Let’s go ahead and state the obvious: It will be impossible to hash out any sort of global agreement on climate change if we can’t even agree on how much carbon-dioxide different countries are actually putting into the air.
Yet the data on this can be surprisingly unreliable — particularly in the case of the world’s biggest carbon emitter, China. A new paper in Nature Climate Change finds that there’s a real mystery as to how much carbon China is actually emitting. The national-level statistics say one thing. The provincial-level statistics say another. And the gap between the two numbers came to about 1.4 gigatons in 2010 — a staggering amount, equivalent to all the carbon-dioxide that Japan put into the air that year.