Modeled Impact of Anthropogenic Warming on the Frequency of Intense Atlantic Hurricanes

Abstract

Stormy Weather One of the most active questions about the effects of global warming is whether, and how, it might affect the frequency and the strength of hurricanes. Some studies have suggested that warming will bring fewer, and less energetic, hurricanes, while others have claimed that we can expect more intense storms. Bender et al. (p. 454 ; see the news story by Kerr ) explore the influence of global warming on hurricane dynamics over the Atlantic Ocean with a state-of-the-art hurricane prediction model. The model predicts that the annual total number of hurricanes in the 21st century will be less than now, but also that the number of the most intense storms per year will increase. The largest increase of the most intense hurricane frequency is predicted in the western Atlantic, which suggests that Hispaniola, the Bahamas, and the Southeast coast of the United States could be at greater risk.

Recent intense hurricane response to global climate change

“…Oouchi et al (2006) found a general increase in the most intense hurricanes and a decrease in weaker ones for a time-slice simulation forced by current and future surface temperatures and greenhouse gases; similar findings were made by Bengtsson et al (2007). Bender et al (2010) examined the potential climate changes in North Atlantic hurricanes using two versions of the GFDL hurricane model as a downscaling tool applied to tropical cyclones generated in the GFDL climate model. The technique for the climate simulation was to use current climate boundary conditions (horizontal and surface) plus a constant change in thermodynamic parameters (Knutson et al 2007).…”

“…The technique for the climate simulation was to use current climate boundary conditions (horizontal and surface) plus a constant change in thermodynamic parameters (Knutson et al 2007). Bender et al (2010) found that for each°C of global warming the proportion of Cat 4-5 hurricanes increased by *11 % and the proportion of Cat 1-2 hurricanes decreased by *7 %. Done et al (2012) applied Weibull and Generalized Pareto distributions to assess the expected changes in future North Atlantic hurricane extremes based on changes to the mean and variance of the truncated distribution predicted by the NCAR Nested Regional Climate Model (Done et al 2012).…”

“…We further compare the observed changes to recent climate simulations with the dynamical downscaling results of Bender et al (2010), Done et al (2012), and Wu and Zhao (2012).…”

“…The increases are substantial, approaching a doubling in frequency of Cat 4 and 5 hurricanes [based on the Saffir-Simpson classification, Simpson and Rielh (1981)] for each°C in global warming (Bender et al 2010;IPCC 2012;Done et al 2012). IPCC (2007) also concluded that the current 'warming of the climate system is unequivocal'.…”

A decadally-resolved paleohurricane record archived in the late Holocene sediments of a Florida sinkhole

“…Changes in the intensity distribution of hurricanes occurring in concert with changes in storm frequency could cause the frequency of storm deposits in sites with different flooding susceptibilities to diverge. Numerical modeling of late 21 st century hurricane climatology has suggested that declines in overall Atlantic hurricane frequency could occur simultaneously with a broadening of the intensity distribution of hurricanes leading to fewer but more intense storms , Gualdi et al 2008, Knutson et al 2008, Zhao et al 2009, Bender et al 2010). However, recent warming and increased hurricane frequency in the Atlantic has purportedly been accompanied by a disproportionate increase in the occurrence of intense hurricanes (Emanuel 2005, Webster et al 2005, Hoyos et al 2006.…”