"In the developing countries it's critical we think of combining mitigation measures with adaptation measures," said Rajendra Pachauri, head of the UN Intergovernmental Panel on Climate Change that shared the 2007 Nobel Peace Prize with former US Vice President Al Gore.

"We know extremes of temperatures are going to go up, now we have to adapt to them," he said at a climate panel at Columbia University late on Wednesday.

The United Nations agreed to start an adaptation fund for poor countries last month at climate talks in Bali, Indonesia. It comprises only about US$36 million, but might rise to as much as US$5 billion a year by 2030 if investments in green technology in developing countries increase.

"There is a global imperative for us to find means by which the worst afflicted regions of the world can be protected," said Pachauri, adding that the developed world was responsible for most of the planet-warming gases already in the atmosphere.

Much of the global effort to fight climate change has concentrated on trying to cut greenhouse gas emissions through technologies like solar, wind and geothermal power.

That strategy should be combined with adaptations like restoring mangrove forests, which can protect coastal dwellers from the threat of rising seas, he said.

WORKING HAND IN HAND

The IPCC's fourth assessment released last year was the first of the group's reports to say adaptation can complement mitigation to fight climate change.

"Both are required, neither is sufficient on its own," Cynthia Rosenzweig, a NASA scientist and one of assessment's lead authors, told the panel.

Many of the developing country adaptations involve water because climate change is likely to increase the frequency of droughts and floods, Pachauri said. Training health care workers to quickly rehydrate large numbers of people could help reduce casualties during droughts.

The Netherlands has built dykes and other systems that may help protect it from the threat of rising seas. But developing countries with long coasts like Bangladesh lack the means to replicate those efforts, he said.

In big delta cities like Shanghai and Kolkata, zoning may provide some relief.