KEY POINTS:
The world's poor will be disproportionately harmed by climate change, the latest United Nations report on the effects of global warming made clear yesterday.
Existing divisions between rich and poor countries will be sharply exacerbated by the pattern of climate change, predicted in the study from the Intergovernmental Panel on Climate Change (IPCC).
Drought, crop failure, disease, extreme weather and sea level rise are all likely to fall much more heavily on the people of Africa, Asia and South America than on Europe, North America and Australia - which have done most to cause global warming and are best able to afford counter-measures to limit its consequences.
"Governments must act now to stop a catastrophe for the world's poor," said Benedict Southworth director of anti-poverty charity the World Development Movement.
"Climate change is no longer just an environmental issue, it is a looming humanitarian catastrophe," said Friends of the Earth International's climate campaigner, Catherine Pearce.
The IPCC chairman, Rajendra Pachauri said: "The poorest of the poor in the world - and this includes poor people in prosperous societies - are going to be the worst hit. People who are poor are least able to adapt to climate change."
The study, endorsed by all the major UN member states, was the second part of the IPCC's fourth assessment report. The first part, released two months ago, dealt with the science of climate change and likely future temperature rises. Yesterday's report details the potential impacts of those rises on the natural world and on human society.
It was released in Brussels only after an all-night argument in which some countries responsible for increasingly high greenhouse gas emissions, led by China, the US and Saudi Arabia, watered down the text from its initial draft.
However, the picture painted by the final consensus document was stark enough.
The impacts were already visible, the report said, with significant changes caused by rising temperatures apparent in ice masses, water bodies, agriculture and ecosystems. Changes consistent with higher temperatures range from melting permafrost in Arctic regions to shifting distributions of fish populations, and earlier timing of spring events such as leaf-unfolding and egg-laying.
But future impacts are potentially catastrophic. Up to 30 per cent of plant and animal species so far assessed are likely to be at increased risk of extinction if increases in global temperature exceed 1.5C to 2.5C.
The report adds: "The resilience of many ecosystems is likely to be exceeded this century by an unprecedented combination of climate change, associated disturbances ... and other global change drivers."
Because of the increasing number of studies combining supercomputer modelling of the global climate with projected trends, the report can set out changes region by region.
Africa is the worst case. "By 2020, between 75 and 250 million people [in Africa] are projected to be exposed to an increase of water stress due to climate change."
African agricultural production is projected to be "severely compromised by climate variability and change," with decreases likely in the area suitable for agriculture, the length of the growing season and yield. "In some countries, yields from rain-fed agriculture could be reduced by up to 20 per cent by 2020," the report says.
Other negative impacts for Africa include decreasing fish supplies and sea-level rise. By the end of the century the report says, the cost of dealing with the latter could be 10 per cent of a country's wealth.
Asia is not far behind. It will be hit by a water "double whammy" as Himalayan glaciers irreversibly melt - first increased flooding in glacier-fed rivers, then decreased water resources as the glaciers disappear. More than a billion people in Asia could be affected by 2050.
Asian coastal areas, especially the big cities in the seven "mega-deltas" from India's Ganges to China's Yangtze, will be at greatly increased risk of flooding and by 2050, crop yields in central and south Asia may drop by 30 per cent.
In Latin America, water supplies are predicted to be "significantly affected" by changes in rainfall patterns and the disappearance of Andean glaciers. Parts of the Amazon rainforest are likely to turn into semi-arid savannah, while in drier areas, there will be salinisation and desertification of agricultural land.
In the richer continents the effects will not be as severe and will be easier to defend against. Indeed, some may even be beneficial for a time: crop yields in North America may rise by up to 20 per cent, and there may be some agricultural benefits for Australia and New Zealand.
Europe will have to deal with the likely disappearance of its skiing industry, more heatwaves and flash flooding - but not mass starvation.
However, in the long-term any temporary benefits will be overwhelmed by the global damage.
- INDEPENDENT
