By 2100, the average world temperature could rise between 2.5 and 10.4 degrees Fahrenheit, according to a report released today in Shanghai by the U.N.-sponsored Intergovernmental Panel on Climate Change. This estimate is significantly higher than the 1.8- to 6.3-degree rise predicted by the IPCC in 1995. The Shanghai report, the third such assessment by the IPCC, asserts more strongly than in the past that humans have “contributed substantially” to the warming of the atmosphere by burning fossil fuels. International negotiations over what to do about global warming have stalled, mostly because of U.S. obstinacy. IPCC Chair Robert Watson couldn’t help but take a dig at the U.S.: “A country like China has done more, in my opinion, than a country like the United States to move forward in economic development while remaining environmentally sensitive.”