Gas stoves are contributing more to global warming than previously thought because of constant tiny methane leaks while they’re off, a new study found. The same study that tested emissions around stoves in homes raised new concerns about indoor air quality and health because of levels of nitrogen oxides measured. “They’re constantly bleeding a little bit of methane into the atmosphere all the time,” said the study’s co-author Rob Jackson, a Stanford University climate scientist. That methane is on top of the 6.8 million tons of carbon dioxide that gas stoves emit into the air when they are in use and the gas is burned, the study said.