I have wondered that too. I haven't found CO2 specific measures, but I did find this: > And what he found was that the decline in pollution wasn't driven by of

I have wondered that too. I haven't found CO2 specific measures, but I did find this: > And what he found was that the decline in pollution wasn't driven by offshoring. US factories were genuinely finding ways to cut emissions. In fact, the industries that saw the biggest drops in pollution intensity actually grew as a share of output. https://www.vox.com/2015/2/8/7999417/US-factory-pollution-offshoring https://www.vox.com/2015/2/8/7999417/US-factory-pollution-of... But another paper (although this is from 2008) did find: > Our results indicate that international trade is a significant factor in explaining the change in emissions in many countries, from both a production and consumption perspective. https://www.pnas.org/doi/10.1073/pnas.1006388108 https://www.pnas.org/doi/10.1073/pnas.1006388108