China is now the biggest emitter of greenhouse gases in the world, but its per-capita emissions are still less than those of the average U.S. citizen. In six years, that could flip, says a new report from the Netherlands Environmental Assessment Agency that was sponsored by the European Commission.

Current U.S. per-capita emissions are 16.9 tons, down from a peak of 19.7 tons. A host of factors, including peak travel, the decimation of the U.S. economy, and the continued shift toward moving manufacturing overseas could continue the downward trend, even as China's emissions continue to rise. Those two trend lines could cross in 2017.