The US Environmental Protection Agency (EPA) on 18 August 2015 proposed regulations to reduce emissions of methane. These regulations would be the first to directly restrict methane emissions by the oil and gas industry; they build on a 2012 rule that sought to curb volatile organic compounds (VOCs) from hydraulic fracturing (fracking) to extract natural gas. Combined, the two regulations could reduce the oil and gas sector’s methane emissions by up to 30% by 2025, compared with 2012 levels, EPA says.
The proposed EPA regs are part of a larger effort by the White House to reduce national methane emissions by 40–45% by 2025. [See go.nature.com/o6uzlj for more detail.] But methane has only negligible influence on climate — contrary to popular belief and contrary to the claims of the IPCC, the UN’s climate science panel. Basic physics does not support White House policies to control methane emissions.
Methane occurs naturally as a trace gas in the earth’s atmosphere. Its chemical formula is CH4, one atom of carbon surrounded by four atoms of hydrogen. It forms the most important constituent of natural gas, an excellent fuel for generating heat and electricity. When burnt (oxidized), its products are carbon dioxide (CO2) and water vapor (WV). It is also a greenhouse (GH) gas, which by definition means it absorbs radiation at certain wavelengths in the infrared (IR) part of the electromagnetic spectrum. But contrary to UN-IPCC claims, basic physics reveals that its influence on climate is insignificant.
Methane has many sources, both natural (about half) and anthropogenic. The major natural sources are wetlands, swampy areas and bogs; the human-related sources are traditional agricultural ones, related to the growth of world population: rice paddies and cattle raising (flatulence from ruminants). More recent sources also include landfills and leaks from oil and gas operations. Coalmines also emit some methane that occasionally cause explosions there.
There are also many natural sinks of methane, including ozone and hydroxyl (OH) radicals in the troposphere (lower atmosphere). The combination of sources and sinks leads to an atmospheric lifetime of approximately 10 years.