While so fair the 2009 season has been benign and with the exception of Hurricane Ike 2008 was also relatively free of major category hurricanes in the latest issue of the annual Hazard & Risk Science Review 2009, jointly published by Aon Benfield and PartnerRe the season looks to be extending.

The publication is written by experts at the Aon Benfield UCL Hazard Research Centre, and examines the major research work undertaken and published in the previous year in the four main areas of hazard – atmospheric, geological, hydrological, and climate change related.

This year is has summarised 70 scientific papers published during the past 12 months.

In terms of climate change the report highlights the work of J. P. Kossin, of the University of Wisconsin, writing in the Geophysical Research Letters which examines the timing of Atlantic hurricanes in recent years.

It said he notes that in 2007, storms occurred in both May and December, while the following year, four tropical storms – two of hurricane status – occurred in July. “Similarly, 2005 saw anomalous activity both early and late in the season,” it explains.  “Examining observed historical trends in the annual distribution of North Atlantic tropical storm formation events, and their relationship with tropical Atlantic SST, Kossin detects an apparent tendency towards more common early and late season storms that correlates with higher SST.

“Currently, however, the uncertainties in the correlation are high and the author makes the point that although storm formation dates have been changing over the historical record, the observed trends cannot be used to reliably predict future changes to the season.”

It seems there is more bad news as in addition to the season getting longer; it also seems that Atlantic hurricanes are getting stronger, along with tropical cyclones in other ocean basins. Writing in Nature, J. Elsner of Florida State University, and colleagues, confirm a 30-year trend that shows tropical cyclones in the Atlantic getting progressively stronger, in line with SST rises in the Atlantic region and elsewhere.

“By analysing homogeneous satellite wind-speed data they also show that a comparable trend can be seen in the rest of the tropics,” said the report. “The authors demonstrate a significant overall upward trend for wind-speeds in the most powerful tropical cyclones, which they also recognise in the very strongest storms over each ocean basin, and most noticeably in the North Atlantic.

“As explanation, Elsner and his co-researchers, note that their results are consistent with the simple and straightforward idea that as the oceans warm they have more energy to convert to tropical cyclone wind.”

Professor Bill McGuire, Director of the Aon Benfield UCL Hazard Research Centre, and co-author of the report said: “In this year’s Review, we present a digest of peer-reviewed papers that address critical issues, including hazard characterisation, forecasting and modelling that, together, seek to reduce vulnerability and exposure and diminish disaster risk. Our aim continues to be to improve industry awareness and understanding of natural catastrophes and the processes that drive them, to limit the number of shocks and surprises arising from hazardous events, and to help drive more informed business decisions on a day-to-day basis.”