Jennifer Wilcox: How Can We Remove CO2 From The Atmosphere? Will We Do It In Time?

Jun 7, 2019
Originally published on June 10, 2019 10:01 am

Part 2 of the TED Radio Hour episode Climate Crisis.

About Jennifer Wilcox's TED Talk

To slow climate change, we need to lower emissions and remove carbon from the atmosphere. Chemical engineer Jennifer Wilcox says the technology is there, and we need to scale it.

About Jennifer Wilcox

Jennifer Wilcox has a master's degree in physical chemistry and a doctorate in chemical engineering from the University of Arizona. She is a professor of chemical engineering at Worcester Polytechnic Institute.

Wilcox's research focuses on how energy technologies can be used to address the environment. Her work develops both mitigation and adaptation strategies to minimize negative climate impacts associated with fossil fuels.

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On the show today, ideas about the Climate Crisis. So you've probably heard that the amount of carbon in our atmosphere is already at an unprecedented level - 400 parts per million and rising.

JENNIFER WILCOX: So 400 parts per million means that for every million particles of air, 400 of them are carbon dioxide.

RAZ: This is chemical engineer Jennifer Wilcox.

WILCOX: And that's actually a really dilute system. If we look at the exhaust of a point source like coal-fired power plant, it's 300...

RAZ: OK, so terms like dilute systems and exhaust of a point source - they're a little hard to wrap your head around. But 400 parts per million is a really important number because that's the point that scientists call the carbon threshold, where the climate cycle is thrown off balance. And it's a number that a lot of people are talking about.


UNIDENTIFIED REPORTER #1: Have now peaked at over 400 parts per million.

UNIDENTIFIED REPORTER #2: 403 parts per million.

UNIDENTIFIED REPORTER #3: 403.3 parts per million last year.

UNIDENTIFIED REPORTER #4: 415 parts per million.

UNIDENTIFIED REPORTER #5: 415 parts per million on Friday, it looks like, from the...

RAZ: I was watching a congressional hearing a couple weeks ago.


JOHN KERRY: That we now know that definitively at no point during the past 800,000 years has atmospheric CO2 been as high as it is today.

RAZ: And former Secretary of State John Kerry was testifying about climate change. And mentioned this number...


UNIDENTIFIED PERSON: Let me ask you this...

RAZ: ...400 parts per million.



UNIDENTIFIED PERSON: ...What's the consensus on parts per million of CO2 in the atmosphere?

KERRY: About 406 today.


RAZ: And a member of Congress, you know, questions his credentials.


UNIDENTIFIED PERSON: ...Appropriate that somebody with a pseudo science degree is here pushing pseudo science.

KERRY: Are you serious? I mean, this is really...


KERRY: ...A serious happening here.


RAZ: So, you know, you say that there are 400 parts per million in the atmosphere today.


RAZ: Well, you know, there have been times in - you know, in the history of the Earth where there were 800 parts per million. And, you know, Secretary Kerry responded by saying but never have humans been on planet Earth.


KERRY: There weren't human beings. I mean, that was a different world, folks. We didn't have...


KERRY: Seven billion people.

UNIDENTIFIED PERSON: So how'd it to get to...

RAZ: And that's the big difference.

WILCOX: That's right.

RAZ: So just - I just want to sort of put that into context. So when we talk about 400 parts per million today, it seems like a small number - right? - when you think of a million molecules. And just 400 of those molecules are carbon dioxide.

WILCOX: That's right. But the other thing you should keep in mind, too, is it's not just carbon dioxide. You know, there's other molecules like methane and water vapor that also can impact the greenhouse effect. So right now we're at a point where the natural systems are not able to uptake all of that CO2. And there's now extremely strong evidence that there are correlations between these - this 400 or 410 parts per million in the atmosphere today and the warming of the planet that we're experiencing. So the options we have now are no longer just plain, old mitigation. In order to make an impact, we also have to do the removal piece.


RAZ: OK, so just to be clear, you're talking about removing carbon from the atmosphere, as much of it as we can, to help get that number down to safer levels.


RAZ: And then the other option is to stop emitting carbon at all?

WILCOX: Absolutely. But I would argue they're not either-or options. I think that now we're at a stage where the pressure's on. And we have to, you know, do both.


RAZ: When we come back in just a moment, Jennifer Wilcox explains how we can pull CO2 out of the air. On the show today, ideas about addressing the Climate Crisis. Stay with us. I'm Guy Raz. And you're listening to the TED Radio Hour from NPR.


RAZ: It's the TED Radio Hour from NPR. I'm Guy Raz. And on the show today - ideas about the climate crisis. And we were just hearing from chemical engineer Jennifer Wilcox about removing carbon from the atmosphere and why just curbing emissions is not enough.

We have to stop emitting CO2. But even if we stop emitting CO2, we still have to remove it from the atmosphere to prevent catastrophic warming.

WILCOX: That's exactly right.

RAZ: OK, so how do you - how do we even start? I mean, first of all, don't trees do that? I mean, couldn't we just plant a lot more trees and forests around the world, and wouldn't that solve the problem?

WILCOX: No, planting trees is great. We need to absolutely do that. Aforestation or planting trees on land that didn't otherwise have trees, reforestation or even restoration of forests - all of that is good. And we're going to need to do that to some extent, but even that is not going to be enough.

RAZ: Because trees cannot possibly pull enough carbon out of the atmosphere that we need to pull out.

WILCOX: Exactly, not on the scale that we need to. And so these are the different options we have. But in my view, the portfolio of solutions today involve both avoiding CO2 and the removal of CO2 from the atmosphere.

RAZ: So when you talk about removing CO2 from the atmosphere, I mean, are you talking about, like, a giant air purifier, like, the kind you might have in your home but, like, an industrial-strength one?

WILCOX: Yeah, so I'll give you an example. If you think about how your water purification happens, in a Brita filter, say, you know, you have a charcoal filter that processes your water. And that filtration process captures all of the contaminants in your water so that your water comes out, you know, cleaner. So in a similar way, we design large contactors - these units that have a high surface area. And those contactors are filled with materials, and those materials have chemicals inside them that actually react with CO2 selectively. And then those contactors would, essentially, hold onto that CO2 until you are at a stage in that process where you can actually use the CO2 as a feedstock for a chemical process, or maybe you inject it back into the Earth.

RAZ: Because we know that a lot - most of the carbon that exists on planet Earth is actually sequestered in soil, in permafrost in the Arctic, in the oceans.

WILCOX: That's exactly right. But the chemical process is really not that different from how a water filtration system would work to purify water. But in this case, we're purifying air, and the contaminant is CO2.

RAZ: When can we start to deploy? I mean, you know, let's say we had all the money that we needed now, could we deploy this technology now?

WILCOX: Absolutely. So the technology is absolutely ready. These things are happening today. The question is, how can we increase the scale at which they're happening?

RAZ: Here's more from Jennifer Wilcox on the TED stage.


WILCOX: There's a company today, a commercial scale company, that can do this as low as $600 a ton. There are several other companies that are developing technologies that can do this even cheaper than that. One is called Carbon Engineering. They're based out of Canada. They use a liquid-based approach for separation. They have a clever approach that allows them to co-capture the CO2 from the air and the CO2 that they generate from burning the natural gas. And so by doing this, they offset excess pollution, and they reduce costs. So the companies that are developing these technologies are actually interested in taking the CO2 and making something useful out of it - a marketable product. It could be liquid fuels, plastics or even synthetic gravel. And don't get me wrong, these carbon markets are great, but these are not large enough to solve our climate crisis. We also need to be willing to invest as a global society. We could have all of the clever thinking and technology in the world, but it's not going to be enough in order for this technology to have a significant impact on climate. We really need regulation. We need subsidies, taxes on carbon. What will be required is that for carbon-neutral, carbon-negative paths to be affordable for the majority of society in order to impact climate.


RAZ: Jennifer, why do you think that there's a disconnect between what you know and what many scientists know and what the public doesn't seem to really worry about all that much?

WILCOX: That's a good question. I think that part of this is because CO2 - it's a pollutant. But, you know, we know that when you emit soot in the atmosphere, you don't get to see the sunset very well. It affects our day. And so I think with this, you can't see CO2. If it smelled, maybe it would be - maybe we would be more - you know, or if it was in our face every day, interrupting our view, that would be one thing. But it's difficult because it doesn't have any of these negative characteristics. But yet, we know now, with pretty high certainty, that these increased levels of CO2 directly correlate to the warming of our planet. But I think because it's just - it's not as dire as some of these other pollutants in the short term in our day-to-day lives that we tend to just look the other way.

RAZ: Do you think the goal of reaching net zero emissions is realistic and even attainable?

WILCOX: I think it's technically - you know, and technologically, it's absolutely realistic, and it is doable. But I think if our governments fail to act on helping to subsidize and support these efforts, it's not going to be feasible.


RAZ: That's Jennifer Wilcox. She's a professor at Worcester Polytechnic Institute. You can see Jennifer's full talk at

(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.