A UN envoy said Monday that the economic cost of disasters in 2011 was the highest in history — with a price tag of at least US$380 billion, mainly due to earthquakes in Japan and New Zealand.

Margareta Wahlstr?m, Assistant Secretary-General for Disaster Risk Reduction. [UN/JC McIlwaine]

Margareta Wahlstrom, the Secretary-General's special representative for disaster risk reduction, said the figure was two-thirds higher than the previous record in 2005. In addition to the earthquakes, major floods in Thailand and other countries caused extensive damage.

"We say today that 50 percent of the world's population is exposed to disaster risks because they live in highly vulnerable areas," Wahlstrom said. Despite the rising costs, she said, deaths from disasters are proportionally declining because countries are getting much better at instituting early warning systems and preparedness measures.

Wahlstrom said the risk of disasters is increasing globally because of climate change, the depletion of natural resources, poor land use and worsening environmental problems.

For example, by 2050 the world will need 50 percent more food, 45 percent more energy and 30 percent more water for a growing population — and these resources are already under threat and are triggers of disaster.

Wahlstrom said every plan to improve development in a country must include measures to deal with the impact of climate change and natural disasters.