Hurricanes, floods show risks of climate change: UN

In India, three million people have been displaced from their homes and at least 90 killed by floods in India's eastern state of Bihar, officials say, after the Kosi river burst a dam in Nepal. The floods are the worst in Bihar in 50 years.

In addition to the human suffering "we have an economic escalation from damage from natural disasters," Steiner said.

Insurers Munich Re said that first-half losses from natural catastrophes totalled about $50 billion -- many linked to a rising number of extreme weather events.

The main exception was $20 billion from China's Sichuan earthquake that killed at least 70,000 people. For all of 2007, losses totalled $82 billion, it said in a July report.

"Growing populations and infrastructure means that we are going to face more and more events of this nature," Steiner said.

Katrina was the costliest hurricane in U.S. history, killing some 1,500 people and causing over $80 billion in damage.

"Natural disasters are increasingly becoming a major risk to our economies," Steiner said. "Our societies cannot afford this, our insurance industry cannot afford an escalation of risks."

(Editing by Robert Hart)