Climate Conversations : METHANE POLLUTION

methane noaaClyde Burnett, Peak to Peak.  Ben Franklin’s 1774 letter describing the emission of “flammable air” from the mud in ponds in PA and NJ inspired the identification of methane, the common name for CH4, by Volta in 1776. In 1854 Thoreau continued to describe the formation of “air” bubbles under the ice in Walden Pond. “Being curious to know what position my great bubbles occupied with regard to the new ice, I broke out a cake containing a middling sized one, and turned it bottom upward. It was perhaps slightly lenticular, with a rounded edge, a quarter of an inch deep by four inches in diameter; and I was surprised to find that directly under the bubble the ice was melted with great regularity. I inferred that the infinite number of minute bubbles which I had first seen against the under surface of the ice were now frozen in likewise, and that each, in its degree, had operated like a burning-glass on the ice beneath to melt and rot it.”

Thoreau’s limited observations were excellent, but his interpretation failed basic optics.

The bubble in ice would be a diverging lens. My Penn State physics lecture-demonstration students were highly amused by this, and a budding engineer in the back row explained that “The gas bubble was not a good conductor of heat as the adjacent ice.

The cold water under the bubble wasn’t losing heat through the bubble to the cold air outside as fast as the water nearby under the solid ice; it just didn’t freeze as rapidly.

Henry showed little interest in the source of the bubbles. Perhaps it’s just as well that he didn’t go so far as to hold a lighted candle near the bubble.

Methane is an important greenhouse gas with infrared absorption much greater than CO2, and at present greenhouse gas concentrations, its emission produces about 36% the global warming of CO2. Methane has a much shorter atmospheric lifetime, so it would be an effective short-term limit on global warming to control its emission. President Obama has announced a goal in the EPA Clean Power Plan to reduce methane emission by 40-45% by 2025. The Supreme Court has delayed this application at the request of businesses and states with economic interests in fossil fuel industries, but other states may elect to continue the project.

Industry claims its production of natural gas has a leakage emission rate of about 1%. But NOAA measurements in the Denver basin and independent measurements in Utah’s Uinta basin and the Los Angeles basin disagree. Recently there was a massive leak near Porter Ranch in California from a natural gas storage well that discharged  double the leakage of the entire LA basin. Residents were forced to evacuate. The Southern California Gas Co claims to have the leak under control after more than 3 months of continuous leakage.

NASA has reported on the satellite discovery of a methane emission hot spot in our Four Corners area of fossil fuel production that is believed to be due to fracking, as well as natural and other industrial leaks. These methane leaks are being further investigated and we await industry’s corrective response.