Freight Facts and Figures 2011
Table 5-16. U.S. Greenhouse Gas Emissions by Economic End-Use Sector: 1990-2009 (electricity-related emissions distributed among sectors)1
In addition to CO, NOx, and particulate matter emissions, the transportation sector releases large quantities of greenhouse gases (GHGs), such as carbon dioxide (CO2), methane, nitrous oxide, and hydrofluorocarbons. Transportation is responsible for about 27 percent of all greenhouse gases emitted in the United States and nearly 7 percent of all greenhouse gases emitted globally. (Intergovernmental Panel on Climate Change, Climate Change 2007: Synthesis Report (Geneva, Switzerland: 2008)) When emissions from electricity generation are allocated among end-use sectors (on the basis of each sector's share of electricity consumption), the industrial sector produces the largest amount of GHG emissions, followed closely by transportation.
From 1990 to 2009, transportation GHG emissions rose by 17 percent. However, transportation sector emissions decreased by 4 percent from 2008 to 2009, likely the result of the economic downtown and higher fuel prices, which led to a decrease in vehicle travel and fuel consumption.
Millions of metric tonnes of CO2 equivalent
Key: CO2 = carbon dioxide; R = revised.
1Emissions from electricity generation are allocated to each economic end-use sector on the basis of each sector's share of aggregate electricity consumption. This method assumes each sector consumes electricity that is generated from the national average mix of fuels according to their carbon intensity.
2Industry includes manufacturing, construction, and mining. Six manufacturing industries—petroleum refineries, chemicals, primary metals, paper, food, and nonmetallic mineral products—represent the vast majority of energy use and thus GHG emissions in the industrial sector.
3Includes emissions from military aircraft (14.3 million metric tonnes in 2009) and "other" transportation, primarily lubricants (8.5 million metric tonnes in 2009). Emissions from international bunker fuels are not included.
4Electricity-related emissions were not distributed to U.S. Territories.
Greenhouse gas (GHG) emissions include CO2, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. CO2 equivalent is computed by multiplying the weight of the gas being measured by its estimated Global Warming Potential (GWP). The Intergovernmental Panel on Climate Change developed the GWP concept to compare the ability of one GHG to trap heat in the atmosphere to another gas. Carbon comprises 12/44 of CO2 by weight. Numbers may not add to totals due to rounding.
U.S. Environmental Protection Agency, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2009, EPA 430-R-11-005 (Washington, DC: April 15, 2011), table ES-8, available at www.epa.gov/climatechange/emissions/usinventoryreport.html as of August 10, 2011.
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