Latest / Stereo Chemistry / C&EN Uncovered: Can altering ocean chemistry fight climate change?

Transcript

C&EN Uncovered: Can altering ocean chemistry fight climate change? · Stereo Chemistry

0:00
Craig Bettenhausen: Craig, welcome to CNN uncovered. I'm
0:02
Craig Bettenhausen. CNN uncovered is a podcast series
0:05
from Stereo Chemistry. In each episode, we'll take another look
0:07
at a recent cover story in chemical and Engineering News,
0:10
and hear from CNN reporters about striking moments from
0:12
their reporting, their biggest takeaways, and what got left on
0:14
the cutting room floor. This episode, we're looking at a
0:16
recent cover story about a CO two abatement method called
0:19
Ocean alkalinity enhancement that aims to use the world's
0:22
oceans to remove more carbon from the atmosphere. Are Earth's
0:25
vast oceans our biggest allies in the fight against greenhouse
0:27
gasses. Can we augment the power of nature to keep our planet
0:30
alive longer? We'll put a link to the story in today's show
0:33
notes. I'm here with CNN assistant editor Fiona Samuels,
0:36
who wrote the article. Hi Fiona.
0:37
Fionna Samuels: Hi Craig. It's so nice to be here.
0:39
Craig Bettenhausen: Yeah, good to have you.
0:44
for
0:44
So for anyone that hasn't had a chance to read the story yet,
0:46
can you give a brief recap of what's in the article? Yeah, so
0:49
basically, I reported on a few different experiments, field
0:53
trials, specifically, that are happening around the world to
0:57
look at how we can add alkaline substances to ocean water in
1:02
order to help it draw down more carbon dioxide from the
1:05
atmosphere. And all of this is in an effort to sort of stymie
1:09
the worst effects of climate change. And how did you get
1:13
interested in this topic? It actually started out looking at
1:16
solar radiation modification, or solar geoengineering, which is
1:20
putting stuff into the atmosphere to reflect sunlight
1:22
back into space. But it turns out that there are almost no
1:27
field trials happening in that space right now because it's so
1:31
controversial, and the method is very questionable. But there is
1:35
quite a few different things happening in the marine carbon
1:39
dioxide removal space. So instead of reflecting sunlight
1:42
to cool the planet, removing carbon dioxide to help cool the
1:46
planet, interesting. So one of the things I had noticed in your
1:48
story is this experiment called Loch Ness. Tell me about Loch
1:51
Ness. The experiment not the Celtic sea monster or both. I'm
1:54
flexible.
1:56
Fionna Samuels: So unlike the monster, I guess this experiment
1:59
is real and it's officially happening. They just got the
2:03
permit, finally approved with the EPA. It's being led by a
2:07
researcher at Woods Hole Oceanographic Institute. His
2:10
name is Dr Adam Subhas, and what they're doing is they are
2:14
releasing a solution of sodium hydroxide into the water and
2:19
looking at where that alkaline water goes, and measuring a
2:23
whole bunch of different things to try to see if they can
2:26
quantify how much carbon dioxide is absorbed by the water because
2:31
of that increased alkalinity. Seems too simple to be
2:35
intuitive. Can you explain how would dumping a bunch of lye
2:38
into the water do anything about carbon dioxide in the
2:40
atmosphere. Well, so carbon dioxide dissolves in water
2:43
naturally. This is an ongoing geochemical process, and when
2:46
the gas dissolves into the water, it quickly reacts to form
2:50
carbonic acid, which then dissolves into different
2:53
carbonate ions. And because it's an acid protons, so that's why
2:57
we get ocean acidification. And it was really interesting
3:01
because many of the researchers that I spoke to for this story
3:04
started off as researchers of ocean acidification. So the pH
3:10
plays a big role in how much carbon dioxide can be absorbed
3:13
and then sequestered in ocean water. And by raising the pH or
3:18
making it more alkaline, not only are you sort of combating
3:22
that acidification that happens with carbon dioxide dissolution,
3:25
but you're also making it so more carbon dioxide can be
3:29
absorbed and then sequestered as carbonate ions and bicarbonate
3:33
ions. It's a little bit like magic, to be honest.
3:37
Craig Bettenhausen: And what kind of scales would this need
3:38
to operate on to make an impact?
3:41
Fionna Samuels: Well, that's a great question. So right now,
3:43
humanity is releasing carbon dioxide on gigaton orders of
3:47
magnitude. So that's 1 billion metric tons, and it's our annual
3:51
emissions are close to 40 billion metric tons. Obviously
3:56
we need to reduce emissions. That's number one. But there are
3:59
certain sectors that can't be easily decarbonized. So
4:03
aviation, agriculture, those cows are going to keep farting.
4:07
So we need to do more than just radically decrease emissions.
4:12
Scientists think we need to also start removing carbon dioxide
4:15
from the atmosphere, but if we're thinking on gigaton scale
4:19
of emissions, we want to probably remove gigatons of
4:24
carbon dioxide. That would be great. We can't do that right
4:26
now. We're not even to millions of metric tons. So one of the
4:31
researchers, David Ho, had a really good analogy. He thinks
4:35
of carbon removal like a time machine. So if you're thinking
4:38
we're emitting 40 billion metric tons of carbon dioxide annually
4:43
around the globe. And if we could remove 1 million metric
4:47
tons with these carbon dioxide removal techniques, you would
4:50
have had gone back 13 minutes in time. That's equivalent to 13
4:54
minutes of carbon emissions. So the scale is huge, and.
5:00
It's impossible to do it with carbon dioxide removal
5:03
techniques alone. Emission reduction is absolutely vital.
5:06
Craig Bettenhausen: So I can imagine getting sodium hydroxide
5:09
on a laboratory scale. You can get it at the hardware store,
5:12
but on that kind of scale, we're not just talking about that kind
5:15
of material. Where are we going to get that much base
5:18
equivalence, that much alkalinity? Yeah,
5:20
Fionna Samuels: so now you're talking about sort of the life
5:22
cycle of these sort of techniques. And there's actually
5:24
a few different techniques. It's not just putting sodium
5:27
hydroxide in the water. So with sodium hydroxide, the Loch Ness
5:30
team is truly only interested in figuring out if ocean alkalinity
5:36
enhancement is a viable solution, and so they're
5:39
basically using the cleanest form of alkalinity in the sense
5:44
that sodium hydroxide, they can be incredibly confident of what
5:47
they're putting in the water. They can be very confident about
5:49
the kinds of reactions that are happening. Sodium ions already
5:53
exist in seawater. Hydroxide ions also exist in seawater, but
5:56
obviously at a far lower abundance and the pH, they very
6:02
well constrained how the pH will fluctuate after their release
6:06
and at different timescales after the release. That's why
6:08
they're using sodium hydroxide in the real world. You're right.
6:12
Sodium hydroxide is not necessarily a viable way to
6:16
increase the alkalinity of these bodies of water, because you
6:19
would need vast amounts of it. And right now, a lot of sodium
6:22
hydroxide is actually produced in chlorine chemical reactions,
6:26
but we produce chlorine for other chemistry is happening
6:29
anyway. Other researchers are looking at alkaline minerals. So
6:33
like olivine is a big one, and that would come from mining
6:38
minerals around the world. We humanity, different people are
6:41
already sort of spreading these mined minerals on agricultural
6:46
fields and elsewhere. So those sources of mineral alkalinity
6:51
exist already, which is why these folks who are using
6:55
minerals argue that that might be a better option. A third
6:58
technique actually uses electrolysis to separate
7:02
alkaline seawater from acidic seawater. But the problem with
7:04
that is then you have a bunch of acid, and there's not a huge
7:07
market for acid to change the pH of things. So you're right when
7:12
it comes to scalability, the life cycle of these chemicals is
7:16
very important to consider, where they're coming from, where
7:19
the byproducts are going. If we're thinking about mining
7:22
alkaline minerals, you need to think about if those mines are
7:26
emitting more carbon than can be taken up by the ocean or other
7:30
carbon dioxide removal techniques where the energy is
7:33
coming from. All of this stuff is a big question mark. The
7:36
field trials right now are really focused on whether or not
7:40
the chemistry is workable from a standpoint of like we
7:44
theoretically know that this should work, but does it in the
7:47
real world.
7:49
Craig Bettenhausen: So that suggests the question, how are
7:51
they going to tell what are they measuring to see if this
7:54
Fionna Samuels: works? They're measuring a bunch of different
7:56
things. So the Woods Hole folks are. They're throwing the whole
7:59
instrument laboratory at the problem. They're going to be
8:03
taking water in through the ship that they're driving and
8:06
releasing the alkaline solution behind to sample for the
8:10
pressures of oxygen and carbon dioxide dissolved in the water.
8:14
They're also going to be looking at how the pH changes. They're
8:17
going to be looking at total dissolved inorganic carbon,
8:21
which is all those carbonate ions. They're going to be
8:23
looking at changes in the marine life in the area. Of course,
8:29
they're going to make sure that they're not, or they plan to
8:31
make sure that they're not going to be dumping anything on a
8:35
whale's head, right? But as long as there's not any big animals
8:40
around the they're gonna dump this solution, and then they
8:44
will be taking a plankton net and dragging the plankton net
8:48
behind the boat to look at how these little, tiny marine plant,
8:53
like creatures, plankton, is hard to find. Sorry,
8:56
Craig Bettenhausen: yeah, things at the bottom of the food web,
8:59
how the bottom of the food web? Yes, yes, they're
9:01
Fionna Samuels: looking at how plankton, which is the bottom of
9:03
the food web, will be affected by this experiment in the real
9:07
world, because other researchers have already looked at how
9:09
plankton are affected in microcosms and mesocosms, which
9:13
are basically containers filled with seawater.
9:15
Craig Bettenhausen: Yes, I liked in your story, you had this
9:17
vocabulary where the mesocosms, and started right off with that,
9:20
I immediately, I was like, I need to I'm in just so I can
9:22
find out what that word means.
9:24
Fionna Samuels: Yeah. So mesocosm is basically like a
9:26
giant test tube, like 1000s of liters of water in a test in an
9:30
enclosed container. And then the microcosms are smaller volumes
9:33
of water, so more on the liter scale. And the nice thing about
9:36
microcosms is that, because they're so small, you can
9:39
standardize a bunch of experiments across the world,
9:42
you can have a bunch of different labs doing a very
9:44
similar experiment with different samples of water. So
9:48
like you can go out and scoop ocean water off the coast of
9:51
Maine or off the coast of Australia or off the coast of
9:55
England, right? Like any of these places
9:57
Craig Bettenhausen: and the mesocosms, these are in the
9:59
water. But not the water can't pass from one side of this
10:02
mesocosm out into the general correct
10:04
Fionna Samuels: so the 1000 liter containers, the mesocosms,
10:07
they are just containers in the ocean. The researchers flood the
10:11
container, collect all this water and then make sure that if
10:14
there are any fish or anything else accidentally get caught up,
10:17
to remove the fish. Because that's too complex, they're
10:20
really only interested in the plankton, the bottom of the food
10:23
web at this point. Historically, the research so far has really
10:26
only been interested at that level. Future research, though,
10:29
might look at some fish larva, but yeah, and then that water is
10:32
totally isolated from the surrounding water, so anything
10:35
that's added to the mesocosm is contained within the mesocosm,
10:39
and you don't worry about putting anything into the
10:43
surrounding open water system.
10:44
Craig Bettenhausen: Yeah. I wanted to ask about that because
10:46
you encountered some critics, some people that aren't happy
10:49
about this. Were they worried about the Loch Ness project
10:51
specifically? Were they skeptical about ocean alkalinity
10:54
enhancement, or were they against climate change
10:56
mitigation as a whole effort?
10:58
Fionna Samuels: Yeah, so I think, I think you're talking
11:00
about James Carey, one of the sources in my story, yes, he was
11:04
skeptical about Loch Ness specifically, but also about
11:07
ocean alkalinity enhancement, more generally, Loch Ness, he's
11:10
not totally convinced that they will be able to measure all the
11:13
things that they want to measure, because it's just open
11:15
water systems are incredibly complex, and so measuring
11:19
anything in the open ocean is going to be very difficult. The
11:23
Signal to Noise is very hard to tease out. So he was skeptical
11:28
about that. But more broadly, I think he has concerns about
11:31
scalability. And scalability is a big question in all of these
11:35
things, because we are emitting so much carbon dioxide that it
11:40
almost doesn't pay to do any of this before seriously figuring
11:45
out ways to cut emissions. The scientists, of course, argue
11:49
that we need to have a solid research based foundation to
11:53
even have discussions about carbon dioxide removal on a
11:57
grand scale. But others, of course, worry that focusing on
12:00
research for future applications, sort of moves the
12:04
goal post for the current needs of just emission reductions.
12:08
Yeah, I run
12:09
Craig Bettenhausen: into that debate a lot like I should be
12:10
redoing this at all, and it's a lot of the same dynamics of a
12:13
lot of people think we will need these carbon removal
12:15
technologies a little bit down the line. But yeah, there's
12:19
lower hanging fruit that we should be picking but it won't
12:21
be ready then, if we don't start working on it. Now, it's a
12:24
difficult balance.
12:25
Fionna Samuels: Yeah, definitely. And again, all the
12:26
researchers that I talked to were not interested in selling
12:30
carbon credits and they weren't interested in trying to make
12:34
this a commercial sort of opportunity. They're really just
12:38
wondering, Will this work, and the models that climate
12:43
scientists have run suggest that ocean alkalinity enhancement and
12:46
other carbon dioxide removal techniques could be incredibly
12:50
valuable, worthwhile pursuits in the fight against climate
12:53
change. But without doing these experiments in the real world,
12:58
in field trials, there's just a big question mark about whether
13:01
the real world is too complicated for this to work.
13:05
Craig Bettenhausen: I'm gonna reveal my chemist background and
13:06
say I'm curious about at the lab scale, though. I mean, is there
13:09
solid proof at the liter scale that making the solution more
13:12
basic will cause carbon dioxide to dissolve into it? Do we have
13:15
that basis? Really solid?
13:17
Fionna Samuels: Yeah, they figured that out. They are
13:20
confident that carbon dioxide will dissolve into water more
13:23
readily if the water is more basic, which is actually part of
13:27
the reason why the oceans are so powerful already. So the oceans
13:31
are absorbing vast amounts of carbon dioxide every year, and
13:34
that's because their sort of inherent pH is around 8.3 which
13:40
is quite basic compared to other bodies of water. In fact, tap
13:44
water is often more acidic than that, and sodium hydroxide is
13:48
often used in municipal water treatment plants in order to
13:52
change the pH which helps prevent corrosion from pipes. So
13:57
you know, humans are already doing pH modification on our
14:00
drinking water and the ocean is already super basic. It's just a
14:05
question of whether or not we can see these effects in the
14:08
real world, because the ocean is so huge.
14:11
Craig Bettenhausen: Yeah. Are there any other characters from
14:13
your interviews that you wanted to bring in but didn't quite
14:15
Fionna Samuels: fit? That's a good question. Yeah, the section
14:17
that ended up not going into the piece was really about how the
14:21
researchers are communicating with the public about their
14:23
work, which was more of like a social sciences kind of
14:27
discussion. And those folks were all great, and there are some
14:30
really fabulous social science research happening in this
14:33
space, and really important takeaways, like you need to talk
14:37
to stakeholders before starting your experiment, which seems
14:41
really obvious, but sometimes scientists are so excited to,
14:46
you know, go out and start collecting data that it might
14:48
not occur to them that the people living in these areas
14:52
will feel very betrayed, almost, if this kind of science happens
14:57
without any of their input. And so it's incredible. Incredibly
15:00
important to have the local communities involved in the
15:04
whole scientific process from even before applications for
15:08
permits are submitted. And
15:09
Craig Bettenhausen: so, I mean, how was the community responding
15:11
to the Loch Ness experiment? I mean, they had your person that
15:14
was opposed to it because they didn't think it was going
15:16
Fionna Samuels: to work, yeah. So there have been some vocal
15:18
opponents in the local community, but it also seems
15:21
like there was potentially less I mean, there was some reporting
15:25
that there are local community members who are still not
15:28
convinced that it's a good idea to put stuff into the water. But
15:32
there were also the Loch Ness researchers did take lots of
15:37
conversations into account and change some of their
15:41
experimental design based on what the local fishing community
15:45
said and other stakeholders wanted from the experiment.
15:49
Craig Bettenhausen: Yes, I guess this is happening out of Cape
15:50
Cod, and that is not an area known for a lot of community
15:53
activism. It's not a quiet sit back and let everything happen
15:56
to them, kind of a place, yeah,
15:57
Fionna Samuels: the most important thing with all of
15:59
these environmental field trials is to engage community members
16:03
early and for the entire time that you're doing the
16:08
experiment, and do more than it goes beyond just educating
16:11
people. It actually requires that they are involved in the
16:15
decision making process. So Cape Cod is not the
16:17
Craig Bettenhausen: only place that they're looking at this
16:19
kind of thing. There are some other experiments probing this
16:22
idea of ocean alkalinity enhancement.
16:24
Fionna Samuels: Yeah. So the other experiment that I talked
16:26
about in the piece was really, really small scale, tiny scale
16:29
off the coast of Australia. They're putting minerals down in
16:32
the sediment in the water to just see how worms and other
16:36
creatures that live down there will respond their results this
16:40
really recent. It was our winter, their summer, but they
16:43
just recently finished that project, and they told me that
16:47
their results are promising. The worms don't seem to care. But
16:50
the scale at which they were doing it is so small compared to
16:54
what will need to happen. There
16:56
Craig Bettenhausen: are scale where they're like swimming down
16:58
there with a single vial. They're
16:59
Fionna Samuels: swimming down with a single vial, opening it
17:02
up, pouring it and then watching for a few weeks, taking samples
17:07
every few weeks, and then taking up sediment samples. Obviously,
17:10
that's such a small scale that that's not what any sort of real
17:14
world application will look like. We do actually have
17:18
examples of real world mineral applications. So there's a
17:21
company called Vesta that has done some olivine trials where
17:25
they've put huge amounts of crushed olivine sand along, I
17:29
think it was the coast of New Jersey, and off the coast as
17:32
well, obviously, tons and tons of crushed rock is a lot
17:37
different than a tiny little bio of crushed rock. And they're
17:40
interested in figuring out some kind of carbon credit, some way
17:44
of making this technique profitable. If there's any
17:48
future in these sorts of techniques, there should be
17:51
small scale, very safe field trials before actually
17:56
approaching anything that looks like what we would need to
17:59
combat climate change in a real way, which is unfortunate. It's
18:02
like such a bummer, right? Like, the best solution is for
18:06
everyone to bike to work and go from there,
18:10
Craig Bettenhausen: stop eating so much meat. Compost. Yeah, oh
18:12
God.
18:13
Fionna Samuels: There's this carbon dioxide removal technique
18:16
where you use electricity to take carbon dioxide out of
18:21
seawater and pretty much, and then you put that carbon dioxide
18:24
into the ground, you inject it into some sort of geologic
18:28
formation, pretty much everyone thought that that was a very
18:31
silly approach, because the ocean is one of the most stable
18:36
places for carbon dioxide to Live. Carbon dioxide is
18:40
sequestered into carbonate, which is all of those sorts of
18:44
ions that are in the ocean will stay in the ocean as carbonate
18:47
for 10,000 years. So it's silly to take stable carbon dioxide
18:53
out of the ocean to put somewhere else, because the
18:56
ocean is a really good home for it. So
19:00
Craig Bettenhausen: in June, actually, I'm going to visit a
19:02
pilot rig in New York City, where a startup is testing a
19:04
system like the enhanced ocean alkalinity that you're
19:07
describing. They're going to add reactive alkaline minerals to
19:09
remove CO two this time from the East River in New York, instead
19:12
of the ocean. What should I ask them? What should I be looking
19:14
for? What
19:16
Fionna Samuels: you should ask them, how they're measuring how
19:18
much carbon dioxide is being removed from the air, how
19:21
they're measuring carbon dioxide uptake. All
19:23
Craig Bettenhausen: right, so is there anything else to me
19:25
reporting that you wish you could have fit in somehow?
19:27
Fionna Samuels: The one thing that I didn't emphasize, and I
19:30
would like to have emphasized, is that a big piece of all this
19:33
research is what the researchers called monitoring, reporting and
19:37
verification, and that goes into sort of figuring out if this is
19:41
a usable technology for something like carbon credits.
19:44
And what that means is that you need to be able to monitor how
19:48
much carbon dioxide is removed. You need to be able to report
19:51
it, which is a whole different sort of infrastructure that's
19:54
separate from the science. And then you need to verify it so
19:58
other people need to be able to come in. And measure the same
20:01
thing that you measured. And a lot of this research right now
20:05
depends on modeling. There are very few field trials, although
20:08
it's a growing field so there will likely be more field trials
20:12
in the near future, but monitoring carbon dioxide
20:16
removal on a global scale is going to be incredibly
20:18
challenging, which is why these sort of open field trials are so
20:21
important, because if you can monitor it on the small scale,
20:25
and you can prove that you are able to monitor how much carbon
20:28
dioxide is removed on the small scale, and then other people are
20:32
able to verify that you are measuring what you think you're
20:35
measuring, then that basically opens the door to realistic
20:40
sorts of deployments in the future.
20:42
Craig Bettenhausen: Okay, well, Fiona, thanks for diving deep on
20:44
this with us.
20:44
Fionna Samuels: Thanks for having me. Thank you so much.
20:46
Craig Bettenhausen: And I usually use that line. It's not
20:47
always literal, but this time it was,
20:49
Fionna Samuels: I was gonna say, that's a great pun you caught me
20:52
off guard with that one.
20:55
Craig Bettenhausen: You can find Fionna Samuels story about
20:57
oceans as climate change allies on CNN website, or in the April
21:00
14, 2025, print issue of CNN, we put a link in the show notes
21:04
along with the episode credits. We'd love to know what you think
21:06
of CNN uncovered. You can share your feedback with us by
21:08
emailing C E N feedback at ACS, dot, O, R, G, you can find me on
21:13
social media as at Craig of waffles, Fiona. How can
21:15
listeners get in touch with you?
21:16
Fionna Samuels: I'm at F Morningstar on blue sky.
21:19
Craig Bettenhausen: All right, this has been C&EN uncovered a
21:21
series from C&EN Stereo Chemistry. Stereo Chemistry is
21:23
the official podcast of chemical and Engineering News. Chemical
21:26
and Engineering News is an independent news outlet
21:28
published by the American Chemical Society. Thanks for
21:30
listening.