Carrie Herzog was sitting at her desk in Montreal one day in early 2019, studying satellite images for signs of mud volcanoes. These geological oddities, common around the Caspian Sea, can belch greenhouse gases. Herzog’s job as a technician at GHGSat Inc. , a Canadian company that monitors emissions, is to identify individual pieces of the planet-warming puzzle. Her eye caught something strange on the edge of an arid, wind-scoured stretch of desert in Turkmenistan. Something that shouldn’t have been there. Stretching north from a clutch of industrial structures in the former Soviet republic were two jagged slashes more than three kilometers long, captured by the satellite’s imaging spectrometer, an instrument that allows scientists to identify gases based on how they reflect light. Surprised, Herzog summoned a colleague. Then their superiors directed the satellite to take a closer look on its next pass. Emissions-spotters at SRON, a space-science institute […]