Natural catastrophes caused $US65 billion ($62.4 billion) in insured losses last year, according to Swiss Re and Munich Re.

Overall economic losses were at least $US140 billion ($134.5 billion), Swiss Re says, while Munich Re put the figure at $US160 billion ($153.7 billion).

Some 90% of insured losses were attributable to the US, with the highest costs caused by Superstorm Sandy – estimated at up to $US25 billion ($24 billion).

Even though the hurricane itself was comparatively weak, tides and interference with associated weather patterns increased its impact, Swiss Re says.

The insured losses are above the 10-year average of $US50 billion ($48 billion) but lower than the $US120 billion ($115 billion) in 2011.

Munich Re board member Torsten Jeworrek says greater loss-prevention efforts are needed.

“It would certainly be possible to better protect conurbations such as New York from the effects of storm surges,” he said. “Such action would make economic sense.”

Insured crop losses in the US were about $US15-17 billion ($14.4-16.3 billion), with almost half the country’s arable acreage affected by drought, Munich Re says. Until November, the year had been the warmest on record.

Other costly insured catastrophes included severe storms, tornadoes and the “derecho” storms in the US.