Global warming may take its gravest toll on Africa, the world's poorest continent that lacks the resources to tackle the challenges posed by the possible environmental impact of rising temperatures. Scientists say that warming temperatures could reduce crop production, increase drought in some areas and flooding in others - heaping more misery on a continent already plagued by war, poverty, and the devastating AIDS epidemic.
Already scarce supplies of water could be further depleted and Africa's magnificent wildlife and stunning coral reef systems threatened. "With its low per capita fossil energy use, sub-Saharan Africa has the lowest emissions of the greenhouse gases that are the major cause of climate change," Dr Robert Watson, the head of the United Nation's Intergovernmental Panel on Climate Change (IPCC), said: "Yet Sub-Saharan Africa is the most vulnerable to climate change because widespread poverty limits its capabilities to adapt to a continuing change in climate."
"Africa is very much at risk it is very clear that poor people in poor countries and those in the tropics will be very severely affected," Ian Johnson, the World Bank's vice-president responsible for sustainable development, said: "Where one has concerns for Africa is in the agricultural sector where you already have relatively low yields." Many soils in Africa are poor and badly leached. Rising temperatures could promote desertification, the spread of severely degraded land with zero economic productivity and rainfall of less than 50 mm per year.
One estimate puts severely degraded land in Africa at around 30 million hectares and this is expected to rise, though by how much and how fast is hard to predict. The forecasts are not all doom and gloom. Scientists note that agricultural production in highland areas in countries such as Ethiopia, Kenya or Zimbabwe could actually benefit from warmer temperatures and reduced frosts. But that would require strategies of adaptation. "Even there (in the highlands) you would need to adapt to the changing environment. You would need the right strains of crops to adapt," said Johnson.
Climate change will be a mixed bag on a continent with the equator cutting through its heart. "Northern African countries and other desert areas could become drier while tropical regions could become wetter," said Ajay Mathur, the head of the World Bank's climate change unit: "The problem is that the number of rainy days could be the same or decrease in tropical areas but the rainfall could increase so you would have greater floods."
Rising sea temperatures attributed to global warming have been linked to the devastating floods that have lashed Mozambique for the past two years, killing hundreds and setting back development in one of Africa's fastest growing economies. "You have the El Nino effect which is more frequent than it was 20 years ago. We are moving towards an almost permanent state of El Nino," said Mathur, referring to the weather phenomenon which causes droughts, floods, fires and famine.
Environmentalists say the floods were worsened by the loss of vital wetlands in neighbouring countries that enabled water to flow over the ground and into rivers instead of seeping into the soil. Rising temperatures would put further pressure on these wetlands, which have already been eroded by over-grazing. A less immediate threat to coastlines stems from rising sea levels. "If sea levels rise, inundation could occur along more than 70 percent of the Nigerian coastline," said one IPCC report on the regional impacts of climate change in Africa: "With a one-metrerise in sea level, up to 600 square kilometres of land would be at risk. This includes parts of Lagos and other smaller towns along the coast."
Coral reefs and the fish populations they support are dying off around the continent and elsewhere, partly, scientists believe, because of rising sea temperatures. Climate change may also threaten many species of land animals which are among the continent's biggest tourist draws. "Recurrent droughts in the past decade have depleted wildlife resources significantly (in Africa). Permanent loss of such attractions would waste vast amounts of investment in tourism," the IPCC report said.
Vegetation and habitat - crucial to the well-being of many animals - will not respond quickly to climate change, and wildlife will be unable to migrate to more suitable climatic conditions because of limited corridors. Adaptable species already found in a range of diverse habitats, such as baboons, may not fare too badly. But gorillas and chimpanzees, which are highly endangered, could become extinct if the tropical forests they depend on for their survival retreat further because of climate change. Other tourist attractions, such as Victoria Falls on the Zimbabwean-Zambian border, could also lose their allure because of reduced river discharge and the alteration of the rainforest. One IPCC report says that in a warmer and more urbanised world, rodent populations and the diseases they spread, such as plague and hantavirus pulmonary syndrome, would rise.
Wetter areas in the tropics could increase mosquito populations and with them malaria, the continent's biggest killer. Add all of this to the mounting toll from HIV/AIDS and you have a terrifying combination of lethal diseases that could leave a trail of millions of orphans in their wake, deepening poverty and boosting crime and social strife. The predicted decreases in farming production would rip more holes in the unravelling social fabric. "Reduced food supplies and high prices immediately affect landless labourers who have little savings. The urban poor are indirectly affected by climate change through changes in prices and regional investment," says the IPCC. "Whatever is happening (with the climate) is being aggravated by the political and economic environment. Famines rarely occur outside of war and violent situations," said Richard Cornwall, an analyst at the Pretoria-based Institute for Security Studies.
Freitag, 24. August 2001