EPA Releases Inventory of U.S. Greenhouse Gas Emissions & Sinks

On April 15, 2011 the EPA released its inventory of U.S. greenhouse gas emissions and sinks for the period of 1990 - 2009. Within the inventory you'll find statistics for both the problems and the benefits that livestock agriculture contributes to greenhouse gas and its effect on climate change. Up front it's important to recognize that livestock agriculture is a relatively small contributor especially with regard to CO₂. This is illustrated in the following from the executive summary. Clearly we as consumers have a stronger role in reducing greenhouse gases.

“As the largest source of U.S. greenhouse gas emissions, CO₂ from fossil fuel combustion has accounted for approximately 78 percent of GWP-weighted emissions since 1990, growing slowly from 77 percent of total GWP weighted emissions in 1990 to 79 percent in 2009.

Emissions of CO₂ from fossil fuel combustion increased at an average annual rate of 0.4 percent from 1990 to 2009. The fundamental factors influencing this trend include (1) a generally growing domestic economy over the last 20 years, and (2) overall growth in emissions from electricity generation and transportation activities. Between 1990 and 2009, CO₂ emissions from fossil fuel combustion increased from 4,738.4 Tg CO₂ Eq. to 5,209.0 Tg CO₂ Eq.—a 9.9 percent total increase over the twenty-year period.

From 2008 to 2009, these emissions decreased by 356.9 Tg CO₂ Eq. (6.4 percent), the largest decrease in any year over the twenty-year period. Historically, changes in emissions from fossil fuel combustion have been the dominant factor affecting U.S. emission trends. Changes in CO₂ emissions from fossil fuel combustion are influenced by many long-term and short-term factors, including population and economic growth, energy price fluctuations, technological changes, and seasonal temperatures.

In the short term, the overall consumption of fossil fuels in the United States fluctuates primarily in response to changes in general economic conditions, energy prices, weather, and the availability of nonfossil alternatives. For example, in a year with increased consumption of goods and services, low fuel prices, severe summer and winter weather conditions, nuclear plant closures, and lower precipitation feeding hydroelectric dams, there would likely be proportionally greater fossil fuel consumption than a year with poor economic performance, high fuel prices, mild temperatures, and increased output from nuclear and hydroelectric plants.

In the long term, energy consumption patterns respond to changes that affect the scale of consumption (e.g., population, number of cars, and size of houses), the efficiency with which energy is used in equipment (e.g., cars, power plants, steel mills, and light bulbs) and behavioral choices (e.g., walking, bicycling, or telecommuting to work instead of driving).”


A great YouTube video map on US CO₂ is also worth a watch. See it at http://youtu.be/eJpj8UUMTaI. It was uploaded by Purdue University.