The study, "China Energy Report", found that by 2020, China's burning of fossil fuels could annually emit CO2 equal in mass to 2.5 billion tonnes of pure carbon and up to 2.9 billion tonnes, depending on varying scenarios for development and technology. By 2030, those annual emissions may reach 3.1 billion tonnes a year and up to 4.0 billion tonnes.
The report did not give its own estimate of China's current emissions, but cites data from a US Department of Energy that put them at 1.4 billion tonnes of carbon in 2004.
Last year a Chinese government report estimated that by 2050 the country's total greenhouse-gas emissions could reach 2.0 billion tonnes of carbon a year.
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