"It is clear that a failure to address climate change is a failure to protect children," said UNICEF UK director David Bull. "Those who have contributed least to climate change -- the world's poorest children -- are suffering the most."

The report said climate change could add 40,000-160,000 child deaths a year in Asia and Sub-Saharan Africa through lower economic growth.

It also noted that if temperatures rose by two degrees Celsius above pre-industrial levels, up to 200 million people globally would face hunger -- a figure that climbs to 550 million with a temperature rise of three degrees.

The UNICEF report said economic damage due to climate change would force parents to withdraw children from schools -- often the only place they are guaranteed at least one meal a day -- to fetch water and fuel instead.

Environmental changes wrought by climate change will also expand the range of deadly diseases such as malaria, which already kills 800,000 children a year and is now being seen in previously unaffected areas.

Scientists predict global average temperatures will rise by between 1.6 and 4.0 degrees Celsius this century due to carbon emissions from burning fossil fuels for power and transport, causing floods, famines, violent storms and droughts.

An international agreement is being sought on action to ensure temperatures do not rise more than 2.0 degrees.

INEVITABLE

But some environmentalists say a 2.0 degree rise is inevitable whatever action is taken now. That is partly because of the 30-year time lag in climate response to emitted carbon, and partly because nations like China, which opens a new coal-fired power station a week, cannot and will not stop burning carbon.

China, with vast coal reserves and an economy growing at 10 percent a year, is set to overtake the United States as the world's biggest carbon emitter.

Developing nations, under pressure to sign up to new curbs on carbon emissions at the end of next year, say there is no reason they should keep their people in poverty when the problem has been caused by the developed world.

"Rich countries' responsibility for the bulk of past emissions demands that we give our strong support," said Nicholas Stern, whose 2006 report on the economic implications of the climate crisis sparked international concern.

"Business-as-usual or delayed action would lead to the probability of much higher temperature increases which would catastrophically transform our planet," he wrote in a foreword to Tuesday's report.

"It will be the young and the poor and developing countries that will suffer earliest and hardest.

"We cannot allow this to happen."