Millions of people around the world face death and devastation due to floods, famine, drought and violence caused by global warming, according to a report by a charity group.

A report to be released Monday by Christian Aid, an association of the major churches in Britain and Ireland, said 162 million people in sub-Saharan Africa alone could die of disease directly attributable to global warming by the end of the century.

It urged the British government to lead the world's richer countries in taking urgent action to curb global warming.

Poorer regions, the charity added, should be encouraged to use renewable energy sources.

If sub-Saharan Africa switched from fossil fuels to other sources of energy, including solar, wind and water, the environment would benefit and there would be more jobs, better health and enhanced opportunities for learning, the report said.

It estimated that every household in Africa could change to clean, renewable energy sources for less money than it would take to pay the region's oil bill for the next decade.

Developing technology could even transform the world's most impoverished continent into a net exporter of clean energy, the report said.

"This report exposes clearly and starkly the devastating impact that human induced climate change will have on many of the world's poorest people," said Sir John Houghton, who has served on a scientific working group set up by the Intergovernmental Panel on Climate Change.

"That realization exposes an inescapable moral imperative for those of us in the developed world who have benefited so much from cheap energy from fossil fuels. We need to respond with urgent and determined action," he said.

The report warned of the possibilty of violence as people fight over resources made scarce in part by climate change.

In Kenya, the report said, there has been violence in drought-hit areas. In the north of the country, there have been killings in fighting over the right to water cattle at a diminishing number of watering holes.

In Bangladesh, it said, a predicted rise in sea levels could leave millions displaced and dispossessed. Already families in some areas must move every couple of years, as increased melt water from the Himalayan glaciers sweeps their land and fragile livelihoods away, the report said.