Recent hurricane history provides diverging interpretations on future of hurricane activity

Washington, Nov 1 : A new study has explored the relationship between sea surface temperature (SST) and seasonal hurricane activity, showing how differing interpretations of the observational record can imply vastly different futures for Atlantic hurricane activity due to global warming.

The study was done by scientists Gabriel A. Vecchi, Kyle L. Swanson, and, Brian J. Soden, who teamed up to study hurricane data observed over more than 50 years.

The scientists came up with two interpretations, which arose from assumptions of whether it is the local SST in the Atlantic in isolation, or whether it is the SST in the Atlantic 'relative' to the rest of the tropics, that drives variations in Atlantic hurricane activity.

If the local SST hypothesis is to be believed, then by 2100, the lower bound on Atlantic hurricane activity is comparable to that of 2005, when four major hurricanes struck the continental United States, causing more than 100 billion dollars in damage.

The upper bound exceeds 2005 levels by more than a factor of two.

The second interpretation, known as the relative SST hypothesis, envisions a future similar to the recent past, with periods of higher and lower hurricane activity relative to present-day conditions due to natural climate variability, but with little long-term trend.

The statistical relationship between either interpretation of the SST/hurricane activity link is ambiguous over the period 1946-2007, but they imply fundamentally different projections for the future and interpretations of the past.

The team further argues that the consistency between theory, numerical models, and historical observations offers compelling evidence that the 'relative' SST hypothesis is more accurate and provides a better framework for projections of future changes in hurricane activity.

ANI