U.S. Carbon Emissions 20% Greater Than Official Estimate

The United States' role in climate disruption is far greater than most people realize. Not only does the U.S. emit more carbon dioxide (CO2) than any other nation besides China, not only does the U.S. have one of the highest per-capita emissions levels in the world, but the U.S. economy also accounts for a massive amount of emissions released by the rest of the world.

I crunched the numbers to see just how much CO2 the United States economy is actually responsible for. The results are disturbing. 

Every product and service requires energy, and thus carbon. Commercial agriculture requires petroleum or natural gas-based fertilizers and diesel fuel for planting and harvesting. Manufacturing requires energy to extract raw materials, petroleum to transport those materials to a factory, energy to convert those materials into products, and yet more petroleum to transport the products to end users. Even services like housecleaning or web site hosting have an energy cost, the former in the creation of chemicals and electric cleaning tools and the latter for the server (a product with its associated energy cost of creation), the electricity used to run the computer, and the energy consumed in constructing the computer center that houses the server. And in all cases, the energy cost to create the product or service creates carbon emissions.

Given this, the amount of CO2 that a product or service indirectly emits in its creation, transport and use can be estimated. And by extension, the total amount of CO2 produced by the combined products and services (gross domestic product) of a nation can be estimated. The total CO2 emissions from consumption of energy per dollar of a country's GDP is called carbon intensity.

The official carbon intensity of the United States in 2006, as noted by the Department of Energy, was 0.52 metric tons of CO2 emitted per thousand dollars (indexed for inflation to the value of the dollar in 2000). For comparison, the carbon intensity of Iceland in 2006 was 0.31 metric tons of CO2 per thousand dollars, and the carbon intensity of Russia was 4.54 metric tons of CO2 per thousand dollars.

The fact that carbon intensity varies from country to country is a function of the country's energy mix and overall productivity -- more coal or oil burned for electricity or heating produces higher carbon intensity, and lots of manual labor producing valuable products produces a higher carbon intensity, too. Large amounts of manual labor producing inexpensive products produces an extremely low carbon intensity, as witnessed by the very low carbon intensity of 0.10 metric tons of CO2 emitted per thousand dollars from Cambodia.

From carbon intensity, we can estimate the amount of CO2 produced in the process of creating the goods and services that the U.S. exports -- and that other countries export to us. The result is the following graph:

Figure 1

Figure 1 shows the 15 nations that "export" the most CO2 to the United States in goods and services used in the U.S. economy. In essence, anything the U.S buys that says "Made in China" is part of the U.S. economy, so the carbon emitted in the creation of that product belongs to the U.S. economy as much as the carbon emitted in manufacturing a Ford Focus in Detroit does. Figure 1 represents the balance of carbon, imported CO2 from other nations to the U.S. minus the CO2 the U.S. exports to them, as determined from the nations' carbon intensity. It's clear that China contributes by far the most CO2 to U.S. carbon emissions.

In words, the graph says that the U.S. exported over a billion metric tons of CO2 to the rest of the world in 2006.

Figure 2 below illustrates data in a similar fashion, but as a percentage of total U.S. carbon emissions: