Caldeira Lab

The international supply chain of carbon dioxide emissions: Ken Caldeira

Click here to read about the paper



My post doc Steve Davis along with our colleague, Glen Peters, conducted a study where we tried to examine this entire supply chain from the point of extraction of fossil fuels to the point at which they’re combusted and released into the atmosphere and to the point where the product is consumed.

So the first thing we did is make a set of maps just showing for the carbon that is extracted from the ground in the form of fossil fuels and then exported to another country, what are those actual carbon flows in international trade from a fossil fuel as going from one country to another.

Then we asked another question saying, when the carbon is released to make consumer products and then those products are consumed in another country, what are the flows of embodied carbon? That is, what are the kind of virtual carbon that was released in one country but could be attributed to consumption in another country.

And then we put these two maps together and made a third map showing what is the net flow of fossil fuels from the point at which the fossil fuel is extracted tying that all the way through the production to the place where that’s consumed. For some countries, this really gives a window into what their fossil fuel emissions are and how they’re related to international trade.

Japan is a striking example, because they have very little domestic fossil fuel supply. If we look, for example, 7% of the carbon dioxide emissions that come from Japan are fuels imported from China. But then 11% of the emissions that can be associated with consumption in Japan are supported by imports of goods from China, where the CO2 was actually released in China.

If we put these two things together, we can see that 15% of Japan’s emissions are either due to goods that were produced in China or fossil fuels exported from China.

Davis, S. J., Peters, G. P., Caldeira, K. The supply chain of CO2 emissions. PNAS 2011, 108 (45) 18554–18559

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