Berkeley Lab Discovers Bay Area Methane Emission May Be Twice As High As Previously Thought

Methane emissions in the Bay Area may be nearly twice as high as previously estimated, according to a new report from the Department of Energy’s Lawrence Berkeley National Laboratory, known more simply as the Berkeley Lab.

The gas, implicated as greenhouse gas contributing to climate change, escapes from environmental sources such as landfills, animals used in agriculture, wastewater and wetlands, as well as from leaking natural gas pipelines. According to the new paper, published in the journal Geophysical Research Letters and written by a team of researchers led by Seongeun Jeong and Marc Fischer, methane emissions are around 1.8 times higher than the amount previously estimated in the area.

They found that about 82 percent of the emissions come from environmental sources like landfills, while around 17 percent comes from natural gas lines. Leaked natural gas accounts for between 0.3 percent and 0.5 percent of the region's consumption of the fossil fuel.

Fischer notes that the amount of methane escaping from landfills could potentially be harnessed as a source of fuel, as an alternative to extractive approaches used in mining natural gas.

“This study, along with a few others we’ve published recently, quantifies greenhouse gas emissions from multiple source sectors in a way that will both enable evaluation of AB32 (the California Global Warming Solutions Act) and help guide efforts to mitigate emissions in the future,” Fischer said in a press release.

About 10 percent of all of California's methane emissions come from the Bay Area, the authors note.

“We wanted to know the emissions contribution from urban natural gas infrastructure, so we picked the Bay Area because it doesn’t have significant petroleum production,” said Jeong.

In the short run, methane traps much more heat than carbon dioxide, the more common greenhouse gas. It traps around 83 times the amount of heat as carbon; however, it stays in the atmosphere for only around 10 years, while carbon dioxide can persist in the the air for a century.

“We believe methane is 10 to 15 percent of California’s total greenhouse gas emissions on a 100-year timescale,” Fischer said. “If we are to reduce total emissions by 80 percent in 2050, we would have a very much harder time doing that if we don’t also reduce methane.”

The researchers collaborated with others at the University of California-Irvine, the National Oceanic and Atmospheric Administration, Sandia National Laboratories, San Jose State University, and the Bay Area Air Quality Management District. The last of these, the BAAQMD, conducted the prior study that found lower amounts of methane.

Lead photo: Researchers Seongeun Jeong (left) and Marc Fischer (right). Credit: Marilyn Chung/Berkeley Lab