Electricity, transportation biggest U.S. polluters
By John Maday  |  Tuesday, December 08, 2009

The United States is second only to China in emissions of greenhouse gases, according to the new EPA report, with generation of electric power and vehicle emissions the leading sources.

The report, released on Dec. 7, officially states for the first time that the U.S. government believes “greenhouse gases threaten public health and the environment,” and that “science overwhelmingly shows greenhouse gas concentrations at unprecedented levels due to human activity.”

The full report, running 284 pages, notes that U.S. emissions from motor vehicles “are larger in magnitude than the total well-mixed greenhouse gas emissions from every other individual nation with the exception of China, Russia, and India, and are the second largest emitter within the United States behind the electricity generating sector.” Overall, the United States ranks second behind China in total greenhouse gas emissions.

Emissions from passenger cars, light- and heavy-duty trucks, buses, and motorcycles, including carbon dioxide, methane, nitrous oxide, and hydrofluorocarbons, are responsible for 23 percent of total annual U.S. greenhouse gas emissions, according to the report. Electricity generation contributes 34 percent. A third category listed as the “Industrial Sector” accounts for 19 percent of U.S. emissions. 

According to the EPA, in 2007, greenhouse gas emissions from the entire agriculture sector accounted for less than 6 percent of the U.S. total. The report also motes that land use, land use change, and forestry activities resulted in a net carbon soil sequestration of approximately 17.4 percent of total U.S. CO2 emissions and almost 15 percent of total U.S. greenhouse gas emissions.

 The report shows emissions for electricity generation increasing from 30.5 percent of the U.S. total in 1990 to 34.2 percent in 2007. The contribution of motor vehicles increased from 20.2 percent to 23.3 percent during the same period. The industrial sector contributed 24.5 percent to U.S. emissions in 1990, but dropped to 19.4 percent by 2007.

Small contributors are not in the clear, however, as the EPA’s conclusions could open the door to a host of environmental regulations. The report notes that the total emissions of greenhouse gases worldwide are from numerous sources and countries, with each country and each source category contributing a relatively small percentage of the total emissions. “In this situation,” the report reads, “addressing a global air pollution problem may call for many different sources and countries to address emissions even if none by itself dominates or comes close to dominating the global inventory.

Read the full report and other supporting information.

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