The United States is vulnerable to the devastating impacts of hurricanes. The confluence of more to lose and a greater risk of loss makes the problem acute. Our mission is to improve understanding and prediction of the hurricane risk in the face of climate variability and climate change. The mission is conducted through research, education, and service. Work is supported by Florida State University, the National Science Foundation, and the Risk Prediction Initiative.

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Global Warming, Atlantic Hurricanes, and Insured Losses

Increases in Atlantic hurricane activity during the past decade are related to increases in tropical Atlantic warmth. A debate concerns the attribution of these increases with some suggesting a natural atmospheric/oceanic cycle called the Atlantic Multidecadal Oscillation (AMO) and others suggesting climate change. Leading atmospheric scientists in academia and government are found on both sides of this issue. The large correlation between late summer/early fall Atlantic sea surface temperature (SST) and global near-surface air temperature together with lagged values of global temperature predicting SST but not the other way around argues in favor of the climate change hypothesis. However the positive influence of climate change on Atlantic hurricane activity is limited to the connection with Atlantic SST possibly as a consequence of increased atmospheric thermodynamic stability and/or wind shear from greater warmth.

The return period of a Katrina-like hurricane is 21 years for the Gulf coast of the United States (Texas through Alabama) and 14 years for the entire coast. Hurricane Katrina might be a harbinger of things to come in a warmer world as the observed and modeled consequence of climate change on hurricane intensity appears to start at Katrina's observed near-coastal intensity of 71 m/s. The annual probabilities for hurricanes weaker than Katrina do not change between globally warm and globally cool years. However, for hurricanes stronger than Katrina the increase in the 100-year return intensity from cold to warm years is 11%.

Coastal hurricanes generate huge financial losses for the insurance industry. The relative infrequency of severe coastal hurricanes implies that empirical probability estimates of the next big loss will be unreliable. Hurricane climate science has advanced to the point where hurricane activity can be predicted several months and even several years in advance with some skill using probability models. Similar models can be used to forecast the expected and maximum annual aggregated insured loss prior to the start of the hurricane season. From year to year the effect of climate change on insured losses will be minor relative to El Niño, the North Atlantic Oscillation, and random SST fluctuations, but averaged over several years the effect could be significant.

Hurricane Climate

Hurricane climate is the study of hurricanes that includes the role climate factors play in modulating seasonal, annual, and decadal hurricane activity. Hurricane climatology is the statistics (e.g., mean number of hurricanes, maximum intensity, etc.) of past hurricane activity over some reference time period. The role climate factors play in modulating hurricane activity are examined using empirical, statistical, and dynamical models. For hurricanes occurring over the North Atlantic, climate factors include El Niño, the North Atlantic Oscillation (NAO), and the Atlantic sea-surface temperature. Hurricane climate also includes the role global warming might have on hurricane activity.

Program Managers: K. Kemper (FSU), J. Fein (U.S. NSF), R. Murnane (RPI). Views expressed on this website are ours and do not necessarily reflect those of U.S. NSF, RPI, or FSU.