Methane from Siberian permafrost could speed warming , raise costs . Economic models say that additional tab could hit $ 60 trillion . The gas is more potent than carbon dioxide in trapping heat . Comment:
Methane from Siberian permafrost could speed warming , raise costs . Economic models say that additional tab could hit $ 60 trillion . The gas is more potent than carbon dioxide in trapping heat . The study is a warning but `` not doom and gloom , '' author says .