Its estimates, in a major report unveiled in Brussels, say the magnitude of climate-change effects will vary according to the size of the world's population, energy use and the level of greenhouse gases in the atmosphere, which determines the rise in global temperature.

But under any scenario, the world's most populous region will be badly hit.

Here are the major findings:

-- 120 million to 1.2 billion people in Asia will experience increased water stress by 2020, and 185 to 981 million by 2050.

-- Cereal yields in South Asia could drop in some areas by up to 30 per cent by 2050.

-- Even modest rises in sea levels will cause flooding and economic disruption in densely-populated mega-deltas, such as the mouths of the Yangtze in China, the Red River in China and Vietnam, and the Ganges-Brahmaputra delta in low-lying Bangladesh.

-- Cholera and malaria could increase, thanks to flooding and a wider habitat range for mosquitoes.

-- In the Himalayas, glaciers less than four kilometres (2.5 miles) long will disappear entirely if average global temperatures rise by 3 degrees Celsius (5.4 Fahrenheit). This will initially cause increased flooding and mudslides followed by an eventual decrease in flow in rivers that are glacier-fed.

-- Per capita water availability in India will drop from around 1,900 cubic metre (66,500 cubic feet) currently to 1,000 cu. metres (35,000 cu. ft.) by 2025.

-- Some 30 per cent of Asian coral reefs, which sustain a large per centage of marine life, are expected to be lost in the next 30 years, although this will occur as a result of multiple stresses and not just climate change.

(Document: Working Group II contribution to the Intergovernmental Panel on Climate Change, Fourth Assessment Report).

Agence France-Presse