The world must prepare now for the serious impact climate change will have on health, from a jump in waterborne diseases to heart attacks and heat-wave deaths, the World Health Organization said yesterday.

"We need to wake up," warned Alex Hildebrand, an environmental health adviser from WHO's regional office in New Delhi. "We need to take this much more seriously."

The global health body was hosting a three-day workshop during a massive climate conference on Bali island, where delegates from nearly 190 nations are seeking ways to head off dour scientific predictions.