Podcast Episode 1.38

Ocean-Based Carbon Dioxide Removal and Geoengineering with Wil Burns

Earth’s oceans play a key role in slowing climate change, absorbing nearly a third of anthropogenic CO2 emissions.

And they could, potentially, absorb more.

In this episode, Climate Now explores developing methods to enhance ocean-based carbon dioxide removal. What do we know about each technique, and what are the associated risks?

Learn more in our conversation with Dr. Wil Burns, visiting professor at Northwestern University’s Environmental Policy and Culture Program and emeritus co-founding director of the Institute for Carbon Removal Law and Policy at American University.


Wil Burns
Visiting Professor at Northwestern University


Wil Burns

Visiting Professor at Northwestern University

Wil Burns is a visiting professor at Northwestern University’s Environmental Policy and Culture Program and emeritus co-founding director of the Institute for Carbon Removal Law & Policy at American University.

Dr. Burns is also a Senior Research Fellow for the Centre for International Governance Innovation (CIGI) and served as the Director of the Energy Policy & Climate program at The Johns Hopkins University.

Hosted By:

James Lawler
Climate Now Host


James Lawler

Climate Now Host
James Lawler is the founder of Climate Now. James started Climate Now as a way to learn about climate change and our energy system. Climate Now’s mission is to distill and communicate the science of our changing climate, the technologies that could help us avoid a climate crisis, and the economic and policy pathways to achieve net zero emissions globally. James is also the founder of Osmosis Films, a creative studio.


James Lawler: I’m James Lawler and you are listening to Climate Now.  In our video series, we’ve explored different forms of carbon dioxide removal, abbreviated CDR. We’ve looked into costs and benefits of using trees to sequester carbon, how carbon capture and storage works with Direct Air Capture or point source scrubbing technology. But what about the oceans? Covering 71% of Earth’s surface, Oceans are already key to regulating our carbon dioxide emissions. Without them, we would be much, much, much worse off. So we wanted to learn more about the ocean’s potential to absorb more carbon dioxide than it already does.

To speak with us about ocean-based carbon dioxide removal, we reached out to Dr. Wil Burns, who is a visiting professor at Northwestern University’s Environmental Policy and Culture Program, and emeritus co-founding director of the Institute for Carbon Removal Law & Policy at American University.

Wil, welcome to Climate Now, it’s a pleasure to have you on the show.

[00:01:01] Wil Burns:  Thanks for inviting me, James.

James Lawler: So tell us how did you get to where you are today in your career? How did you come to be an expert in ocean-based carbon dioxide removal?

[00:01:10] Wil Burns: As is often the case, it was serendipitous. I was working on climate issues since the 1980s, and in the last decade, I had read a little about climate geoengineering, which includes carbon removal, and I thought it would be an interesting topic for my students, because it’s kind of a pastiche of technology, and science and law and ethics and politics. I moved to run the energy policy and climate program at Johns Hopkins in DC, and one day I got a call from a receptionist at the CIA. They wanted to link me to somebody in the CIA that wanted to talk to me. Right. Which is never fun.

James Lawler: That’s a fun call.

[00:01:54] Wil Burns:  Yeah, but I took the call and it turned out that the CIA was funding the National Academies of Sciences first report on climate geo-engineering.

The academy was concerned that some countries or private groups might try to weaponize some of these approaches. And so they wanted to learn more about it.

[00:02:12] James Lawler: Can I pause you.? Just a question. So the funding for the study of carbon dioxide removal was motivated by a concern about weaponization?

[00:02:20] Wil Burns: Well, when we were looking at these issues early on and people talked about climate geoengineering, most of what they were looking at was the other kind of interventions, which are called solar radiation management. And so, solar radiation management includes things like putting large amounts of sulfates into the sky to try to make the skies more reflective and reflect more incoming radiation back to space, but it can alter precipitation patterns, it can deplete the ozone layer, things of that nature. And so the CIA was concerned that people might try to use it for weather modification, for example, on a very large scale. And so their focus at the time wasn’t really carbon removal, but this other kind of geoengineering.

James Lawler: Got it. Sorry I cut you off.

[00:03:10] Wil Burns: Yeah. That’s okay. So once we realized that it was important enough for the CIA and the NAS to be looking at it, we started thinking maybe we should look at this in a more organized institutional fashion. So, I had a colleague at American Simon Nicholson, and we decided to form a think tank to start looking at geoengineering, which was called the Forum for Climate Engineering Assessment.

We ultimately grew and split into two parts, one institute which focuses on these solar radiation management approaches, and then the Institute, which looks at carbon removal approaches, which is the other side of the coin. So instead of trying to reflect more solar radiation back to space to exert a cooling impact, carbon removal approach is seek to remove carbon dioxide from the atmosphere to reduce radiative forcing in the trapping of outgoing greenhouse gases, which also can exert a cooling impact.

James Lawler: And so at the Institute for Carbon Removal Law and Policy today, what are your core areas of focus?

[00:04:11] Wil Burns: Mostly what we do is look at social science aspects. So I’m a international environmental law person by training in Simon is an international environmental politics person by training. And so we thought we might be able to contribute. So what we do is we look at issues such as governance, how we structure public deliberation, how we acknowledge the kind of trade-offs that may occur in these technologies.

And how do we assess the integrity of the claims that are being made both in the private sector and the public sector in terms of carbon.

[00:04:43] James Lawler: Excellent. You know, many people who follow climate, have heard or understand that the oceans absorb carbon dioxide, on their own, this has been happening for eons and will continue to happen. What I’d love for you to tell us is how much CO2 do the oceans absorb? How does it happen? And if the oceans can absorb so much CO2, why are we worried about the buildup of greenhouse gases?

[00:05:07] Wil Burns: Yeah. All good questions. So first of all, how they absorb it. So it’s based on the pressure differential between the CO2 that’s in the atmosphere and the CO2 that is in the oceans.

So as the amount of CO2 has risen in the atmosphere, right – it’s gone up from about 286 parts per million (ppm) in pre-industrial times to about 410ppm now- as that buildup has occurred, it’s exerted more pressure downward of that CO2, and it’s been driven into the oceans. And so the oceans have become a larger what we call sink, right, a reservoir for CO2. We’re not entirely certain what that sink is at this point, but we have a pretty good idea. We know there’s billions of tons of the CO2 that we admitted into the atmosphere every year through anthropogenic human-based sources that are ultimately taken up into the oceans. Most scientists estimate that it’s around 25% of all of those emissions and then another 25% or so end up in terrestrial sources, such as soils and trees. Okay. Now the last question, you know, well then why can’t we party like it’s 1999, right? They’ll just keep taking up CO2. Well, the good news is that the CO2 that’s taken up is really important. If the oceans weren’t serving as a sink for CO2, atmospheric concentrations of CO2 would be a lot higher, maybe about 50 to 60 parts per million, and that makes a big difference. We’re at 410, that means we’d be more at 460, 470. That’s the threshold above which temperatures are at least 1.5 degrees Celsius above pre-industrial levels. And that’s one of the goals of Paris, right? Is to try to hold it to 1.5. And we’re already seeing serious manifestations of climate change at about 1.1 degrees. When you get to 1.5 and beyond things get really serious, right? So the oceans have done us a real favor.

The problem is that the oceans probably cannot continue to do this because of climate change itself. Climate change can denude the ability of oceans to hold CO2 in a number of ways. And we’re starting to see some of this. One of them is as the oceans warm solubility, the ability to hold gases, decreases, right? And we’re starting to see this in certain areas like the North Atlantic gyre, for example, where the increased warming of the oceans is decreasing solubility and the ability to absorb CO2.

[00:07:37] It can also alter circulation patterns and these circulation patterns ultimately take up CO2 and transport CO2. And so what we’re afraid of is that we’re going to see what’s called a positive feedback response to the system. Ultimately the warming of the oceans results in a reduction in the ability to hold CO2, more CO2 ends up in the atmosphere, which contributes to more warming, which the denudes, the ability of both the oceans and terrestrial sources like trees and soils to hold CO2 and the cycle continues and continues.

[00:08:14] James Lawler: So let’s turn now to those proposals. So there are a variety of proposals, technologies and ideas, some seeming more far-fetched than others.

So you’ve written or been coauthor on various articles and reports that sort of describe these. So I’m wondering if you could take us through the spectrum of these ocean-based CDR proposals and methods.

And if we could look at each one through a similar set of lenses. That is, what it is, what the concept is, how it works, feasibility, so how easily could we actually do this thing at a multi-gigaton scale? Right. That’s important. We don’t care if it’s just, you know, a couple of CO2 molecules, we need to gigatons of CO2.

And finally, what are some of the adverse consequences? Because I think with all of these proposals, there are trade-offs. I’m just going to name all of them, just to give listeners a sense of what we’re going to cover, and then we can maybe just go through each one in turn.

So we’re going to cover marine cloud brightening, very interesting; micro bubbles and foam; we’re going to talk about ocean iron fertilization; artificial upwelling, and downwelling; ocean alkalization or ocean liming; and blue carbon. So we’re going to try to get through all of these. So Wil, maybe we could start with marine cloud brightening. What does that mean? And how would we do that? How would it work?

[00:09:40] Wil Burns: Yeah. One thing I want to emphasize is that both Marine cloud brightening and the ocean bubbling approaches are not carbon dioxide removal approaches. They’re the other genre, this solar radiation management. Okay. So, in both cases, they’re trying to increase albedo or reflectivity to reduce the amount of incoming solar radiation.

So the first one, marine cloud brightening, it is a fascinating concept. So the idea is to seed low-lying maritime clouds with saltwater particles. And the idea is to increase the nucleation of those particles. It increases the water droplets in those clouds, at least in theory, it increases the total number of water droplets, which makes those clouds more reflective, right?

So as incoming solar radiation hits those clouds, because they are a more reflective surface, more of the incoming radiation glances back into space and is not trapped by greenhouse gases. So, researchers that have proposed this have said that one way that you might be able to do this is to develop this fleet – and this was a group of scientists in Scotland – a fleet of 1500 remote controlled GPS guided spray vessels that would just tool themselves around the ocean and spray saltwater into these clouds. And they concluded that those 1500 vessels, which we could develop for about a hundred million dollars a year, could offset the radiated forcing associated with doubling the concentrations of greenhouse gases from pre-industrial levels.

So up to about 560 or so. Okay. That’s at least the back of the envelope.

James Lawler:  So that’s really a stunning result. If that’s true.

[00:11:28] Wil Burns: If that could be the case, it could be amazing. Now the questions, as you said, first question is, do we think that’s true? Okay. The answer is we really don’t know. Any of you that work in the field of climate change science know that of all of the bedeviling factors that we look at in climate science, probably one of the most bedeviling if not the most bedeviling is clouds, right. And their interaction with climatic change, right.

That’s certainly true with this because here’s an approach that directly relies on clouds to save our bacon. Right. So, the studies over the years, and virtually all of them have been theoretical lab based sort of studies, right? – we have virtually no empirical research, no field research to look at for this – but what those studies have told us is that we clearly don’t know. They’ve been all over the place. Some of them have shown very little impact, some have shown dramatic impact. Some have shown that it resulted in a net darkening of the clouds, which could actually exacerbate climate change.

Right? So one of the things to emphasize is we don’t know at this point, and we clearly need a lot more research, including field research, to try to characterize this.

[00:12:41] James Lawler: I’m sorry, just to clarify. The group of Scottish scientists that published the paper that made, you know, that estimated, this effect, were they basing that off of any kind of bench science or any kind of more microcosmic results that could be extrapolated to that conclusion or was that sort of a purely theoretical assessment?

[00:13:02] Wil Burns: It was mostly a theoretical assessment and most of the studies since then have been the same. The other thing that we’re concerned about in this context are some of the risks associated with this, right. One risk is, if it’s successful, it’s going to make a lot of these ocean areas much cooler. Right. And that’s going to change, nutrient balances. It’s going to change upwelling equations and things like that for a lot of species, and that could potentially have adverse impacts and some of those systems, and it could change biogeochemical cycles because we’re contemplating doing this if it’s going to make a difference on a very large. Right. The other thing that we’re worried about is that it could change regional precipitation patterns and it could change them substantially in areas like the Amazon and areas of Africa.

And so these are areas where we’re extremely concerned about a potential reduction in precipitation, right? So the theme with a lot of these solar radiation approaches, including the one of putting lots of sulfur into the stratosphere, is that it could produce winners and losers. Right. And it may even be that on balance, one could make the argument that the world is better off from a standpoint of comparing business as usual scenarios of climate change by utilizing these. But the question is, is it equitable on the “losers”?

[00:14:25] James Lawler: One has to balance that question with the question of, well, how equitable is, you know, are the effects that we are experiencing from climate change in the first place, is that better or worse?

[00:14:38] Wil Burns: That’s absolutely right. And whether the choice is unchecked business as usual or interventions, or could we far more aggressively, you know, mitigate our emissions and reduce the need, or eliminate the need to use these risky approaches?

[00:14:55] James Lawler: Fascinating. So let’s move to the next one, which is also, you know, an SRM or solar radiation management technology, which is the micro-bubbles and foam.

[00:15:03] Wil Burns: Yeah. So there was a professor in the 1970s at Harvard who proposed this. And essentially the idea is to create huge amounts of bubbles on the world’s ocean surfaces by using pumps or systems suspended from boats or so forth. And if you increase the bubbles on the ocean surfaces, the ocean becomes brighter, and again, it reflects incoming solar radiation back to space.

[00:15:29] James Lawler: So this is sort of a bubble bath on a global scale?

Wil Burns: That’s right.

James Lawler: Okay. And why might we not want to do that?

[00:15:37] Wil Burns: Yeah. Well, first of all, we don’t know if it’ll work. Again, we’re largely in the theoretical and the studies are all over the place, though I have to say some of the more recent studies tend to lean to say that it wouldn’t have much impact on insolation, which is how much incoming solar radiation ultimately gets introduced to earth. It also has risks. Again, you’re cooling ocean surfaces. You may increase the efficiency of CO2 uptake, which could exacerbate ocean acidification. Also, the bubbles tend to be pretty evanescent. They don’t last for long. And so people have said you probably have to use chemicals like surfactants to try to increase the life of those bubbles. Well, some of those chemicals could have impacts in sensitive ocean ecosystems. So you’d need all kinds of characterization. Right.

[00:16:26] James Lawler: Okay. So ocean iron fertilization, here we move into the carbon dioxide removal side of the ledger. What is this?

[00:16:34] Wil Burns: So one of the things I want to say at the outset about ocean fertilization that makes it interesting in the realm of these things that we’re talking about is that it is one of the few where we’ve actually done a fair amount of field research.

So we have some results to actually look at this point. Okay. So there’s been 14 field research experiments to date in this context. Right. And we’ll talk a little bit as we get a little lower about, well, some of the results. So the idea behind ocean iron fertilization is that you have these plants in the ocean that we know of as plankton, right? And plankton, as is true with trees in terrestrial surfaces, take up CO2. So they convert inorganic carbon to organic carbon, and they use it in photosynthetic processes. And despite the fact that phytoplankton are only 1% of our biomass, they’re responsible for 50% of the photosynthesis that occurs on earth.

So they take up huge amounts of CO2. Now, most of that CO2 that the phytoplankton take up is almost immediately released back at surface. Zooplankton consume them because the, you know, phytoplankton are a gigantic sushi bar, and higher order species eat the zooplankton, the CO2 gets released. But there’s a small percentage of the CO2 that stays with the phytoplankton when they die, and they drop below the photic layer, the light layer, to the bottom of the oceans. And there in the sediments, that CO2 can be stored for thousands of years. And we call this the biological pump, right? Same thing happened with their feces. So you get lots of CO2 in phytoplankton poop that ends up at the bottom of the ocean and gets stored.

[00:18:17] Ocean iron fertilization proponents argue that there’s substantial areas of the oceans, about 20%, that have large amounts of critical macro nutrients for optimum phytoplankton growth, like nitrogen and phosphorus, but they lack a critical micronutrient and that micronutrient is iron. And what they’ve argued is that if you dumped a large amount of iron, in the form of ferrous sulfate, it’s essentially the same kind of iron that we take for anemia, into the oceans, especially in the Southern ocean where it’s particularly anemic, they argue, that you’d get mass proliferations of phytoplankton.

They take up a lot more CO2. And when they died, it would get sequestered. And in some of the early studies, lab-based studies, they said that we might be able to take up as much as 25% of all of the CO2 in the atmosphere through this process.

[00:19:15] James Lawler:  When you say that investigators have gone and believe that they’re areas of the oceans that are missing the critical nutrient of iron, have measurements been taken globally and have we actually identified sort of these iron light regions, or how crisply do we understand what the potential could be there.

[00:19:39] Wil Burns:  I have to say that there’s fairly good characterization. I think of some of the areas that are iron poor what has remained speculative And as we talk about these studies, we’ll see why, is how much phytoplankton production ultimately would occur as a result of putting more iron. If iron is clearly the limiter in this case.

[00:19:59] James Lawler: Can we get into those, some of those studies while we’re on the topic?

[00:20:03] Wil Burns: So, as I said, we’ve had these studies, they started in the last decade, and it was a combination. It was, kind of some Cowboys that just went out there and said, hey, let’s dump some iron, and maybe even get some carbon credits for it. And then some quite sober, responsible sort of university-based research consortiums. And most of them have gone out there and put a small amount of iron we’re talking about maybe a ton, per a couple of hundred kilometers of iron. Right. And then tried to see what happened. Was there, a proliferation of algae, phytoplankton production, did that ultimately sink and, you know, try to make some estimates based on that.  Of those 14 studies, only three of them really found much proliferation of phytoplankton.

Okay. A lot of the studies found that even in cases where there was proliferation, we saw what we talked about before, which was this gigantic sushi bar that attracted lots of predators. Right? And so the only way that you would get sequestration is if this phytoplankton has the CO2, when they drop below the photo clay or the light layer, and ultimately end up in the deep ocean, if it gets consumed at surface or re mineralizes before that photonic layer, the CO2 is going back into the atmosphere.

And virtually none of the studies found much either phytoplankton production or sinking below the photic layer. And so the early estimates of like, as much as 25% started to decline, and now we start hearing people say, well, maybe 5%, right? Some of the proponents argue a couple of things. They say, first of all, we need longer-term studies than we’ve had to really characterize this.

And second of all, if at the end of the day, we only got a gigaton from this, it would be part of a portfolio, right? Because what we acknowledge now is we’re not going to be able to get all the carbon removal with one magic bullet.

And there may be more research expeditions. There’s been talk of one in Chile and off of South Korea. And we may get to see more research in this.

[00:22:16] James Lawler: Interesting. So we’ve just covered ocean iron fertilization. And I’d love to move now to artificial upwelling and downwelling.

[00:22:25] Wil Burns: So the idea of artificial upwelling is to try to stimulate primary production in the marine environment by drawing nutrient rich waters from deeper in the ocean and introducing them into the surface areas.

And at that point it starts to look a lot like ocean iron fertilization. The idea is that those increased nutrients will stimulate phytoplankton production and the biological pump will be put on steroids. Right? So you’ll get a lot more ultimate sequestration of phytoplankton and there’s a range of technologies that people have proposed. There’s things called salt fountains that essentially use the buoyancy of the saltwater to utilize pipes that would send these nutrients up.

We’ve talked about using pumps and other kinds of approaches to do this.

[00:23:15] James Lawler: And downwelling is essentially just pulling those, just sort of accelerating that cycle of moving carbon rich content from higher ocean levels down into the lower, you know, below the solar layer.

[00:23:30] Wil Burns: Yeah. Yeah. So it’s enhancing the, what they call the solubility pump.

[00:23:36] James Lawler:  Right. So on that, so how advanced are we in our understanding of whether this would work or, you know, how feasible?

[00:23:42] Wil Burns: Yeah, not advanced at all. Very little research in either context. Lots of questions. Some people think especially upwelling could be a massive disappointment in terms of what we would ultimately get. Risks associated with both of these, again, changing biogeochemical cycles and things like that. That’s one thing I’d like to add about ocean iron fertilization is it has all kinds of risks associated with it also. It might result in massive proliferation of certain kind of phytoplankton, right? Cause it’s not like Macy’s, you don’t get to go in and choose what you want. You get what you get. And if there were proliferation of phytoplankton species that the zooplankton couldn’t eat in the area, you could have a trophic cascade where the zooplankton species start to decline the higher order organisms decline. One of the experiments showed massive production of one kind of phytoplankton that the zooplankton didn’t like, right. So if you did this at a basin-wide scale, it’s serious, it could also rob other areas of nutrients. And so you might have fisheries downstream that no longer have the nutrients that they need to thrive.

Same sort of thing obviously with ocean upwelling, anything associated with phytoplankton production potentially has those risks.

[00:24:54] James Lawler: Got it. So moving onto, we have ocean alkalization ocean, ocean liming. What is this?

[00:25:00] Wil Burns: Yeah. So the idea here is that you add either lime to the ocean in the form of either calcium oxide or calcium hydroxide or calcium carbonate. Or you add silicate materials, such as olivine to the oceans, that changes the pH of the oceans. It sends it higher toward the alkaline side of the scale. It strips hydrogen out of the oceans. It ultimately transforms CO2 into bicarbonates and carbonates that can ultimately end up in the bottom of the oceans.

So you’ve decreased the amount of CO2 in the oceans. And so again, that pressure system that you have it now means that the equilibrium has changed and more of the CO2 in the atmosphere can be introduced and sequestered into the oceans.

[00:25:49] James Lawler: And so this is one that presumably we can have some idea about total sequestration capacity, given that we know what that chemical equation is. How much tonnage of all of olivine would we need, or, some of these other minerals, would we actually need to make a serious dent from a gigaton you know, gigaton, CO2 sequestration perspective.

[00:26:13] Wil Burns: It is remotely feasible, but it has some challenges. First of all, I’ll tell you that the estimates of actual sequestration, despite the fact, as you said, there are formulas, are all over the map because they’re based on different assumptions of feedbacks in the system, sustainability limitations and so forth.

And so one study said that at the most, this could draw down atmosphere, concentrations of CO2 by about 30 parts per million. Other studies have gone up to as much as 430 parts per million, right. Anything that has that kind of error bar, or range, leads you to believe that there is a lot more research to be done.

So we don’t know. If you were going to produce, the amount of limestone or lime that you needed or olivine, it’s going to come with risks and costs. It’s going to have huge energy requirements, right? To grind up large amounts of olivine. Especially if you’re introducing it into the oceans, it has to be very fine, right. And so it requires a lot of grinding, a lot of energy, potentially has health risks associated with releasing fine particulates into the atmosphere. Same thing with lime and limestone. It’s, those energy costs will reduce its effectiveness. Some studies say by somewhere between 17 and 20% because of the CO2 releases associated with the production of the materials.

It also has huge costs. Some studies say maybe $2, $3 trillion a year, right, associated with producing the minerals, transporting them, dispersing them. Right. And so we have to decide from an opportunity cost perspective, if that’s our best use of our money.

[00:27:56] James Lawler: So that actually leads us to our last item here, which is blue carbon. So what is blue carbon?

[00:28:03] Wil Burns: So blue carbon are things such as sea grasses, mangroves and salt marshes, which take up carbon dioxide, right? And these ecosystems of course have lots of other co-benefits. They provide critical sustenance and protection for a lot of species. They provide flood breaks, right. And areas like Malaysia, the Philippines, Florida, New Orleans were much better off when they had more of these.

And so, the idea is first of all, to avoid further losses of these blue carbon resources, because that releases CO2, given the fact that they’re sequestering it, and to try to enhance growth of these, to both get the carbon sequestration benefits, as well as some of the other co-benefits.

And then some people also talk about macroalgae, things like kelp, for example, independent, and put it in a separate box, but it’s another ocean-based nature-based solution that could sequester substantial amounts of carbon dioxide. And we even have companies now that are seeking to develop business models to be able to sell carbon credits in that context.

The issue is that there are some real limitations in terms of how much it gets us, right. It’s about 200 million tons of CO2 that’s ultimately stored right now with blue carbon.

[00:29:25] James Lawler: Sorry, the 200 million tons, that’s an annual number?

[00:29:27] Wil Burns: That’s an annual number.

James Lawler: And that’s through natural, you know, just what’s happening naturally in the oceans through kelp and mangroves, like all these things?

[00:29:39] Wil Burns: Yeah, you know, some people say that realistically, if we were to intervene and try to escalate that maybe we get to half a gigaton.

Right. That ain’t nothing. Right. Because again, there’s lots of co-benefits. Right. And it can be done usually pretty inexpensively. So there’s every reason to encourage that to happen. But it in itself does not get us to where we need to be.

[00:30:01] James Lawler: You mentioned that in some of the more optimistic blue carbon scenarios – which is again, the ocean nature-based CDR techniques like kelp, algae, et cetera – We could sequester about half a gigatonne?

[00:30:13] Wil Burns: Well, let me clarify that. Usually when we talk about blue carbon, we’re talking about sea grasses, mangroves and salt marshes. Okay. Kelp, which fits in the category of macroalgae, and often doesn’t get put in the same bucket, may have more potential. Okay. But kelp’s interesting that way. As I said, there’s at least one company, more on the horizon, that are talking about developing huge amounts of kelp in the ocean, kelp farming, right? This company in Maine called Running Tide is proposing that they grow kelp on buoys, and then after about seven months, the weight of the kelp would sink the buoys and the buoys would be biodegradable. The kelp drops to the bottom of the ocean. It has sequestered substantial amounts of carbon. It ends up in sediments and the pressure in theory at least holds it there for thousands of years. Right. Which would buy us a lot of time. Running Tide argues that ultimately they may be able to put millions of buoys into the ocean that could sequester gigatons of carbon dioxide.

But there’s a couple of things to ask. The first is, is that true? We don’t know yet, right? Again, a lot of this is back of the envelope sort of estimates. Second of all, is what are the potential negative implications of putting millions of buoys and that much kelp in the ocean?

Cause one of the things that I don’t believe is that nature-based solutions are necessarily an unalloyed good. In the terrestrial context, if you plant huge amounts of trees and you crowd out savannah’s and prairie grasses and things like that, and you take huge amounts of water and fertilizer. It’s not necessarily an unalloyed good at some scale. Okay.

I think the same is true when it comes to kelp. One of the things that we worry about is if you were putting millions of buoys into the oceans and producing huge amounts of kelp, would that kelp ultimately attract certain sort of opportunistic predators that would thrive in that environment, that would ultimately alter, the structure of ecosystems in the oceans?

And the answer is we don’t know. Another thing is that these buoys, ultimately, before they sank, could take on a lot of invasive species that could float in coastal areas and introduce an array of species within exclusive economic zones that don’t exist.

If you put millions of buoys into the oceans with huge ropes on them, you may increase, marine-mammal entanglements, ship strikes, things of that nature. There’s a lot more research that needs to be done, in my opinion, before you go from the roughly 1500 buoys that they’re looking at in field research, to putting millions in the oceans, which is why you need international treaty regimes and national regulation, in all cases.

[00:33:08] James Lawler: You’ve said a number of times that this or that technology requires more testing, requires more research. But inherently some of the challenges that require research, such as in this kelp example, require deployment at large scales. It’s going to be very hard to assess the effect of having a lot of kelp in the ocean without having a lot of kelp. And at that point, have you not already done damage?

[00:33:32] Wil Burns: Yeah, well, it can be done incrementally and hopefully as we get to larger scales, we will learn things that will tell us whether we should proceed or not. But at the same time, I think in most of these cases, we’re going to have to acknowledge that there’s just no such thing as a free lunch, right? When we look at things like ocean iron fertilization, because of the kind of signal to noise ratio, the natural variability of the system, in order to really test it, to determine its effectiveness, you’d have to go virtually basin-wide, right? You might have some potentially irreversible impacts in those cases.

We have put ourselves, ‘we’ – my generation, my parents’ generation – have put ourselves in a position where we have to contemplate these risky technologies because of the dire implications of not considering them, but we have to acknowledge the fact that there are risks and that some of those risks carry huge uncertainties that we won’t know the answer to until we scale up. I don’t want the private companies alone involved in this. I want the international treaty regimes that have already to some degree, talked about this and talked about the need for risk assessment protocols and only doing it for scientific purposes initially. Not selling credits in open markets until we know more, to have a role to play in this, and not just allow private companies to be cowboys in the oceans.

[00:34:59] James Lawler: So given how long it takes to develop and test new technology, get it permitted and built up to sufficient scale, can ocean CDR come online to help our planet in a timely fashion? For example, wind and solar has taken more than six decades to get to its current stage.

[00:35:14] Wil Burns: I think the answer, and again, I may get some blow back from other people in the CDR community, is I think that’s exactly what is likely to happen.

I think that CDR will take a long time to deploy. CDR, once it’s deployed on a large scale, it takes a long time to have any impact. At a really large scale, it could draw down CO2 concentrations in the atmosphere probably by one to two parts per million per year, right? So it’s going to take a long time to have an impact.

I think that what its virtue may be is that in these overshoot scenarios, when we almost invariably go past two, probably three degrees Celsius toward the end of the century, if we’re deploying these in earnest, it may help us draw temperatures back down. Now that doesn’t guarantee you get the same world, right? You may have had non-linear changes when temperatures go to two or three degrees that are irreversible but it may help us to bring temperatures back down and ameliorate some of the impacts. I don’t think it’s helping us stay below these thresholds. I don’t see us doing that.

[00:36:18] James Lawler: I wonder if you could say one or two words on the legal frameworks for dealing with these, you know, marine geoengineering projects. Can anybody go out and plant a bunch of kelp in the ocean?

[00:36:32] Wil Burns: Well, at least in theory, they should not be able to. We have a treaty called the London Convention. It involves dumping of things into the oceans. When we engaged in ocean iron fertilization experiments, they passed a resolution that said, if you’re going to do that, you can only do it at a small scale for scientific purposes and subject to a risk assessment process that has to be approved by the government that you’re flying your flag or operating under.

That was just for ocean iron fertilization. But I think for anything that tries to put things in the oceans to sequester CO2, it’s likely that London would exert some sort of jurisdiction, and should quite frankly, because we don’t want, again, just the private sector to be making these decisions.

And so I think London could have a role to play in this. The Law of the Sea Convention says that you can engage in research, you can engage in deployment of things into the oceans, but you’re supposed to consult other governments and if it has negative impacts, there can be liability, right? And so it provides a framework for doing that.

The Convention on Biological Diversity also passed a resolution that says if you’re going to intervene in the oceans to alter the climate, climate geoengineering more broadly, again, small-scale no commercial enterprises at this point, and risk assessment.

So I think if people are engaged in this research, in the open oceans they should not be doing so before they’ve engaged in these processes. And I think in the longterm for investors, investors should demand that because otherwise it’s going to get a backlash that’s going to set this research back, and it’s also likely to result in far riskier enterprises than if there is a government private enterprise cooperative approach.

[00:38:21] James Lawler: Thank you so much Wil, it’s been a really fascinating conversation and such a pleasure to talk to you today.

[00:38:26] Wil Burns: Thank you very much, James.

[00:38:31] James Lawler: That was Dr. Wil Burns, Professor of Research and Founding Co-Director of the Institute for Carbon Removal Law & Policy at American University. If you’re interested in more information on ocean cdr, visit our website at www.climatenow.com where you will find the transcript to this podcast and links to additional resources. You can also find other podcast episodes, our video series, and sign up for our newsletter to receive updates on new releases and live podcast tapings. If you want to get in touch, email us at contact@climatenow.com or tweet us @weareclimatenow. We hope you’ll join us for our next conversation!

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