Could the ocean be our solution to climate change?

USA Today

08-03-2025

Could the ocean be our solution to climate change? | The Excerpt
On a special episode (first released on March 6, 2025) of The Excerpt podcast:What if we can slow climate change by giving the ocean an antacid? It's called ocean alkalinity enhancement and it's exactly what researchers have been exploring for the last five years. But it's only recently that the idea has become a reality. Supporters of the technology say it's one of the most promising forms of carbon removal to date, a necessary step to meet climate goals even as the world cuts emissions. But in order to truly make a dent in the accumulated carbon in our atmosphere, it will need to be scaled up to massive levels – the question is, can it be done? And can it be done affordably? Jaime Palter, an associate professor of oceanography at the University of Rhode Island, joins The Excerpt to discuss the science and potential of this exciting new weapon in the fight against climate change.
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Dana Taylor:
Hello and welcome to The Excerpt. I'm Dana Taylor. Today is Thursday, March 6th, 2025, and this is a special episode of The Excerpt. What if we can slow climate change by giving the ocean an antacid? It's called ocean alkalinity enhancement, and it's exactly what researchers have been exploring for the last five years. But it's only recently that the idea has become a reality. Supporters of the technology say it's one of the most promising forms of carbon removal to date, a necessary step to meet climate goals even as the world cuts emissions. But in order to truly make a dent in the accumulated carbon in our atmosphere, it will need to be scaled up to massive levels. The question is, can it be done and can it be done affordably? Here to explore the tech and the possibilities is Jaime Palter an Associate Professor of Oceanography at the University of Rhode Island. Thanks for joining me, Jaime.
Jaime Palter:
Thanks for having me.
Dana Taylor:
Let's start with the basics. First, how does the ocean naturally absorb carbon? And then how does ocean alkalinity enhancement actually work?
Jaime Palter:
The ocean is a great ally in slowing the pace of climate change without any human intervention. As humans have put carbon dioxide into the atmosphere, the atmospheric concentration or what we call partial pressure of carbon dioxide increases and the ocean just tries to keep up and stay in equilibrium with the atmosphere. And in doing this natural chemical reaction, the ocean has absorbed about 25% of man-made emissions. When we talk about ocean alkalinity enhancement, we're talking about increasing that rate of ocean uptake by shifting the chemistry of the surface ocean to a state where the ocean can continue to take up even more CO2 than it would without the intervention.
Could the ocean be our solution to climate change?
Ocean alkalinity enhancement, if scaled up, could make a meaningful difference in fighting global warming.
Dana Taylor:
And then in what ways does this process of carbon removal differ from something like carbon capture and storage?
Jaime Palter:
So carbon capture and storage on land depends on these giant machines that pull carbon dioxide of the atmosphere and then have a highly concentrated CO2 source that needs to be stored in a safe reservoir. What we're talking about with ocean alkalinity enhancement is that the ocean itself would store the excess carbon dioxide as essentially a type of salt called bicarbonate or carbonate, which is already abundantly existing in the ocean as it is. In fact, the ocean has 50 times more carbon in it than the atmosphere in its natural background state. That carbon is mostly stored as bicarbonate and carbonate. So by increasing that storage, just a small percentage in the ocean can reduce the carbon dioxide in the atmosphere by a larger percent.
Dana Taylor:
Which is more effective and has the least negative impact?
Jaime Palter:
They're really different, and I would say the nomenclature has some subtleties. So carbon capture and storage typically is done at, let's say the scale of a power plant or somewhere that's making cement so that CO2 is kept out of the atmosphere at the point of creation, and it actually doesn't remove CO2 from the atmosphere. It just keeps it from getting in there in the first place. Whereas ocean alkalinity enhancement is meant to increase the ocean's ability to capture carbon after it's been emitted to the atmosphere. So actually dialing back the carbon dioxide that's already there, pulling it out of the atmosphere, and therefore reducing the rate or total global warming that we'll see.
Dana Taylor:
How does the process of alkalinity enhancement impact marine ecosystems, particularly sensitive environments like coral reefs?
Jaime Palter:
So this is an ongoing area of investigation and the oceanographic community is, we care deeply about the ocean. And so people want to know if this is safer than keeping the carbon dioxide in the atmosphere itself. And in fact, there's a fear that the ocean is becoming too acidic, that it's acidifying in response to the carbon dioxide that's being taken up as it is, but putting in substances that increase the alkalinity of the ocean is the reverse of ocean acidification. So whereas an acidified ocean can be corrosive to coral reefs and shellfish and the like, increasing the alkalinity should have the reverse effect in net if we put alkalinity into the ocean, but it allows it to take up more CO2, we should return to an equilibrium state that's not so chemically different from where we started. But it's true, we really need to assess this at every scale that it's proposed.
And so every project that is like trying for a field trial has a fleet of biologists that are measuring everything they can to check and double check that this isn't a problem, or if it is, to be transparent and open about that and assess what happened. So one way oceanographers and biologists have been assessing the safety is in experiments that we call mesocosm experiments. They're kind of mid-scale tanks that are filled with natural seawater, including all of its life. And in those tanks we can add various doses of the alkaline substance and see if it has any effect. And there's a high level of commitment among the scientists to publish those results and be fully transparent about that. And they're coming out as soon as people can get the work done very carefully. And so far, there are some types of alkaline sources that don't work as well as others, but by and large, pure alkalinity has been linked to very few biological harms.
Dana Taylor:
Jaime, what are the main challenges or risks associated with implementing ocean alkalinity enhancement on a large scale?
Jaime Palter:
Well, I'd first like to talk about the risk of giving people a false sense of security. The only way that any marine carbon dioxide removal or carbon dioxide removal approach makes a dent in the climate problem is if we pull emissions back to very close to zero. Right now, humankind emits about 40 billion tons of CO2 to the atmosphere, and there's no removal process that will touch that number. But if we pull that number down by 50, 60, 75, 80%, we start to have processes that can keep up. And so that's the first hazard, is giving people a false sense of security and putting the brakes on emissions reduction. We need to reduce emissions as quickly as possible. But I think your question is more about if at scale would this harm the ocean? And again, that is a huge research effort to figure out if that's the case with full transparency so that people can see the answer. And so far we have little indication that this would be harmful even at scale if we can find the right alkalinity sources that do no harm to biological systems.
Dana Taylor:
What are the logistical challenges involved in distributing alkaline substances in the ocean and how are they being addressed?
Jaime Palter:
It's a huge logistical challenge. Right now, we're not really at a deployment scale that has climate impact. We're at research scale, I would say, and small scale field trials. And some of these field trials are using existing infrastructure in places that have high social acceptance. So there's a great group in Canada called Planetary. They are using very pure magnesium hydroxide and putting that in the cooling waters of a power plant, already waters that were being manipulated by humans for a purpose of cooling a power plant. As long as they stay within safe environmental limits of pH, the acidity and particle or turbidity, how turbid the water is or filled with particles, then they pass their environmental requirements in Canada.
So that's a great way to try this out in a small scale. If we're going to scale that up, we could do that in lots of cooling power plants, like the cooling waters of many power plants, the wastewater in sewage treatment plants, things that are already not pristine and try to improve the water quality or at least do no harm. And then from there, with all the lessons we learned from that, there could be more scaling from that point. Challenges include sourcing pure sources of alkalinity that won't contaminate the water and then getting it into the water at scale because all of those point sources, what we call point sources, power plants, wastewater treatment plants, won't scale to a climate relevant number.
Dana Taylor:
What about the cost associated pulling off something as large as ocean alkalinity enhancement? Is the technology even affordable at this point?
Jaime Palter:
Yeah. I always preface this by saying I'm an oceanographer, not an economist or a business person, but my understanding is that in terms of cost, the assessments I've seen puts it as competitive or below some of the solutions that are getting more attention, like direct air capture, because direct air capture is incredibly energy intensive, so you have to pay for that energy to run the machines that pull carbon dioxide out of the atmosphere. Whereas the costs here are really in sourcing the alkaline materials and making sure it gets into the ocean in a dissolved form, and those costs are much lower.
Dana Taylor:
What concerns have environmental groups and other communities expressed about the technology and how are scientists addressing them beyond transparency?
Jaime Palter:
People really see the ocean as a beloved and pristine space and want to keep it that way, and I totally respect that and respect everyone raising their voice to try to figure out if this is even something we want to try as a society. So people have been coming to public fora and speaking out when they feel that this is proceeding faster than their comfort level. In the meantime, scientists are starting what I would say very slowly and with these controlled experiments, things in laboratories and flasks, and then in mesocosms, these whole water experiments with all the life within them. And then scaling from there to small embayments at point sources like the cooling waters of power plants and trying to publish and make fully available, all of the results from that. I think that's our only path forward, and we'll see if that is acceptable to enough people to move forward. I agree that the oceans are invaluable commons that we all share and share with non-human life as well. And so we have to be respectful and take things slowly.
Dana Taylor:
What's next for research and development in the field of ocean carbon removal and alkalinity enhancement? Can you share a timeline for when the application of this kind of tech might be widespread?
Jaime Palter:
That's a tough question. So in terms of where we are now is we're running on many tracks in parallel. So a lot of biologists are still doing these kind of mesocosm tests to check for biological safety. In the meantime, there are a handful, maybe 10, field trials. These are really small field trials where they're deploying very moderate amounts of an alkalinity source like in Canada and tracking every measurable chemical and biological quantity in the affected area. And so these projects are just hitting the field this summer. It's an incredible effort to measure everything that's measurable, and a lot of times, even when we're just trying this for the first time, our best measurements can only see the perturbation, can only see the intervention right at the source where it's happening. The ocean has a lot of background variability in the carbon system, and so these perturbations are very small relative to the ocean's natural variability.
Dana Taylor:
Finally, I'm not a scientist, but ocean alkalinity enhancement does sound promising. Are there other technologies that you're interested in or hopeful about?
Jaime Palter:
Once we're talking about carbon dioxide removal? I would say the pathways are really limited. The one that I think are viable, scalable are not very expensive and energy intensive, and I think the two that I've seen that to me see most scalable are the ocean alkalinity enhancement and safest, and its kind of sister on land, which is called enhanced rock weathering. Both of these approaches are trying to remove carbon dioxide from the atmosphere through a chemical reaction with an alkaline substance and create bicarbonate and carbonate, which then is stable for thousands of years. There are lots of other ideas out there. My personal take is that they have a lot, all of them have many challenges. These two alkalinity enhancement in the ocean and alkalinity enhancement on land are the two that I find most promising personally.
Dana Taylor:
Jaime, thank you so much for joining me on The Excerpt.
Jaime Palter:
Thanks for having me.
Dana Taylor:
Thanks to our senior producers, Shannon Rae Green and Kaely Monahan for their production assistance, our executive producers Laura Beatty. Let us know what you think of this episode by sending a note to [e-mail]. Thanks for listening. I'm Dana Taylor. Taylor Wilson will be back tomorrow morning with another episode of The Excerpt.