Oil and Gas Production a Major Source of Greenhouse Gas Emissions, EPA Data Reveals

offshore drilling rig

On Feb. 5, the U.S. Environmental Protection Agency (EPA) released new data indicating that in 2011, the oil and natural gas sector was the second-highest contributor of greenhouse gases such as carbon dioxide, methane, and nitrous oxide. A method of natural gas drilling, known as hydraulic fracturing or fracking, is a major component of this industry. Given this data and its stated commitment to addressing climate change, the Obama administration will have to reconsider its strong support of natural gas production.

EPA’s Greenhouse Gas Reporting Program

The data comes from an EPA database of greenhouse gas emissions from more than 8,000 industrial facilities, such as power plants and oil refineries. In 2008, Congress required the EPA to begin collecting the data, and last year the agency released initial greenhouse gas data from 29 source categories. The new 2011 greenhouse gas data includes 12 additional source categories for a total of 41 sources across nine major industries. The most notable expansion was the first-time inclusion of nine source categories that make up the oil and gas industry sector. The data was also expanded to include methane emissions, generally produced by large emitters in the oil and gas industry.

The greenhouse gas reporting program covers an estimated 85 to 90 percent of total greenhouse gas emissions in the United States. The data is limited because only facilities emitting 25,000 tons or more annually (equivalent to the carbon dioxide released from burning 131 rail cars worth of coal) are required to report. The data also excludes emissions from transportation and agricultural facilities.

The EPA released the greenhouse gas data in a publicly accessible web-based tool called FLIGHT (or Facility Level Information on GreenHouse gases Tool). The tool gives the public the ability to search and use greenhouse gas data to foster public awareness and/or encourage research on local environmental problems. Citizen activists can use the data to push for significant reductions in emissions in their communities. Companies can use the data to compare their performance against others in their sector and set goals for increased efficiency. State and local officials can also use the data to compare the effectiveness of their policies and practices with those operating in other parts of the country.

Oil and Gas Sector is the Second-Largest Source of Greenhouse Gases

Power plants remain the top U.S. emissions source, accounting for more than 2 billion metric tons, or a third of total U.S. "carbon dioxide equivalent" (carbon dioxide, methane, and other gases that contribute to climate change) in 2011. The oil and natural gas sector emitted 225 million metric tons of carbon dioxide equivalent that year, making it the second-largest major industry sector producing greenhouse gas pollution. Refineries came in third with 182 million metric tons of emissions. The top five sectors are listed in Table 1.

Table 1

Rank Main Industry Sectors Emissions
(Million Metric Tons CO2 equivalent)
1 Power Plants 2,221
2 Oil and Natural Gas 225
3 Refineries 182
4 Chemicals 180
5 Other (electronics, food processing,
manufacturing, military, etc.)

Among the source categories, which are subcategories of industry sectors, two oil and natural gas activities rank in the top ten being tracked. Onshore oil and gas production ranks third, and natural gas processing ranks sixth. Power plants and refineries are the only two industry sectors that do not have subcategories and are listed as their own source categories (see Table 2 below).

Table 2

Rank Source Categories Emissions
(Million Metric Tons CO2 equivalent)
1 Power Plants 2,221
2 Refineries 182
3 Onshore Oil and Natural Gas Production 94
4 Iron and Steel Production 91
5 Municipal Landfills 81
6 Natural Gas Processing 62
7 Cement Production 56
8 Petrochemicals 53
9 Hydrogen 34
10 Lime Manufacturing 31

While the oil and natural gas sector includes a wide range of exploration and production activities, fracking has become the primary method companies use to extract natural gas. Traditional drilling for oil and gas has declined as reservoirs of easy-to-access oil and gas have been depleted. The top oil and natural gas sources also indicate the large contribution fracking activities are making to the industry sector’s greenhouse gas emissions. The data was not collected on individual wells but instead aggregated emissions from large production areas or basins. The highest emissions came from New Mexico’s San Juan Basin and Texas’ Permian Basin, where advances in horizontal drilling and fracking have led to a boom in shale gas and shale oil production. Emissions from onshore production (which includes fracking) were primarily methane. Methane is a greenhouse gas that is 21 times more powerful than carbon dioxide.

In recent years, scientists and environmentalists have emphasized the polluting nature of fracking, despite the repeated claims by industry about "clean natural gas." A Cornell University study showed that fracking produces more greenhouse gas emissions over time than traditional methods of oil drilling or coal mining, due to hauling in large quantities of water by truck and the methane released from fracking wells. Since the EPA greenhouse gas data does not include emissions from transportation, the total amount of emissions contributed by the oil and gas sector is likely underreported. Greenhouse gas emissions are not the only concern involved in fracking; the drilling method has been linked to a growing number of cases of water and land contamination.

Administration’s Conundrum

In his inauguration speech last month, President Obama vowed to "respond to the threat of climate change," and the administration has already taken some action in this direction. The latest EPA greenhouse gas data make clear that that the Obama administration, as part of its approach to climate change, should pursue significant emissions reductions from the oil and gas industry and implement strong safeguards to rein in the pollution associated with fracking.


Climate change is the most significant environmental concern of our lifetimes, and comprehensive action is essential. The latest data on greenhouse gas emissions clearly establishes that the oil and natural gas sector emit considerably more greenhouse gas pollution than previously believed. If we are going to limit greenhouse emissions and address climate change, stronger pollution controls on oil and gas operations, as well as power plants, are needed.

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