The Norwegian Refugee Council (NRC) told the United Nations yesterday that natural disasters displaced 22 million people last year and an average of 27m a year since 2008.

Such displacement has doubled in the past 40 years, as the world population grew and rapidly urbanised.

“Natural disasters, floods, hurricanes and earthquakes have displaced many more people than wars and conflicts,” said NRC secretary-general Jan Egeland.

A major cause of the increase is massive migration to big cities in the developing world, which makes them vulnerable to natural disasters aggravated by climate change, the council said.

“Urbanisation has happened in a bad way, in very disaster-prone areas,” Mr Egeland said. “The slums of the big cities … become traps.”