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NewsAsia, 2 Feb 05 Refugees, disease, water and food shortages to result from global warming EXETER, England : Global warming will boost outbreaks of infectious disease, worsen shortages of water and food in vulnerable countries and create an army of climate refugees fleeing uninhabitable regions, a conference here was told. The scale of these impacts -- the theme of the second day of the major scientific forum on global warming -- varies according to how quickly fossil fuel pollution is tackled, how fast the world's population grows and how well countries can adapt to climate shift. But a common expectation is that widespread misery is lurking, a few decades down the road. According to a 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. Pachauri's body, the Intergovernmental Panel on Climate Change (IPCC), estimated in 2001 that by 2100, temperatures would rise by between 1.4 C (2.5 F) and 5.8 C (10.4) compared to 1990 levels, driven by atmospheric carbon pollution which stokes up heat from the Sun. The mean global sea level would rise by between nine and 88 centimetres (four and 35 inches). Those increases depend on whether carbon dioxide (CO2), doubles or nearly quadruples from the pre-industrial levels of 280 parts per million (ppm). Global warming will also add significantly to Earth's worrisome water problems. Already around 1.4 billion people live in water-stressed areas, a term defined as having less than 1,000 cubic metres (35,000 cubic feet) of water per person per year, said Nigel Arnell of the Tyndall Centre for Climate Change Research at Britain's University of Southampton. Most of them live in southern and southwest Asia, the Middle East and the Mediterranean. By the 2050s, water availability in these water-stressed regions -- but also in parts of central, north and south America -- may be further crimped because of changed rainfall patterns. Between 700 million and 2.8 billion people in such areas will be affected, depending on population growth and the pace of temperature rise. Sari Kovats of the London School of Hygiene and Tropical Medicine put forward a study co-authored by four World Health Organisation (WHO) scientists that gives a snapshot of global health problems caused by climate change. Between the 1970s -- when temperatures first rose significantly -- and the year 2000, climate change cost around 150,000 lives from malnutrition, diarrhoea, malaria and floods. That tally will "approximately double" by 2020, mainly because of diarrhoea, which is propagated easily in floods, and hunger, Kovats said. The basis for this calculation is "business as usual," in other words, no controls are put on carbon pollution, causing Earth's temperature to reach some four C (7.2 F) higher at the end of this century when compared with 1990. "Climate change will bring some health benefits," but these will mainly go to northern countries, where fewer people will die of cold and crop yields will be better, his study said. Overall, these benefits will be hugely outweighed by increased disease and malnutrition. Bill Hare, a former Greenpeace campaigner who is visiting scientist at the Potsdam Institute for Climate Impact Research in eastern Germany, said a two C (3.6 F) rise seemed to be a key threshold. "Above two C, the risks increase very substantially, involving potentially large extinctions or even ecosystem collapses, major increases in hunger and water shortage risks as well as socio-economic damages, particularly in developing countries," said Hare. The conference wraps up on Thursday with a set of conclusions about the current state of knowledge about the dangers of global warming. The document will be submitted to Group of Eight (G8) policymakers and the IPCC for consideration in its next big report, due out in 2007. - AFP Triggers to climate catastrophe still poorly understood EXETER, England : Scientists at a global warming conference say they see potential triggers for runaway climate change but admit that when and how these notional doomsdays may be unleashed are debatable or quite unknown. The theoretical triggers are the apocalyptic side to global warming, giving the lie to the common perception of it as an incremental threat that will rise predictably, like a straight line on a graph. A widespread view of climate change is that the Earth's surface temperature will gently rise as more and more carbon gas is spewed out by fossil fuels, trapping heat from the Sun. The change would be progressive, which means humans would have enough time to respond to the crisis and plants and animals have a better chance of adapting to its effects. But scientists at a conference here on global warming say there is also the risk of sudden, catastrophic, irreversible and uncontrollable climate change that could be triggered in as-yet unknown conditions. "There's still a great deal we don't know about these rapid non-linear events," British scientist Sir John Houghton, a leading member of the UN's top panel on global warming, said on Tuesday. One scenario centres on the future of the Gulf Stream, the current that brings warm water to the northeastern Atlantic from the tropics and gives Western Europe a climate that is balmy for its northern latitude. What would happen to this oceanic conveyor belt if cold fresh water were dumped on it from melting polar ice and changed rainfall patterns, the result of warm weather? When this idea was first put forward in the late 1990s, some doomsters predicted the Gulf Stream would stop, pitching Britain, Ireland and much of coastal western Europe back into an Ice Age. But two computer models, put forward Tuesday, show how far scientists fail to agree on the probability of this event and on its likely impact. University of Illinois professor Mike Schlesinger told AFP that he had modelled a "business as usual" simulation in which the world continued with uncontrolled emissions of the carbon gases that cause global warming. "I was surprised to find out that it's 70-percent likely that there will be a shutdown in this circulation over a 200-year timeline," he said. "Over Europe, the shutdown would cause a cooling of perhaps one or two degrees [C, 2-4 F], superposed on [several degrees of] warming," he said. "So what you get is a smaller warming in Europe, you don't get an Ice Age out of that." Just as remarkable was this discovery: the shutdown caused such a disruption in global weather patterns that Alaska became a lot warmer in winter. "This is serious news for the permafrost," he said. In contrast, Richard Wood, of Britain's Hadley Centre for Climate Centre and Research, was far more cautious. "Little can currently be said about the probability, except that it is subjectively considered low during the 21st century," Wood's study said. His simulation -- entirely hypothetical -- of the Gulf Stream shutdown suggests that parts of Britain would be far colder than the so-called Little Ice Age of the 17th and 18th centuries, when winter "Frost Fairs" were held on the frozen River Thames. Worst hit would not be Alaska, but central America, where farm production would fall by 106 percent, according to this calculation. Another doomsday worry is about the future of carbon which is already stored in the soil in the form of decayed leaves and rotting vegetation, and in the capacity of the sea to go on absorbing man-made carbon pollution. Scientists at the conference agreed that if temperatures go beyond a threshold, this stored carbon in the soil will be released into the air. And at some point, the sea, which has already absorbed 48 percent of the carbon dioxide emitted by burning oil, gas and coal, will no longer be able to absorb any more pollution. That means vast amounts of gas will be dumped into the air, amplifying the global warming crisis at a stroke. But carbon storage in such vast and complex mechanisms is a complex and little-understood phenomenon. "The precise point at which the land biosphere will start to provide a positive feedback [i.e. release CO2 into the air instead of storing it] cannot yet be predicted with certainty," says Peter Cox of Britain's Centre for Ecology and Hydrology. "This depends on a number of poorly understood processes, such as the long-term response of photosynthesis and soil respiration to increased temperatures and the possible acclimation of photosynthesis to high CO2." - AFP links Related articles on Global issues: global warming issues, policies |
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