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Is sucking carbon from the air the key to stop climate change? Some scientists say so


Scientists from around the world released a major report this month on how to stop climate change. For the first time, they found that getting rid of fossil fuels may not be enough. Carbon emissions may also need to be vacuumed out of the air. The idea is controversial.

Here to explain why is Lauren Sommer from our climate team. Hey there, Lauren.


KELLY: Start with the why. Why do scientists think this is going to be necessary to vacuum or soak up carbon emissions?

SOMMER: It's because global emissions need to fall really fast. Basically, the world needs to get to net zero emissions by mid-century. You know, that's to avoid things like extreme sea level rise and much more dangerous heat waves and storms.

But some sources of emissions are trickier than others to get rid of, like farming, for example. It releases emissions from using fertilizer and disturbing the soil. And by mid-century, you know, a technology for carbon-free airplanes and ships may not be widespread yet.

KELLY: I see. OK. So because those sources of emissions aren't likely to be eliminated in the near term, they need to find a new way to pull them out of the atmosphere.

SOMMER: Yeah, exactly. Because you can kind of think of the atmosphere like a bathtub. That's how Katherine Calvin, senior climate adviser at NASA, describes it. The bathtub is already too full, and adding more emissions is like leaving the faucet on.

KATHERINE CALVIN: If you want to stop the water level from going up, you either need to turn off the faucet or scoop out as much water as you put in. The same is true of climate. If you want to stop temperature from rising, you either need to stop carbon dioxide going into the system or scoop out as much as you put in.

KELLY: OK, so scoop out, vacuum up. How exactly would this work? How do you do it?

SOMMER: Yeah, there are a few ways. We're already surrounded by really powerful carbon sponges, and that's plants. You know, restoring forests and wetlands and mangroves can help soak up a lot of carbon. But the trick is you have to protect those ecosystems so the carbon dioxide stays locked in there.

And then another way relies on new technology to create giant vacuums, basically. There are these huge machines that suck in air and filter out the carbon dioxide so it can be stored underground in geologic formations.

KELLY: That sounds like a huge project and also a really expensive project. How feasible is that, these giant vacuums?

SOMMER: Yes. It's still unproven, so that means it's expensive, and it also needs a lot of energy. And then some climate activists also worry that, you know, focusing on that technology, on carbon removal distracts from the need to cut back on fossil fuel emissions now. It's kind of like a get-out-of-jail-free card for climate change. That's how Genevieve Guenther, the founder of the climate advocacy group End Climate Silence, describes it.

GENEVIEVE GUENTHER: This is influencing many industrial countries to just sort of, you know, kick the can down the road and make it seem as if we don't need to act urgently and unequivocally right now because later, there will be this technology.

KELLY: So Lauren, given all these issues, do these carbon vacuums sounds like they will ever be a central strategy, a main strategy to fight climate change?

SOMMER: Yeah, probably not the main strategy. You know, the major road map that just came out from the Intergovernmental Panel on Climate Change found that that sort of removal technology will be a small piece of the puzzle. The most crucial thing is to rapidly reduce emissions by getting off coal and natural gas and switching to renewable energy like solar and wind. And it's kind of gotten to the point, though, that time is running so short. You know, tackling climate change requires every strategy in the book.

KELLY: Thank you, Lauren.

SOMMER: Thanks.

KELLY: That's Lauren Sommer from NPR's climate team.

(SOUNDBITE OF THE BAD PLUS' "AVAIL") Transcript provided by NPR, Copyright NPR.

Lauren Sommer covers climate change for NPR's Science Desk, from the scientists on the front lines of documenting the warming climate to the way those changes are reshaping communities and ecosystems around the world.