Methane emissions higher than thought across much of US

University of California-Santa Barbara news release: After taking a rented camper outfitted with special equipment to measure methane on a cross-continent drive, a UC Santa Barbara scientist has found that methane emissions across large parts of the U.S. are higher than currently known, confirming what other more local studies have found. Their research is published in the journal Atmospheric Environment.

Methane is a potent greenhouse gas, stronger than carbon dioxide on a 20-year timescale, according to the Intergovernmental Panel on Climate Change, though on a century timescale, carbon dioxide is far stronger. "This research suggests significant benefits to slowing climate change could result from reducing industrial methane emissions in parallel with efforts on carbon dioxide," said Ira Leifer, a researcher with UCSB's Marine Science Institute.

Leifer was joined by two UCSB undergraduate students on the road trip from Los Angeles to Florida, taking a primarily southern route through Arizona, New Mexico, Texas, Louisiana, and along the Gulf of Mexico. They used specialized instrumentation, a gas chromatograph, to measure methane. The device was mounted in the RV, with an air ram on the roof that collected air samples from in front of the vehicle.

"We tried to pass through urban areas during nighttime hours, to avoid being stuck in traffic and sampling mostly exhaust fumes," Leifer said. "Someone was always monitoring the chromatograph, and when we would see a strong signal, we would look to see what potential sources were in the area, and modify the survey to investigate and, if possible, circumnavigate potential sources."

...Previous methane studies have focused primarily on large-scale airborne data, which were challenging to separate from local sources, according to Leifer. In fact, clear identification of individual sources often could not be conducted, requiring computer models and other surface measurements....

Cross-country data superimposed over satellite data from SCIAMACHY and from GOSAT. Satellite data shows positive methane anomalies for the southern U.S. are centered on eastern Texas. From the UC-Santa Barbara website