Nitrous oxide is the new chlorofluorocarbons. A study published today fingers N2O, aka laughing gas, as the most dangerous ozone-depleting gas in the air, Time reports. Nitrous oxide isn’t as dangerous as CFCs, but it’s incredibly common, emitted by everything from fertilizer to sewage treatment plants to cars. “Pretty soon, human-caused N2O emissions will be greater than all other ozone-depleting substances combined,” warned one atmospheric scientist.
CFCs have been all but eliminated thanks to the Montreal Protocol, but N20 isn’t covered by any agreement other than the widely skirted Kyoto Protocol. It’s in that agreement not as an ozone depleter but as a greenhouse gas—it’s 300 times more potent than CO2. “The question is how are we going to reduce these gases,” says the atmospheric scientist. “We need to bridge that gap between science and policy.”