Catastrophic global warming due to fossil-fuel burning is unlikely because oil and gas will run out too quickly, scientists have claimed. The controversial theory forecasts that all the fuel will be burned before there is enough carbon dioxide in the atmosphere to bring into reality melting ice-caps and searing temperatures. Geologists at Uppsala University in Sweden claim there are not sufficient reserves of oil and gas left in the world for even the most modest of the scenarios put forward by the Intergovernmental Panel on Climate Change (IPCC) to come to pass. Predictions of global meltdown by the IPCC created the drive for the Kyoto Protocol, an international agreement requiring compliant nations to restrict their emissions. In response to the controversial theory, published today in the journal New Scientist, the IPCC staunchly defends its predictions, saying it had considered a range of estimates of oil and gas reserves, and drawing attention to the fact that coal-burning could easily make up the shortfall claimed by the Swedish scientists. The IPCC put forward a range of future scenarios, from extravagant consumption of oil and gas to a quick change-over to greener energy sources. Although estimates of oil and gas reserves vary widely, the Swedish researchers represent a growing body of experts who claim oil supplies will peak by 2010, and gas shortly after. They believe oil and gas reserves amount to the equivalent of 3,500 billion barrels - much less than the 5,000 billion barrels estimated in the IPCC’s most optimistic model.