Marc Karell
The USEPA recently released its 17th annual U.S. GHG emissions inventory, The Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2010
(http://epa.gov/climatechange/emissions/usinventoryreport.html). The report shows overall GHG emissions in 2010 increased by 213 million metric tons or 3.2% from the previous year, despite a recession. About 77% of all GHG emissions derive from fossil fuel combustion. From an industry sector, about 34% of total net GHG emissions (taking GHG emission sinks into consideration) derive from electricity generation, about 27% of the net total from transportation, and about 20% of the net total from industrial. Energy demand reportedly rose in 2010 due to growth attempts by companies and increased electricity demand for air conditioning due to a relatively warm summer in 2010.
Total emissions of the six main GHGs in 2010 were equivalent to 6,822 million metric tons of carbon dioxide equivalents, representing an increase by over 10% from 1990. In the Kyoto Protocol (not enforced because it was never approved by the US Senate), the US was supposed to reduce GHG emissions by 7% from the 1990 baseline by 2012. Although the Kyoto Protocol does not apply to the US, as a member of the UN, it must report net GHG emissions to the UN Framework Convention on Climate Change.
Other significant contributors to the inventory included methane emissions from natural gas systems, fermentation, and landfills; N2O emissions from agricultural practices; and SF6 emissions from electrical transmission. Remember that these GHGs have Global Warming Potentials significantly greater than CO2’s. The inventory also tracks “sinks” that remove CO2 emissions from the atmosphere. In fact, the amount of CO2 estimated to have been removed from the atmosphere by renewed forests rose by under 2% in 2010 compared to 2009. The success of cropland in the US as a sink declined in 2010.
The USEPA will undoubtedly use this information to develop future policy and focus attention on those segments most responsible for GHG emissions when developing new rules.
The Executive Summary of the GHG emissions inventory: http://epa.gov/climatechange/emissions/downloads12/US-GHG-Inventory-2012-ES.pdf
