As the 2008 hurricane season winds down, you might be wondering whether you’ve seen more images of families huddled on rooftops or assessing sodden piles of belongings this year than you did, say, two decades ago. The answer is yes.

According to statisticians such as insurer Munich Re and the Centre for Research on the Epidemiology of Disasters, numbers of “extreme events” such as this summer’s storms, hurricane Katrina in 2005 and the 2004 tsunami in south-east Asia have quadrupled since the 1970s as a result of climate change, increased settlement in risky areas and urbanisation in the developing world. Combinations of disasters – earthquakes followed by fires or windstorms and water surges – are typical, with the after-effects often wreaking as much havoc as the main events.