UN Issues Bleakest Climate Report

"It's the poorest of the poor in the world, and this includes poor people even in prosperous societies, who are going to be the worst hit," said Pachauri.

"It's the poorest of the poor in the world, and this includes poor people even in prosperous societies, who are going to be the worst hit," Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change (IPCC), told Reuters of the report, which took six years to see the light.

More than 100 nations in the UN climate panel agreed a final text after all-night disputes during which some scientists accused governments of watering down forecasts about extinctions and other threats.

The report said change, widely blamed on human emissions of greenhouse gases, was already under way in nature and that desertification, droughts and rising seas would hit hard in the tropics, from sub-Saharan Africa to Pacific islands.

"This does become a global responsibility in my view," said Pachauri who added he was still wearing the same suit as on Thursday morning because of the marathon talks.

The IPCC groups 2,500 scientists and is the top world authority on climate change.

It built on a previous IPCC report in February saying that human greenhouse gas emissions, mostly from burning fossil fuels, are very likely to be the main cause of recent warming.

Scientists said China, Russia and Saudi Arabia had raised most objections overnight seeking to tone down some findings. Other participants also said the United States, which pulled out of Kyoto in 2001 as too costly, had toned down some passages.

US delegates rejected suggested wording that parts of North America may suffer "severe economic damage" from warming.

Overall, the report was the strongest UN assessment yet of the threat of climate change, predicting water shortages that could affect billions of people and a rise in ocean levels that could go on for centuries.

Hunger, Extinction

Friday's study also said climate change could cause hunger for millions with a sharp fall in crop yields in Africa.

It said food security will be "severely compromised," with an additional 80 to 200 million people at risk of hunger by 2080.

By that date, sub-Sahara Africa may account for 40 to 50 percent of the world's undernourished, compared with about 25 percent today.

Even under optimistic scenarios, hundreds of millions more Africans are "very likely" — a 90 percent certainty — to face severe shortfalls in food and drinkable water by 2080.

"Climate-induced diseases," already a reality, will increases in the frequency and impact, including cholera, meningitis and dengue fever.

The report also said up to 30 percent of animal and plant species will be vulnerable to extinction if global temperatures rise by 1.5-2.5 C (2.7 F to 4.5 F).

Global warming It could rapidly thaw Himalayan glaciers that feed rivers from India to China and bring heatwaves for Europe and North America.

The phenomenon threatens to unleash more suffering in Africa than on any other continent this century.

Action Urged

Its findings are approved unanimously by governments and will guide policy on issues such as extending the UN's Kyoto Protocol, the main UN plan for capping greenhouse gas emissions mainly from burning fossil fuels, beyond 2012.

"This further underlines both how urgent it is to reach global agreement on reducing greenhouse gas emissions and how important it is for us all to adapt to the climate change that is already under way," said European Environment Commissioner Stavros Dimas.

"The urgency of this report, prepared by the world's top scientists, should be matched with an equally urgent response by governments," echoes Hans Verolme of the WWF conservation group.

Green and conservation groups also urged an immediate global response to the damning report, reported Agence France-Presse (AFP).

"The urgency of this report, presented by the world's top scientists, should be matched with an equally urgent response by governments," said Hans Verolme, director of the World Wildlife Fund's global climate change program.

"There's no escaping the facts: global warming will bring hunger, floods and water shortages. Poor countries that bear the least responsibility will suffer most -- and they have no money to respond."

Greenpeace International said the report is only a glimpse into an "apocalyptic future."

"The earth will be transformed by human induced climate change, unless action is taken soon and fast," campaigner Stephanie Tunmore told AFP.

The Friends of the Earth asked the world's rich nations to cut emissions to avert a looming "humanitarian catastrophe."