Editor's Summary
7 June 2007
Hurricane seasons 'normal'
The frequency of major hurricanes over the Atlantic Ocean has increased significantly since 1995, but it is still not clear whether this is due to global warming or natural variability. One way to address this question is to consider changes in hurricane frequency in the past, but reliable observations of Atlantic hurricane activity only cover a few decades. Nyberg et al. use proxy records from corals and a marine sediment core that appear to reflect changes in the two main parameters that influence hurricane activity — vertical wind shear and sea surface temperature — to reconstruct the frequency of major hurricanes over the Atlantic since 1730. The results indicate that the frequency was anomalously low during the 1970s and 1980s compared with the past 270 years, and that the phase of increased hurricane frequency since 1995 represents a recovery to 'normal' hurricane activity. These trends appear to be related to wind shear, but what caused this parameter to change remains uncertain.
News and Views: Climatology: Tempests in time
The frequency of severe hurricanes in the North Atlantic has increased during the past decade. Scrutiny of the prehistoric record left by such storms helps to assess the factors contributing to hurricane activity.
James B. Elsner
doi:10.1038/447647a
Letter: Low Atlantic hurricane activity in the 1970s and 1980s compared to the past 270 years
Johan Nyberg, Björn A. Malmgren, Amos Winter, Mark R. Jury, K. Halimeda Kilbourne & Terrence M. Quinn
doi:10.1038/nature05895
First paragraph | Full Text | PDF (963K) | Supplementary information
