A study finds tiny leaks from loose fittings added up to more emissions than when stoves were in use. The impact of U.S. gas stoves on climate change amounts to the same effect as a half-million cars.



An old saying says now we're cooking with gas, which means we're doing it fast and right. But the old saying is incompatible with climate change. Natural gas cooking faces scrutiny, and a study out today shows that gas stoves may leak climate-warming greenhouse gases even when the stove is turned off. Jeff Brady joins us from NPR's climate team. Hey there, Jeff.

JEFF BRADY, BYLINE: Hey. Good morning, Steve.

INSKEEP: You are apparently talking about the stove in my house. So what's going on here?

BRADY: Well, you know, it's not obvious why a gas stove that's off might leak. It's not obvious at first, but just stick with me a little bit here.


BRADY: Scientists at Stanford University measured emissions from gas stoves in 53 California homes. They were looking for methane; that's the main ingredient in natural gas. It's also a potent greenhouse gas. Researchers measured how much methane is leaked each time you turn the knob in that second before the gas lights on fire. They also measured how much unburned methane is released during cooking. And they measured how much methane is released when the stove is off. Stanford professor Rob Jackson says most of these leaks come from loose connections.

ROB JACKSON: Simply owning a natural gas stove and having natural gas pipes and fittings in your home leads to more emissions over 24 hours than the amount emitted while the burners are on.

BRADY: And Jackson says in this study, it didn't matter if the stove was old or new or what brand it was, the presence of leaks was consistent.

INSKEEP: Which is amazing. It means that I'm just kind of living with a lot of gas, even if I never cooked anything. But how big a problem is this in relation to climate?

BRADY: Well, you know, compared to something like coal-fired power plants, this is a relatively tiny amount of greenhouse gases. And there are no health risks here that - to speak of. But the U.S. has a goal of zeroing out greenhouse gas emissions by 2050. Jackson says if you add up the more than 40 million gas stoves in the U.S., the amount of leaked methane every year has about the same climate-warming effect as the carbon dioxide from a half million cars. Now, the EPA says buildings account for more than a tenth of the country's greenhouse gas emissions. That's why some climate activists want to switch to electric - want people to switch to electric stoves. That's part of a broader campaign to stop natural gas use in buildings. The thinking is that since Americans care about the cooking stove, changing that to cleaner electricity and, you know, then maybe bigger sources of emissions in homes may get switched, too, like the furnace, the water heater and clothes dryer

INSKEEP: How are natural gas utilities responding to these campaigns to get gas out of the house?

BRADY: This is an existential threat for gas utilities because energy modelers say it's hard to find cost-effective ways to reach net zero emissions if gas still gets burned in individual homes and offices. And those utilities, they're trying to find cleaner replacements, things like so-called renewable natural gas from agriculture and using hydrogen produced with renewable energy. Also, those utilities are getting laws passed to preserve their business. Twenty states now have laws on the books that prevent cities from banning gas hookups in new buildings, and that's been a trend as local governments try to meet their own climate targets in places like Seattle, Berkeley and New York.

INSKEEP: If you keep the gas stove, can you at least cut down on these leaks?

BRADY: Yeah. And really, all it takes is a wrench. Rob Jackson at Stanford says you can pull out your stove, check to make sure all the gas connections are nice and tight, and that'll at least reduce the leaks. But Jackson says he's among those concluding that the only way to ensure there are no leaks is to switch to an electric stove. And he says his research has convinced him it's time for him to do that.

INSKEEP: Jeff, your reporting is cooking with gas, as you would say.

BRADY: (Laughter) Thank you.

INSKEEP: NPR's Jeff Brady.

(SOUNDBITE OF EL MICHELS AFFAIR'S "C.R.E.A.M.") Transcript provided by NPR, Copyright NPR.