"Already seven times more livelihoods are devastated by natural disasters than by war worldwide, at the moment, and this is going to be much worse, the way the climate is developing," Jan Egeland told AFP after addressing the top governing body of the Christian aid organisation World Vision.

"Climate change, it's happening. It's not a threat. It's happening today and those who suffer the most are the poorest in Africa. Where there was already drought, the droughts are getting worse. Where there was already flooding the floodings are getting worse, as we speak," said Egeland, the United Nations head of humanitarian affairs from 2003-2006.

He called for dramatic changes in lifestyles "if we are to avoid having disasters virtually every month in large parts of the world."

Speaking in a hotel meeting room where the air conditioning had been set to a chilly 18 C (64 F), he said hotels will have to raise their temperatures and in cold countries, heating will have to be reduced, while international travel cannot continue as it is.

Carbon dioxide from energy use is a major contributor to the greenhouse gases that scientists blame for the earth's warming.

A key UN report released earlier this year warned that billions would face a higher risk of water scarcity and millions more would likely go hungry as damage to the Earth's weather systems from greenhouse gases changed rainfall patterns, powered up storms and increased the risk of drought, flooding and water stress.

In March, Egeland was named special adviser on conflict prevention to UN Secretary General Ban Ki-moon.

Egeland, a Norwegian, is to assist Ban on matters relating to the prevention and resolution of conflicts and will help bolster UN capacity for peacemaking and good offices, a UN spokesperson said at the time.

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