The upward trend in economic losses from hurricanes in the US cannot be explained by the commonly invoked increases in vulnerability and exposure, concludes a study published online in Nature Geoscience. The rise in losses is consistent with an influence of global warming on the number and intensity of hurricanes, an influence which may have accounted for 2-12% of the US hurricane losses in 2005.

Economic losses from natural disasters, and in particular hurricanes, have risen over the past decades. However, whether these increases are caused by socioeconomic factors, such as increases in wealth and population in coastal regions that are vulnerable to hurricanes, or by an increase in extreme weather events, has been contentious.

Using a statistical approach that minimizes the risk of introducing artificial trends, Francisco Estrada and co-authors estimate the contribution of socioeconomic factors to the observed rise in economic losses from hurricanes in the US between 1990 and 2005. They find that part of the trend cannot be explained by commonly used socioeconomic factors, but is consistent with an increase in the number and intensity of loss-generating cyclones that hit the US, possibly as a result of global warming. The authors estimate that US$2-14 billion of US hurricane losses incurred in 2005 may be attributable to climate change.

In an accompanying News & Views article, Stephane Hallegatte writes that the study “serves to re-open the debate on the role of climate change in hurricane losses that had been largely discounted.”