Global Warming Effects on U.S. Hurricane Damage

While many studies of the effects of global warming on hurricanes predict an increase in various metrics of Atlantic basin-wide activity, it is less clear that this signal will emerge from background noise in measures of hurricane damage, which depend largely on rare, high-intensity landfalling events and are thus highly volatile comparedtobasin-widestormmetrics.Usingarecentlydevelopedhurricanesynthesizerdrivenbylarge-scale meteorological variables derived from global climate models, 1000 artificial 100-yr time series of Atlantic hurricanes that make landfall along the U.S. Gulf and East Coasts are generated for four climate models and for current climate conditions as well as for the warmer climate of 100 yr hence under the Intergovernmental Panel on Climate Change (IPCC) emissions scenario A1b. These synthetic hurricanes damage a portfolio of insured property according to an aggregate wind-damage function; damage from flooding is not considered here. Assumingthat the hurricane climate changes linearly with time, a 1000-member ensemble of time series of propertydamagewas created.Three of thefour climatemodels usedproduce increasing damagewith time, with the global warming signal emerging on time scales of 40, 113, and 170 yr, respectively. It is pointed out, however, that probabilities of damage increase significantly well before such emergence time scales and it is shownthatprobabilitydensitydistributionsofaggregatedamagebecomeappreciablyseparatedfromthoseof the control climateon time scales as shortas 25 yr. For the fourthclimatemodel, damagesdecreasewith time, but the signal is weak.