Environmental News Network: The amount of methane in Earth’s atmosphere shot up in 2007, bringing to an end a period of about a decade in which atmospheric levels of the potent greenhouse gas were essentially stable, according to a team led by MIT researchers. Methane levels in the atmosphere have more than tripled since pre-industrial times, accounting for around one-fifth of the human contribution to greenhouse gas-driven global warming. Until recently, the leveling off of methane levels had suggested that the …