|Joplin, Missouri after a devastating tornado in 2011 [GALLO/GETTY]
The issue of climate change is often talked about simply in terms of the predicted rise in temperature. It is generally acknowledged that a global increase in temperature before the end of the century above two degrees Celsius would be catastrophic.
Yet long before the end of the century, even the small changes in temperatures we have seen over the last 20 to 30 years are believed to be having significant impacts on the climate.
Whilst no one is claiming that the deadly tornado season of 2011 in the United States was solely the result of climate change, it is likely that increasing water temperatures in the Gulf of Mexico spawn greater numbers of thunderstorms which feed off the warm waters. Wherever there are thunderstorms there is greater risk of tornadoes.
On this basis, Accuweather.com predict that the 2012 tornado season is likely to be ‘above average’.
The 2011 season caused almost $30 billion in damages and killed more than 550 people. The death toll was the highest on record partly because the strongest tornadoes hit populated areas such as Joplin, Missouri and Birmingham, Alabama rather than the open plains of Kansas, Oklahoma and Texas.
This eastward displacement of tornadoes from the usual ‘Tornado Alley’ is thought to be the result of La Nina, which, in turn, may be influenced by global warming.
In a separate study at Princeton University and Massachusetts Institute of Technology, researchers predict that storm surges – walls of water propelled by hurricanes and other major storm systems – are likely to increase. Flooding events which, in the past, occurred once in a hundred years could now happen every 3 to 20 years.
Such statistical re-evaluations of major flooding events is likely to have an impact for the insurance industry which will have to reconsider its risks and premiums.