US: Three months after the Southern California Gas Co. reported the massive leak in its Aliso Canyon gas field, near Los Angeles, scientist Rob Jackson of Stanford Woods Institute for the Environment has created a map that suggests, the well is still leaking gas and spreading it in the air.
The map shows an alarming level of methane compounds being disseminated in the Porter Ranch, the neighborhood where thousands of people have been displaced. The authorities are facing challenges in determining the location of the leak.
For creating the map, Rob Jackson and his colleagues took a tool they use regularly in their research–a very accurate laser-based methane detector–and spent a weekend sampling methane in Porter Ranch. The red line shows the path they drove around the neighborhood, and its height indicates the amount of methane measured.
As Jackson writes, in a post on Medium, they found a dramatic difference between the south and north parts of the neighborhood: the methane level was “an order of magnitude or more greater in the northwest corner of the neighborhood nearer the gas leak.” The gas field itself, from which the methane is spreading, is in the top-right corner of the image and behind the red wall of methane concentrations measured on the northern-most road they drove.
The well won’t be sealed until February, at the earliest, according to the Los Angeles Times. While driving around Porter Ranch, Jackson was surprised, he says, to find that sometimes it was hard to tell if the leak was happening at all. But, fifteen minute later, in the same place, if the wind changed, the air smelled strongly of gas.
Methane itself has no odor, but a smell is often added to mark its presence. Often called natural gas, methane is commonly used in stoves and for heating, but it’s a potent greenhouse gas, which lingers in the atmosphere for less time than carbon dioxide but is many times more effective at trapping heat. Over twenty years, for instance, methane’s global warming potential is 72 times greater than carbon dioxide.