A natural catastrophes study by reinsurer Munich Re has found that Tokyo is the most vulnerable city on earth, in terms of natural catastrophes. The study, which takes into account natural disasters such as floods, earthquakes, bushfires and volcanoes, also looked at different building types, population and the preparedness of cities.

And according to the latest Sigma report published by Swiss Re, natural and man-made disasters cost general insurers $US13.5 billion last year. Australian natural disaster losses alone accounted for $380 million, which was a rise of about $1.8 million compared to 2001.

Metropolitan “mega-cities” have been dubbed as the most risky, with San Francisco, Los Angeles, Miami, New York and Osaka following Tokyo on the risk list.

UN statistics show that more than 50% of the world’s population live in urban areas. This compares to about 30% in 1950. Munich Re estimates that more than 11,000 people were killed in natural catastrophes last year, and the number of loss events was 700, which is well above the long-term average of 650.