China has been using up to 17 percent more coal a year than reported, which means that almost a billion more tons of carbon dioxide, a greenhouse gas, is being released annually.
The increase alone is greater than Germany's annual emissions from fossil fuels, and the numbers could complicate the already difficult talks to address global warming.
On Saturday, the presidents of Taiwan and China will meet in Singapore, the first such meeting since 1949, although no agreements are expected.
