Outsourced Carbon Emissions

Image Caption: China is by far the largest “exporter” of carbon dioxide emissions, as seen in this map of the net flow of emissions embodied in trade among the major exporting and importing countries. Arrows indicate direction and magnitude of flow; numbers are megatons (millions of tons). Credit: Steven Davis/Carnegie Institution for Science.


A new study by scientists at the Carnegie Institution for Science finds that over a third of carbon dioxide emissions associated with consumption of goods and services in many developed countries are actually emitted outside their borders. 


The study finds that, per person, about 2.5 tons of carbon dioxide are consumed in the U.S. but produced somewhere else. For Europeans, the figure can exceed four tons per person. Most of these emissions are outsourced to developing countries, especially China.

“Instead of looking at carbon dioxide emissions only in terms of what is released inside our borders, we also looked at the amount of carbon dioxide released during the production of the things that we consume,” says co-author Ken Caldeira, a researcher in the Carnegie Institution’s Department of Global Ecology.

Caldeira and lead author Steven Davis, also at Carnegie, used published trade data from 2004 to create a global model of the flow of products across 57 industry sectors and 113 countries or regions. By allocating carbon emissions to particular products and sources, the researchers were able to calculate the net emissions “imported” or “exported” by specific countries.