Energy-related U.S. emissions of carbon dioxide fell 12% from 2005 to 2015, according to the Energy Information Administration (EIA).
Nearly 70% of these reductions were driven by electricity-generating plants shifting from coal to natural gas, which releases about half as much CO2 as coal when burned.
The rest of the decline was a result of energy efficiency in homes, industry, and transportation; growing use of renewable energy; and milder weather, says EIA’s Paul Holtberg. Overall, energy-related activities were responsible for more than 80% of U.S. CO2 emissions.
The drop in energy sector CO2 emissions came despite a 15% growth in the U.S. economy over the same period, EIA reports. In fact, U.S. CO2 emissions fell by 23% per unit of gross domestic product, says Holtberg, who credits transportation and home appliance efficiency as well as a general shift to less energy-intensive industrial production.
Holtberg predicts, however, that energy-related CO2 emissions are likely to stabilize in the near term, along with natural gas prices, which are expected to flatten. The country’s trend away from coal matches global trends, but EIA’s report shows a greater U.S. CO2 decline.
CO2 emissions may rise for the U.S. chemical industry as it increases output to take advantage of cheap, abundant natural gas, Holtberg says. However, new U.S. chemical plants are likely to be more efficient than and draw production from older, less efficient facilities in other parts of the world. The result, he says, could be greater U.S. CO2 emissions but lower global CO2 emissions.