In its 2018 report, the U.N. Intergovernmental Panel on Climate Change said that our current efforts just to lower carbon emissions aren’t enough. To prevent the worst of climate change, the world needs to remove carbon from the atmosphere in large quantities. The idea of removing it from the air at any kind of scale requires the proper technology, money, political cooperation, all of which pose unique—and seemingly insurmountable—challenges.
On Friday’s episode of What Next: TBD, I spoke with Clive Thompson, journalist and author of Coders: The Making of a New Tribe and the Remaking of the World, about the race to suck carbon out of the air. Our conversation has been edited and condensed for clarity.
Lizzie O’Leary: You recently wrote a story, which ran in Mother Jones, about direct air carbon capture, a new technology that might be helpful in addressing the climate crisis. What is DAC?
Clive Thompson: Direct air carbon capture is basically the art and science of extracting CO2 from the air. You create a machine that uses a chemical process to bind CO2 and turn it into something that you can then store somewhere. Maybe you shove it really deep in the ground so it’s gone, maybe you turn it into something else that you can use.
Who is actually making the DAC technology?
So at the high end, you have a company like Carbon Engineering, which is up in Canada. And the way it works is that they have a big machine that’s the size of a building, with a huge fan on top of it that sucks air in and blows it down into a pool of liquid sorbent. Then it reacts. Once there’s lots of CO2 in the sorbent, they use a process that requires temperatures of hundreds and hundreds of degrees to turn it into CO2 that can be stored as a pressurized gas. The downside is that a lot of energy is needed to run that machine. That’s one model.
What’s the other model?
The other model is to have much smaller machines that you could tuck anywhere that use a lot less energy, which is great, but they also don’t suck quite as much CO2 out of the air. Klaus Lackner [a professor at Arizona State University] created a tree of these discs that stands 30 feet high, and the wind just blows air past it. That reacts with the sorbent inside these discs, and then once every hour or so when the discs are full of CO2, it collapses down almost like an umbrella, and squeezes it out with a little bit of heat. They’re so low-energy that he imagines you might need tens of millions of them, but you could put them literally anywhere.
Direct air capture sounds very sci-fi. When we’re thinking about it in the public policy arena, it seems like there are two big questions: What would it take scientifically to do this at scale, and what would it take practically and politically?
What you’d need to really do this is an almost wartime mobilization of resources. And, there are lots and lots of choke points. You’d need tons of that sorbent chemical. You’d need to figure out a lot of issues: Where do you put all that carbon? What do you do with that stuff? But could you get it out of the sky, could you do that at scale? Yes. I think you could.
On a practical level, even saying there was the global will for this, it seems like there are three big structural hurdles: cost, transportation and storage. How much does it cost to do this?
The estimate that I most often heard is that right now the cheapest they can do is about $500 per ton of CO2. Everyone who looks at this field basically says that that is way too much. That is way too expensive to be able to do what we need to do. Because the IPCC was talking about removing 10 gigatons a year, which is billions of tons. So at 500 per ton, you’re talking about trillions and trillions of dollars.
So, what price does it need to get to? No one really knows. But if it were around $100 per ton, then there starts to be a more of a market for this stuff. If you got it down to $50 or $10 a ton, then you’re really talking.
There’s another issue besides cost. How can you move the carbon dioxide once you’ve got it?
These machines could be anywhere. They could be in Boston, they could be out in the desert in Arizona, they could be all over the place, and you need to have a pipeline. And piping CO2 is really not easy because it is a highly pressurized gas.
If you have a leak, it’s really bad stuff. It erupts with high pressure, it is an asphyxiating gas so it would kill people, and worse of all it hangs low to the ground. It’s heavier than air if it’s in a dense quantity.
You’re not really selling direct air capture to me here.
Let me make it a little bit worse by pointing out that traditionally pipelines get run through Indigenous lands. So yeah, am I selling it? No. My goal with this story was to paint a very realistic picture of the enormous opportunity but the enormous challenge here. I’m not saying it would be impossible to do that, and if it became like “we have no other option,” then I guess we would bite the bullet and figure it out. But it’s something you’d want to really think hard and plan for if you’re going to do it, which is a good reason to think about the problems now.
The other level of this story that takes it to another bananas head-scratching place is that it seems from your reporting that the only players who could afford to do this, who have a really vested interest in doing this, are Big Oil companies.
This is the issue that really alarms a lot of environmentalists about direct air capture. Nearly all of the projects that I’ve been telling you about here are all being developed hand in glove with oil and gas companies, fossil fuel companies. Why is that? Well, the people who understand how to build things at scale that have to do with energy and how to move gases around are the oil and gas companies. They’ve got decades of experience in this. So they’re the first obvious partners.
What do you do with that CO2 when you’ve captured it? We talked about shoving it in the ground to get rid of it. The problem is that in the short run—and by the short run I mean a decade or more—there’s really no one who’s planning to shove that in the ground. What all of these projects are doing is working with oil and gas companies to do something that creates a market for the reuse of that CO2.
There is a market right now for CO2, but it’s niche. There’s a company in Texas, for example, that uses it to get the last drops of oil and gas out of nearly empty wells. It’s something other companies might adopt. And that brings us back to this question of environmentalists having to work with or rely on oil companies. Are some environmentalists able to say, “OK, this involves a deal with the devil but it gets us there”? Or is it just like, “No, that’s a nonstarter”?
Environmentalists are divided on this. Many of the environmentalists, I would say the majority of them, said to me, “We think this is a costly distraction. We think that all the money being put into developing direct air capture should just be put into scaling out renewables dramatically right now. Innovating on that front. That is how we decarbonize. We do it by just rapidly throwing everything we can at this. And we seal the oil and gas companies out of this process because they are just bad news.” These environmentalists argue that oil and gas companies just want this tech to exist as a get-out-of-jail-free card.
Because it helps them reduce their net emissions?
Yeah. It would become this way of saying, “Hey, we’re net neutral! We’re creating lots more emissions by selling lots of oil and gas, but we’re also shoving it in the ground.” Or even worse, they’ll develop this technology a little bit, but never get serious enough about it. This is what’s known as the moral hazard argument. If you start developing the technology, it takes the pressure off of society to decarbonize its energy production. If you think that there is a magic solution coming 10 or 20 years from now, then yeah, maybe it’s OK to keep burning oil and gas and maybe we don’t need to aggressively roll out solar and renewables.
The thing about direct air capture that is so fascinating is how complicated it is. Not in terms of the tech, but in terms of the moral and ethical equations around it.
Among other things, direct air capture would allow for a certain level of environmental and economic justice insofar as we’re now in a situation where parts of the Global South are rapidly trying to expand their economies, and to do that you need lots and lots of cheap energy right now. Those societies want to do what we did, which is to burn lots of oil and gas to get themselves as prosperous as possible as quickly as possible. So the progressive argument is that maybe it’s up to the developed countries that made this mess to work on direct air capture and clean up the problem for the countries that we have trod all over in the last 50 or 100 years.
Would doing direct air capture on a global scale be an admission of defeat?
Yeah, absolutely. It would be a complete admission of defeat insofar as it would be us saying to ourselves, “We couldn’t change the way we lived.” For decades we were unwilling to do that. We knew in the ’90s that we needed to work on decarbonizing the economy as rapidly as possible and rolling out renewables and we didn’t do it. We didn’t push for it. To the extent that a lot of citizens did push hard for it, they faced ferocious opposition from oil and gas companies and from many politicians who were absolutely in their pockets.
What do we know about how the oil companies are approaching these projects?
Several people said to me that one of the reasons why they are dubious of the motives of oil and gas companies is that none of them are really reorienting their spending habits around it. They’ve got R&D projects, but things only really change when you see what they do with their annual budgets. And with their annual budgets they’re still just drilling for oil.
Some people have said that the only way that we’re going to roll out million and millions of direct air capture machines and make it really cheap is if for the next 10 or 20 years we actually turn the CO2 back into liquid fuel and burn it again. When I say to them, “That sounds circular. Isn’t the point to get it out of the air and into the ground?” They’re like, “Well yes, but think of it this way. What we’d be doing is decarbonizing the internal combustion engine.” So, the idea is we can keep on using all these trucks and all these planes and cars that have internal combustion engines, but we would actually have net zero emissions or as low as possible emissions. But, it’s a leap of faith.
Do you have any faith that this is going anywhere?
The only faith I have is the faith that comes from seeing things like solar succeed. One of the reasons why solar got so good is governments gave some subsidies and that took leadership, and that was good. And then that incentivized a marketplace of solar creators to go, “Hey, we can make money with this!”
I definitely feel gloomy all the time because of the lack of political urgency amongst the folks who run things. I also know that sometimes things can be working better than we imagine in different pockets of innovation and marketplaces and policies. But I don’t hold out great hope.
Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.