HURRICANE Sandy was a bigger, fiercer and more damaging storm because of human-induced global warming, an analysis produced by Australia's Climate Commission has found.

The burning of fossil fuels had made a material contribution to the atmospheric conditions that bred and sustained the storm, the report said, echoing international studies produced over the past few days.

On Thursday the mayor of New York, Michael Bloomberg, endorsed Barack Obama in the US presidential election, citing the urgency of tackling climate change.

''Our climate is changing,'' Mr Bloomberg wrote in an opinion article. ''And while the increase in extreme weather we have experienced in New York City and around the world may or may not be the result of it, the risk that it might be - given this week's devastation - should compel all elected leaders to take immediate action.''