No part of the world will be spared from climate shift if fossil-fuel gases -- carbon pollution which stores up heat from the Sun, causing Earth's surface to warm -- continues to be emitted at the present rate or at levels close to it, they said.

But even though everyone will be affected, it does not mean everyone will be affected equally.

Two most-vulnerable regions picked out on the second day of the scientific forum on climate change were Africa and South Asia.

The predictions are that higher global temperatures will change rainfall patterns there, adding to already acute water stress or alternatively boosting the risk of flooding and mounting a huge challenge to poor countries.

"Water shortages in many regions will make it more difficult to grow crops, to have industries and provide basic human needs for water and sanitation," said Bill Hare, a visiting scientist at the Potsdam Institute for Climate Impact Research in eastern Germany.

"These problems are likely to be acute in India, Pakistan, most of sub-Sahara Africa, especially in the south, where some countries could experience up to five- and 10-percent GDP (gross domestic product) losses," Hare told AFP.

Hare's scenario for this is a rise in the global average temperature of two C (3.6 F) above pre-industrial levels, which he estimates could be reached "within three to five decades" on current trends and policies.

At present, temperatures have increased 0.7-0.8 C above pre-industrial levels, and that is likely to double thanks to the inertia effect of gigatonnes of carbon pollution that have already been emitted.

"All the present studies indicate that Africa will be worst affected," said Tony Nyong, a doctor of environmental science at Nigeria's University of Jos and a member of the UN's top panel on climate change.

Nyong said that agriculture production in sub-Saharan Africa could fall by up to a third by 2060 because of changes in rainfall patterns and longer dry seasons, and coastal fisheries, particularly in the west of the continent, could be all but wiped out by warmer water.

One study determined that an additional 5.2 million people in South Africa alone could be at risk from malaria, as mosquitoes migrated to previously dry areas now moistened by rainfall.

"What makes Africa vulnerable is not just climate change but also poverty, AIDS and subsistence dependence on the ecosystem. All of these add to the challenge of adapting to climate change," Nyong said in an interview.

According to a 1993 study quoted by Rajendra Pachauri, chairman of the UN's top scientific authority on climate change, by 2050 as many as 150 million "environmental refugees" may have fled coastlines vulnerable to rising sea levels, storms or floods, or agricultural land that became too arid to cultivate.

In India alone, there could be 30 million people displaced by persistent flooding, while a sixth of Bangladesh could be permanently lost to sea level rise and land subsidence, according to the study.

Lin Erda, a professor at the Chinese Academcy of Agricultural Sciences, said his country was expecting a local temperature rise of 4 C (7.2 F) by 2080, translating to an increase of 80 centimetres (32 inches) in the sea level.

The greater warmth placed at risk a key ecological zone in the centre-north of the country that is a buffer between grassland and agricultural land, he said.

The rising sea levels meant the country would have to boost its coastal defences for high-population, vulnerable cities such as Guangzhou and Shanghai, he told AFP.

Most computer models say that global warming will also provide a few winners as well as many losers. Cold, dry northern regions in Canada and Russia are likely to become warmer and wetter, which will open them up to habitation and farming.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.