Clustered hurricanes reduce impact on ecosystems

EurekAlert: New research has found that hurricane activity is 'clustered' rather than random, which has important long-term implications for coastal ecosystems and human population. The research was carried out by Professor Peter Mumby from The University of Queensland Global Change Institute and School of Biological Sciences, Professor David Stephenson and Dr Renato Vitolo (Willis Research Fellow) at the University of Exeter's Exeter Climate Systems research centre.

Tropical cyclones and hurricanes have a massive economic, social and ecological impact, and models of their occurrence influence many planning activities from setting insurance premiums to conservation planning. Understanding how the frequency of hurricanes varies is important for the people that experience them and the ecosystems that are impacted by hurricanes.

...Short intense periods of hurricanes followed by relatively long quiet periods, were found around the Caribbean Sea and the clustering was particularly strong in Florida, the Bahamas, Belize, Honduras, Haiti and Jamaica. Modelling of corals reefs of the Caribbean found that clustered hurricanes are 'better' for coral reef health than random hurricane events as the first hurricane always causes a lot of damage but then those storms that follow in quick succession don't add much additional damage as most of the fragile corals were removed by the first storm.

The following prolonged period without hurricanes allows the corals to recover and then remain in a reasonable state prior to being hit by the next series of storms.

...Clustering of storms and other weather events is a global phenomenon that needs to be better quantified statistically in risk assessments' says study author Professor David Stephenson. 'We didn't at first expect clustering to have advantages but this study has clearly shown that clustering can help by giving ecosystems more time to recover from natural catastrophes' Professor Stephenson adds, 'This research also has wider implications for other systems such as the dynamics and viability of insurance companies and the provision of reinsurance protection.'...

Hurricane Ike approaching Cuba in September, 2008. Shot by NASA