Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall. 

On our show, we talk a lot about how to reduce our carbon dioxide, or CO2, emissions. But some scientists are developing another approach to climate change — techniques to remove CO2 from the atmosphere.  

Here to tell us more are Isha Chawla and Fatima Husain from our Possibly team. Welcome, Isha and Fatima!

Isha Chawla: Hi, Megan!

Fatima Husain: Hello! 

Megan Hall: Okay, first things first. Why do we need to remove carbon dioxide from the atmosphere? Shouldn’t we be focused on using renewable energy and driving electric cars?

Isha Chawla: Well, reducing our carbon emissions as much as possible is definitely the first priority. 

Fatima Husain: But there are some sectors, like aviation, or cement and steel production, that are really hard to decarbonize.

Isha Chawla: On top of that, we’ve added and continue to add a LOT of carbon dioxide to our atmosphere. 

Fatima Husain: So it is likely we will need to find a way to take some of it back out to prevent the more extreme effects of climate change.

Megan Hall: But, is that really possible? How do you remove carbon dioxide from the sky? 

Isha Chawla: It is possible, but these carbon removal methods are still in the early stages of development. To get a sense of the ways scientists are trying to do this, we spoke with Dr. Galen McKinley.

Dr. Galen McKinley: I'm Professor of Earth and Environmental Science at Columbia University and the Lamont Doherty Earth Observatory.

Isha Chawla: She told us there are many different ways to remove carbon dioxide from the air. Some are pretty simple— like growing trees. Although if you have listened to our show before you know even that isn’t as easy as it sounds.

Fatima Husain: Other ways can get pretty complicated. But for now, let's focus on some of the technological solutions in use and in development today.

Isha Chawla: One of the most popular CO2 removal strategies uses chemistry to pull carbon dioxide out of the air. It’s called Direct Air Capture and Storage.

Megan: How does that work? 

Fatima: Basically, it involves pulling air over special solutions that separate out carbon dioxide, and then burying that CO2 deep underground. Galen says—

Dr. Galen McKinley: The challenge is that could require a lot of energy.

Isha Chawla: It’s also very expensive. Some estimates price removing a single ton of CO2 at $200!

Megan: How much would it cost to make a dent in this problem?

Fatima: Well, we emit about 40 billion tons of carbon dioxide in the atmosphere every year. Do you have $8 or so trillion dollars to spare, by chance? 

Megan Hall: Woah, I definitely don’t! Are there any more affordable ways to remove that carbon? 

Isha Chawla: Galen says there’s another technique called bioenergy with carbon capture and storage, or BECCS for short.

Megan Hall: And how does that work? 

Isha Chawla: So, the idea is you grow a bunch of plants, which suck up the carbon in our atmosphere today. And then you burn those plants to create energy, like electricity.

Megan Hall: But doesn’t that just release carbon into the air? 

Fatima Husain: The difference is—

Dr. Galen McKinley: Instead of being burned and re-emitted to the atmosphere,we capture the carbon and put it in the ground. 

Isha Chawla: So this generates energy AND removes CO2 from the air. 

Megan Hall: Wow! That’s interesting! Is this a realistic solution?

Fatima Husain: Not yet. It takes a lot of land to grow plants to make those biofuels and we need that space for other things— like forests and growing food. 

Isha Chawla: Megan, the gist is that none of these carbon removal methods are ready for prime time. But a lot of scientists think we should be researching them much more than we are already.

Fatima Husain: Because we’re going to need every tool we can find to combat the worst effects of climate change. 

Megan Hall: Got it. Thanks, Isha and Fatima! 

That’s it for today. For more information, or to ask a question about the way you recycle, use energy, or make any other choice that affects the planet, go to the public’s radio dot org slash possibly. Or subscribe to us wherever you get your podcasts. 

Possibly is a co-production of the Institute at Brown for Environment and Society, Brown’s Climate Solutions Initiative, and the Public’s Radio.