California methane leak is largest in US history

Los Angeles Times : A massive leak of natural gas from an underground storage facility in California’s Aliso Canyon has raised concerns over leak detection efforts and the potential adverse effects of leaks on climate change. First detected by the Southern California Gas Co on 23 October last year, the leak spewed gas into the atmosphere over a period of some 112 days, until it was finally plugged on 18 February. To gauge the amount of gas being released, Stephen Conley of the University of California, Davis, and colleagues used an airplane equipped with sensors to make 13 flights through the invisible plume, each flight consisting of multiple passes at varying heights. They discovered that over the leak’s nearly four-month duration, the well released about 97 100 tons of methane and 7300 tons of ethane. Methane is a much more potent greenhouse gas than carbon dioxide and is a major contributor to global warming. A lesson learned from this recent disaster, says Conley, is the importance of rapid response in detecting and plugging such leaks.