|GHG emissions by the four end-use sectors, plus electrical generation. Click to enlarge.|
The US Environmental Protection Agency (EPA) has released the current national greenhouse gas inventory, which finds that net overall emissions—factoring in sources and sinks—rose 0.83% in 2005 from 2004 to 6,431.9 Tg CO2e. Emissions from transportation rose 1.6% during the same period to 1,897.9 Tg. Transportation continues to be the largest contributor of the four end-use sectors.
The report, Inventory of US Greenhouse Gas Emissions and Sinks: 1990-2005, was published after gathering comments from a broad range of stakeholders across the country.
The report indicates that net emissions (sources and sinks) have grown by 16.3% from 1990 to 2005, while the US economy has grown by 55% over the same period. The greenhouse gas intensity of the economy is decreasing—i.e, the carbon efficiency per unit GDP is increasing—although the absolute amount of emissions continues to climb.
Transportation activities (excluding international bunker fuels) accounted for 33% of CO2 emissions from fossil fuel combustion in 2005. Virtually all of the energy consumed in this end use sector came from petroleum products. More than 60% 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.
Transportation emissions grew by 29.4% during the 1990-2005 period—for a CAGR of 1.7%—and accounted for approximately 41% of the growth in energy-related CO2 emissions from all sectors.
Within the transportation sector, highway emissions have grown 34.4% during the 15-year period, while highway vehicle kilometers traveled increased by 39.4%, according to data from the Federal Highway Traffic Safety Administration. While transportation is thus proving more efficient, it still is delivering an on-going increase in emissions.
EPA prepares the annual report in collaboration with multiple federal agencies. This report is the latest in an annual set of reports that the United States submits to the Secretariat of the United Nations Framework Convention on Climate Change.