Methane As a Greenhouse Gas

Methane can cause significant short-term harm in the atmosphere.

Methane is a colorless, odorless gas. It is the primary component of natural gas, produced at power plants, landfills and livestock farms. When cows digest their food, they produce methane gas. All livestock manure, including that of pigs and chickens, produces methane when naturally occurring microbes break it down, turning it into compost.

Methane is found in cavernous coal mines, and can poison miners. Canaries are used to detect the presence of methane. A dead canary indicates an abundance of trapped methane, a sign for miners to get to the surface quickly. Methane is also a greenhouse gas, one of six, but it is the most effective at trapping infrared radiation, preventing its passage into the atmosphere.

Power of Methane

Methane is 20 percent more effective at warming the planet than is carbon dioxide. However, methane lasts for only 12 years in the atmosphere; carbon dioxide can last up to 500 years. Chemical reactions with hydroxyl radicals in the stratosphere remove 90 percent of the methane, but over a long time, while methane can cause significant harm in a relatively short time.

Methane Sinks

There are chemical and biological processes, know as "sinks," for removing methane from the atmosphere. Naturally occurring microbes in soil, and chlorine atoms that result when pollutants mix in the ocean, can remove some methane. These two processes account for about 2 percent of methane removal, according to the U.S. Environmental Protection Agency.

Methane Control

Livestock farming helps capture methane for electricity generation.

Capturing methane and using it as a power supply is another mechanism for decreasing methane in the atmosphere. Livestock farms install bioreactors filled with manure and other waste. Under contained, heated, anaerobic conditions, microbes react, producing methane that is then captured and transferred to run on-site generators that meet all of the farm's heat and electricity needs. This technology is being applied to landfills and implemented around the globe in the private and public sectors.

Ozone

Ground-level ozone is a human health problem. Ozone is another word for smog produced when methane reacts with nitrogen oxides and non-methane hydrocarbons (i.e., oil and coal, not gas). Ground-level ozone damages living tissues; most damaging when inhaled, it burns lung tissues, according to the EPA. In contrast, atmospheric ozone is beneficial, providing a shield from solar radiation. Ground-level ozone is a major contributor to lung disease. Decreasing overall methane emissions cuts down on ozone production. Cuts in nitrogen oxide to not affect ozone levels.

Benefits

Decreasing methane emissions has many benefits. Less methane will quickly reduce the amount of infrared radiation trapped on Earth. Capturing methane gas and using it for electricity generation is a cost-effective and clean source of energy, which in turn reduces reliance on oil and other fossil fuels, helping to further reduce greenhouse gases in the atmosphere.

References

• U.S. Environmental Protection Agency: Methane
• National Oceanic and Atmospheric Administration: Linking Climate and Air Pollution
• EPA: Ground Level Ozone