Global warming and a concentration of urban developments in “highly exposed” areas will cause insurance companies greater financial pain in coming years, according to the latest Sigma report from Swiss Re.

Despite losses from natural catastrophes and man-made disasters falling in 2006, the global reinsurer has warned the trend can only go up.

In its assessment of natural catastrophes and man-made disasters in 2006, Swiss Re says more than $US48 billion ($61.6 million) in catastrophe-related losses was recorded last year, of which $US15.9 billion ($20.4 billion) was insured. That made 2006 the third-least expensive year for insurers since 1988.

The total for natural catastrophes was $US11.8 billion ($15.15 billion) and man-made disasters around $US4 billion ($5.13 billion), mainly attributable to a “calm hurricane season in the US and the absence of any highly damaging events in Europe”.

About 31,000 lives were lost, mainly in developing countries.

“Going forward, the effects of global warming are also likely to aggravate the loss situation,” the report said. “Climatologists assume that shifting climate zones could lead to weather events that have hitherto been restricted to extreme regions, spreading to other parts of the world.”

Three events ran into the billions: two tornadoes in the US in April and a typhoon in Japan in September.

South-east Asia recorded more than 8000 lives lost or missing from natural disasters in 2006, while Europe’s June heatwave cost 1900 lives at the latest count. Conversely, a cold snap in Eastern Europe took 1333 lives in January.