Methane, also known as natural gas, is found at a concentration of nearly 2 parts per million in Earth’s atmosphere. It comes from a wide range of natural sources, including decay in swamps and seepage from the Earth’s crust.
Methane is also derived from human activities, including seepage from coal mines and natural gas wells, the belches of cows, and the cultivation of rice in wet soils. In fact, human sources of methane now exceed natural sources—which explains why methane concentrations have been increasing in Earth’s atmosphere.
At first glance, we might not be alarmed by the increase in methane. It’s naturally oxidized, so it has a lifetime of only about 10 years in the atmosphere. But, methane is a gas that contributes to the Earth’s greenhouse effect; in fact, methane is about 25X more effective in warming the atmosphere than carbon dioxide.
Some argue that the best way to combat climate change is to tackle the increase in atmospheric methane. That’s easier said than done. Human-derived methane sources are spread in a multitude of locations, making it more difficult to capture than carbon dioxide from power plants.
The oil and gas industry is responsible for only about 10% of the total sources of methane in Earth’s atmosphere. Cutting down on inadvertent emissions from gas wells would be a good way to start reducing methane emissions, but by no means will that solve the global warming problem.
**********
.
Web Links
Photo, taken on May 26, 2008, courtesy of Mike Love via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.