On the Increasing Intensity of the Strongest Atlantic Hurricanes

• Activity Number: 550
• Type: Invited
• Date/Time: Wednesday, August 3, 2011 : 2:00 PM to 3:50 PM
• Sponsor: Section on Risk Analysis
• Author(s): James Elsner*+ and Thomas Jagger
• Companies: Florida State University and Florida State University
• Keywords: hurricane ; climate change ; quantile regression ; North Atlantic ; trend ; Gulf of Mexico

Abstract

The past three decades have seen a significant upward trend in the intensity of the strongest hurricanes worldwide. Questions remain about this trend especially its relevance to coastal communities in the United States and elsewhere. I focus on observed changes in the intensity of the strongest hurricanes over the North Atlantic basin and on the spatial pattern of these changes. Results show that the upward trend is significantly related to rising sea-surface temperature (SST) after accounting for El Nino. The trend peaks at 16 m/s per C at the 75th percentile with a 90% confidence interval of between 7 and 20 m/s per C. The consequences of increasing intensity of the strongest hurricanes is not confined to the open ocean as nearly 70% of all hurricanes that occur over the basin reach a lifetime maximum intensity west of 60W longitude. The largest intensity increases are occurring over the Gulf of Mexico and the Caribbean Sea, where ocean temperatures are warmest and hurricanes are strongest. Decreases in intensity are noted along most of the United States coastline consistent with a hypothesis that continental aerosols act to decrease hurricane intensity.