Final EPA report shows total US GHG emissions up 3.2% in 2010, total CO2 up 3.5%, total transportation CO2 up 1%
The US Environmental Protection Agency (EPA) has released the 17th annual US greenhouse gas (GHG) inventory. The final report shows overall emissions in 2010 increased by 3.2% from the previous year. EPA attributes the trend to an increase in energy consumption across all economic sectors, due to increasing energy demand associated with an expanding economy, and increased demand for electricity for air conditioning due to warmer summer weather during 2010.
Total emissions of the six main greenhouse gases in 2010 were equivalent to 6,822 million metric tons of carbon dioxide. These gases include carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride. The report indicates that overall emissions have grown by more than 10% from 1990 to 2010.
As the largest source of US greenhouse gas emissions, CO2 from fossil fuel combustion has accounted for approximately 78% of global warming potential (GWP)-weighted emissions since 1990, growing slowly from 77% of total GWP-weighted emissions in 1990 to 79% in 2010. Emissions of CO2 from fossil fuel combustion increased at an average annual rate of 0.7% from 1990 to 2010. The fundamental factors influencing this trend include (1) a generally growing domestic economy over the last 21 years; and (2) an overall growth in emissions from electricity generation and transportation activities, according to the report.
Between 1990 and 2010, CO2 emissions from fossil fuel combustion increased from 4,738.3 Tg CO2 Eq. to 5,387.8 Tg CO2 Eq.—a 13.7% total increase over the twenty-one-year period. From 2009 to 2010, these emissions increased by 181.6 Tg CO2 Eq. (3.5%).
From 1990 to 2010, transportation emissions rose by 18% due, in large part, to increased demand for travel and the stagnation of fuel efficiency across the US vehicle fleet. The number of vehicle miles traveled by light-duty motor vehicles (passenger cars and light-duty trucks) increased 34% from 1990 to 2010, as a result of a confluence of factors including population growth, economic growth, urban sprawl, and low fuel prices over much of this period.
When electricity-related emissions are distributed to economic end-use sectors, transportation activities accounted for 27% of US GHG emissions in 2010. The largest sources of transportation greenhouse gases in 2010 were passenger cars (43%), light duty trucks (19%), freight trucks (22%) and commercial aircraft (6%). These figures include direct emissions from fossil fuel combustion, as well as HFC emissions from mobile air conditioners and refrigerated transport allocated to these vehicle types.
From 2008 to 2009, CO2 emissions from the transportation end-use sector declined 4%, due largely to decreased economic activity in 2009 and an associated decline in the demand for transportation. From 2009 to 2010, CO2 emissions from the transportation end-use sector increased by 1% as economic activity rebounded slightly in 2010.
Transportation activities (excluding international bunker fuels) accounted for 32% of CO2 emissions from fossil fuel combustion in 2010. Virtually all of the energy consumed in this end-use sector came from petroleum products. Nearly 65% of the emissions resulted from gasoline consumption for personal vehicle use. The remaining emissions came from other transportation activities, including the combustion of diesel fuel in heavy-duty vehicles and jet fuel in aircraft.
The Inventory of US Greenhouse Gas Emissions and Sinks: 1990-2010 is the latest annual report that the United States has submitted to the Secretariat of the United Nations Framework Convention on Climate Change, which sets an overall framework for intergovernmental efforts to tackle the challenge posed by climate change. EPA prepares the annual report in collaboration with experts from multiple federal agencies and after gathering comments from stakeholders across the country.
The inventory tracks annual greenhouse gas emissions at the national level and presents historical emissions from 1990 to 2010. The inventory also calculates carbon dioxide emissions that are removed from the atmosphere by “sinks,” e.g., through the uptake of carbon by forests, vegetation and soils.