In several instances the likely causes of these alternating periods of TC behaviour have been attributed to different phases of climate when El Ninos and La Ninas dominated or to longer-term variations in sea surface temperatures and possibly solar forcing. The picture emerging from these records is that TC behaviour is not entirely stochastic over the long term and that any simulations of long-term TC behaviour need to account for these climatic influences. Incorporation of these observations, and the many more needed, is important for understanding the future behaviour of TCs. Copyright (C) 2011 John Wiley & Sons, Ltd.