 Welcome to Leckable Science here on Think Tech Hawaii. I'm your host Ethan Allen, and glad you could join us today. With me today in the Think Tech studios is Dr. Christopher Sabine. I've had him on before. He talked about plastics before, and now he's talking about his real research focus, which is carbon in the ocean. Welcome, Chris. Thank you. Pleasure to be here. Great to have you here, and this is a subject that's clearly of real importance to basically everyone on the planet. What can I say? And we all should know more about it. So I think people don't really understand the underlying importance of what's happening, why carbon in the ocean is so critical. Maybe you could start by explaining a little bit of that. Sure. So of course, most people have heard of climate change, global warming, which is resulting from the burning of fossil fuels and the accumulation of carbon dioxide in the atmosphere. Well, we can count up how much CO2 we should be producing from burning oil and coal. We know the efficiency of all those, and we know how much we're burning globally. And if we do that, we're also measuring CO2 in the atmosphere, like at the Montelua site, the famous healing curve. But if we look at how much is accumulating in the atmosphere, it's only about half of what we think is being produced from the burning of fossil fuels. So the big question was, where is it going? And we think that the oceans are one of the places where it's going. Sure, that makes sense, right? It's going to just dissolve into the water there, basically. That's right. And given the oceans cover 70% of the surface, that's not an unreasonable guess. The whole bunch that must be going there. Right. The problem is the oceans were so large, and we had so few measurements that it was difficult to actually quantify how much that the oceans were taking up. So at the time that I got my PhD 25 years ago, we really didn't have a good estimate of how much man-made CO2 was accumulating in the oceans. Right. But then, about a decade or so ago, I guess in the mid-90s, a little longer than a decade, you figured out some way to directly measure the carbon in the ocean, right? Until then, nobody had really done this, right? Correct. So after I got my PhD here in Hawaii, I moved to Princeton University and got involved in a global program where we started serving the oceans. And so I would get on a ship and collect data. And it was after serving the entire world, which took about a decade to do, that I pulled all that together and generated the first data-based, measurement-based assessment of man-made CO2 in the oceans. Oh, because before that, nobody had really measured that. They had maybe guessed at it from... Models. Yeah, models and back-to-end-look calculations and all. Exactly. Yeah, that's great. And then recently, you just a little bit ago published a paper in the Journal of Science, right, where you sort of took, I guess, that same data and now updated it with recent changes, right? Correct. So it's actually new data that we've collected. So we did this whole survey in the 1990s to get the first estimate of how much CO2 was in the ocean. But we recognized that over time, the rate at which the oceans are absorbing CO2 would change, that we decided that we needed to continue doing these surveys. And they take about a decade to complete. So this paper that we just published is the second global survey of carbon dioxide in the oceans and our assessment of how much man-made CO2 is there. Maybe this would be a good time to go to that first figure, because that's really what we're talking about, right? Sure. Yes. So walk us through this piece by piece, if you will, please. Okay. So the first figure is a – so this is what we call a column inventory map. So if you look at each square meter of the ocean, if you're looking down on the ocean, if you were to add up all of the man-made CO2 that's in that ocean, in that square meter, that's what this is a measure of. And so one plot is from the survey that we did in the 1990s. That's the middle plot, the B, right? Right. That's the one that says woes. Okay. And so that's the distribution that we saw back in the 1990s. The yellow being high, red being moderate, and blue being low, right? Exactly. Okay. The high values in the North Atlantic, for example, we see high values in the mid-latitude, southern ocean, low values in the Pacific. Right. Right. And so then we went back and redid that survey. The top plot then is a figure that shows how the carbon has changed since the 1990s to this mean year, 2007. Right. It shows a little bit lower, actually, in the North Atlantic, but in general higher, almost everywhere else. Much bigger lands across the Pacific, covering much more. And that's the key thing is we saw kind of two main results from that. One was the fact that the rate at which the oceans are absorbing carbon is increasing with time. And the other is that the places, the locations where it's being taken up is different. Right. And that's what we see in that figure, the bottom one. The difference between the two. Yeah. Okay. And so the blue areas are areas where there's less uptake. And the red areas are where there's more uptake. Right. We see, like you mentioned, for example, in the high-latitude North Atlantic, there's actually less carbon going in there than we would expect. Right. But so much more of the ocean now has much more carbon going in them than we would expect, yeah. Right. So the oceans are taking up CO2 at a much faster rate. In the 1990s, when we did the survey, it was taking up CO2 at a rate of about two pedigrams of carbon per year. Pedigrams being... A pedigram, so PETA is a one with 15 zeros after it. Okay. A pedigram is also a billion metric tons. Okay. And when you're talking about carbon, an analogy that I like to use, which doesn't work so well in Hawaii, but if you think of converting that carbon to coal, coal is almost pure carbon. It's actually about 80% carbon. But if you were to convert all that carbon to coal and put it in a coal train, you know, just a railroad train, a railroad train that would hold one pedigram of carbon would be 156,500 miles long. Wow. Yeah. So that's a lot of coal. A lot of carbon. So the oceans were taking up about two pedigrams of carbon in the 1990s, so twice that long. 300,000 miles, a train of 300,000 miles of carbon basically. Exactly. Wow. Today, or at the time of this latest survey, which is 2007, it's taking up at about 2.6 pedigrams of carbon, which is the equivalent of about 7 million metric tons of carbon per day. That's awesome. I mean, people do not realize when we're burning fires, running furnaces, driving our cars, anything like that is dumping carbon in the atmosphere, and you don't think of it as having much mass. Exactly. It's a clear gas, and that's just the carbon. Right. If you think of it as carbon dioxide, it's actually significantly more. Right. Right. That's a much heavier gas. Yeah. Wow. That's a whole lot. Let me shift from one and go back to that figure that we talked initially. Why are the areas of the ocean so different? Why are some areas taking up more and some areas taking up less, and why is this changing? Right. What we find is that the ocean is kind of a layered system, and in most places around the surface, all the carbon is entering from the atmosphere, right? So it's entering through the surface of the ocean. Right. And so the surface ocean is increasing at about the same rate as the atmosphere, right? So as the atmosphere goes up, some of that goes into the ocean and the CO2 increases. But because the ocean is layered, it takes a long time for the ocean to move that carbon dioxide down into the ocean interior, and that is kind of the rate limiting step that controls how quickly the oceans can absorb carbon dioxide. So different parts of the ocean that have different upwellings or downwellings are going to show different patterns. Exactly. So in the Equatorial Pacific, for example, is an upwelling zone. That's area where old water is coming up to the surface. So we don't see a lot of anthropogenic carbon there, which is the man-made carbon. In the North Atlantic, where you see that bright spot with a lot of carbon, that's an area where the water, I think of the waters that move north through the Gulf stream, they cool down as they move north. And then when they get off of Greenland and Iceland, they become more dense. They sink down into the ocean interior. With a bunch of carbonized water. Right. And so that carbon that they've absorbed from the atmosphere is now pushed down. That's the one spot where we actually see man-made CO2 all the way down into the bottom of the ocean at 4,000 meters. Yeah. Okay. Wow. That's fairly impressive. Yeah. So then when you go out to do this, maybe you can walk us through a little bit of what a trip like this is really involved in actually doing the science here. Right. So there's a couple of issues involved in it. One thing, when you're measuring carbon dioxide in the atmosphere, the atmospheric reservoir of carbon, the amount of carbon that's stored in the atmosphere is relatively small. So the amount that we're contributing from burning fossil fuels and other things is actually making a significant difference. We've gone from 280 parts per million in the pre-industrial to 410. That's a big change. It's easy to measure. Right. In the oceans, there is naturally a lot of carbon already there. Allergy and zooplankton. Right. It just naturally stores carbon actually in the form of bicarbonate, kind of like Alka-Seltzer. Okay. And so that natural carbon, the fossil fuel carbon that we're adding is a tiny, tiny fraction. So we're looking for a tiny change in a great big number. To do that, we need very accurate and precise numbers. And that's why up until the mid-1990s, we didn't really have the data that we needed to measure that man-made CO2. So in the 1990s, that became part of a program where we would go out on these research ships. So these are ships that are owned by the federal government. There are a dozen or so of them around there, 280, 300 feet. This is an example of one that we were on. And we set up basically a grid pattern across all of the oceans where we go east to west and we go north to south and just survey the whole oceans. And it takes one to two months to do each line to go across. So for example, we had one line that goes from San Diego to Hawaii, and then Hawaii to Tokyo, Japan. Each of those legs from San Diego to Hawaii took about a month, and then from Hawaii to Tokyo took about a month. And that's because we would go 30 miles, we'd go 30 nautical miles, and then we'd stop and we'd collect samples between the surface and the bottom. And we do that with these large bottles, these large sample bottles, like they're shown here. There are 36 of them on that package, which is called a rosette. And there's a computer in the middle of that. We lower that all the way to the bottom of the ocean. And then we close each of those bottles at different depths. And then we bring that back up on deck. And then we all stand around and wait our turn and we sample. So I would, those bottles hold 20 liters of water. And then I would come and take my 500 milliliter sample of water. And then I take that and take it into the lab and put it on an instrument called a coulometer that we would use to measure the dissolved interganate carbon concentration. That's what the coulometer looks like in the van. And so I would measure those 36 samples from the depth. And then the ship would move another 30 miles. And we'd collect another set of samples and I would measure it again. And you do that again. And again, the ship and my program, we would operate 24 hours a day, just constantly running samples. And we had to do this for 10 years. I wasn't out on every cruise, but I was out on far too many of them. You spent a lot of time at sea. We spent a lot of time at sea. I figured that over my lifetime, I've spent about five years of my life out on the ocean. Amazing. So this really was a unique data set and something that was not possible. It was quite expensive to go out and do all these samples. And of course, it takes a long time. And we're going everywhere from Antarctica to the Arctic and, you know, like I say, across all of the ocean basins. Then I had to pull all these data together and compile it into a database, make sure that the measurements we did in the Pacific were comparable to the measurements we did in the Atlantic and the Indian Ocean. Pull all that together and then calculate that small fraction that came from the man-made CO2. Right. We're going to dig into this more deeply. I'm told we have to take a break right now. First, for Sabine's with me here, I'm your host Ethan Allen in Likeable Science. We'll be back in one minute. Aloha. This is Winston Welch. I am your host of Out and About where every other week, Mondays at 3, we explore a variety of topics in our city, state, nation and world and events, organizations, the people that fuel them. It's a really interesting show. We welcome you to tune in and we welcome your suggestions for shows. You got a lot of them out there and we have an awesome studio here where we can get your ideas out as well. So I look forward to you tuning in every other week where we've got some great guests and great topics. You're going to learn a lot. You're going to come away inspired like I do. So I'll see you every other week here at 3 o'clock on Monday afternoon. Aloha. Aloha. I'm Wendy Lowe and I'm coming to you every other Tuesday at 2 o'clock live from Think Tech Hawaii. And on our show, we talk about taking your health back. And what does that mean? It means mind, body and soul. Anything you can do that makes your body healthier and happier is what we're going to be talking about. Whether it's spiritual health, mental health, fascia health, beautiful smile health, whatever it means, let's take healthy back. Aloha. And welcome back to likeable science here on Think Tech Hawaii. I'm your host Ethan Allen. Thanks for coming back with us. I have Dr. Christopher Subine here with me today in the studio from UH Manila, the Department of Oceanography, a researcher, acting associate dean. And we've been talking, we talked in the first half of the show about his research on how we were, how he goes and samples the water at various depths in a very systematic way all across the ocean. And he pointed out that the carbon makes, that we dump in the air makes up a good fraction of the carbon that is in the air and thus a change is easy to see. But the carbon in the ocean, of course, is sort of a drop in the bucket as it were. There's a lot of naturally occurring carbon. And so my question to you now, sir, is how do you tell the difference between carbon, I mean carbon is carbon, right? And how do you tell the difference from what was sort of naturally there, supposed to be there versus what we have added? That's a very good question. And one that we've struggled with, because like you say, carbon is carbon. And we want to know how much it has accumulated since the pre-industrial. We don't have any measurements from prior to 1800 that if we could have gone out and measured it then, it'd be really easy to just look at the difference. So what we do instead is we take advantage of another kind of interesting fact, which is that atmospheric carbon dioxide prior to around 1800 when we started burning fossil fuels was amazingly constant in the atmosphere. Since we came out of our last ice age, the last 11,000 years, carbon dioxide concentration in the atmosphere has been very constant at 280 parts per million. The ocean has 50 times more carbon in it naturally than the atmosphere. The only way that the atmosphere could be constant for that length of time is if it's in balance with the ocean. And if we know that the ocean is in balance with the atmosphere, then we can calculate how much CO2 should naturally be there, was there during the pre-industrial times. Right, a few thousand years of gasing and degassing. Exactly, it's all kind of settled in, it's equilibrated, and it's in a steady state. So then we go out and we do all our measurements and we look at the difference between what we measured and what we calculated should be, and those differences are the amount that's been added. And then the neat thing is with this new survey that we did, we went out then in the 2000s and we resurveyed the oceans and this paper that we just wrote is looking at the difference and now it's much easier. I measured it in the 1990s and then we measured it in the 2000s and we literally are just looking at the change between those two time periods. And you saw how similar those patterns were. That's a confirmation that my original calculations were very accurate because the patterns are consistent. Right, and you'd expect to see, as you were saying earlier, the downwellings and upwellings are going to produce different carbon signatures because of the very nature of them. Exactly. Excellent. So then we get, I guess, the question that's probably on everyone's mind is sort of, so what? So there's a little more carbon in the ocean. Who cares? But there are reasons we all should care, right? There are reasons we should all care. And there's kind of two main ones. The first one is when you talk about climate change and the greenhouse effect and global warming, that's only a phenomenon that's seen with the carbon dioxide that's in the atmosphere. So as long as the oceans are absorbing carbon dioxide out of the atmosphere, that's reducing the effects of climate change. In fact, we've seen that the oceans over the last 200 years have absorbed about 30% of all the CO2 that we've emitted, which means that there's 30% less climate change than we would expect to see if the oceans weren't here. So CO2 in the atmosphere now is about 410 parts per million. Without the oceans, it'd be more like 450 parts per million. And we'd see much more dramatic effects like more hurricanes and more intense hurricanes around Hawaii and more warming and so forth. So that's the first thing. And when I first started studying this, that was the key to what I wanted to understand and say, well, maybe we can enhance that. But then we discovered that we put so much carbon dioxide in the oceans that it's actually changing the fundamental chemistry of the oceans and that has an effect on marine organisms. Right. And by changing the chemistry, that is basically it's building carbonic acid in the ocean. Exactly. CO2 is what we call an acid gas. The carbon dioxide reacts with the water molecules to form carbonic acid. We call that ocean acidification. We're acidifying the oceans. And again, the oceans are pretty big and pretty have a good deal of capacity, but we are starting to make a noticeable impact, at least in some parts of the oceans, right? That's right. And particularly, we're seeing the impact on organisms that produce calcium carbonate skeletons or shells. So coral reefs, the white sand beaches on Hawaii, your clams and oysters and mussels, all these are affected by the acidification of the oceans. Right, because as the ocean gets more acidic, the shells are basically being... the calcium is being drawn out of the shells more or less. Right, it's more difficult for them to form their shells and skeletons. So they grow more slowly. Particularly for the young ones, I have a real hard time and we're beginning to see malformed ones. Ones that aren't surviving as well. Exactly. So for the oysters, for example, they're broadcast spawners, right? So they spit out their larvae that float around for a while and then at some point they start to form that calcium carbonate shell. That shell is what makes them heavy so that they sink out and then they settle someplace and then they start to grow, like the oysters that we're familiar with. The problem is, during that period, they're very sensitive to the acidification of the oceans and under high CO2 environment, they cannot form that initial shell. So they never sink out and so they just float around until they die and you get no new oysters. That's a very critical life stage for them. Right, and the oysters are a simple one example. You mentioned, of course, clams, but here around Hawaii and in the tropics, of course, we really are much more concerned with reefs, right? Exactly, the coral reefs. They protect us from storms. They provide tremendous economic value to the Hawaiian islands. Right, and they're referred to as the nurseries of the sea, because many, many life forms have their, from the stage, their young usually are in or around the coral reef. Exactly, and it's in particular, all those nursery grounds are based on that complex structures that are made from that calcium carbonate skeleton. Exactly, the coral reefs have a lot of spatial complexity to them. They allow a lot of different habitats within them. They allow a lot of shelter for smaller animals. So with ocean acidification, we, kind of, it's not a perfect analogy, but we kind of think of it kind of like osteoporosis, you know, where your bones get brittle and they break. You have the same sort of thing with the corals that they can become very brittle. They're not as strong, so then you have a storm, or you have, you know, a turst walking around on the reefs or a boat that runs into it, and it just crumbles and shatters much more than it would under normal conditions, and that's bad for the reef. Right, and then it also won't regrow, because, again, the coral polyps, when they're growing, they have to start that same cycle of the oyster, right, and begin to pull calcium carbonate out and put it together. Exactly. And under a set of conditions, they just, you know, you can't make the chemistry work. Right, and then we also see kind of synergistic effects that another major impact on the corals is coral bleaching, which is a warming effect, right? So when it gets too warm, the corals bleach, and that's bad for them, what we find is when they're already stressed from the ocean acidification, then when they bleach, they're more likely to die than under low CO2 environments. So those two kind of play off each other. Right, in a rather unfortunate, vicious circle, right? Yes. Yeah, because they can survive around or to a bleaching if they're reasonably healthy, and have a time to relax and recover. Right. But if they're already sort of sick and damaged, and plus there are other things too, getting back to your prior coherence, the plastics in the ocean, when plastics lie against coral, you tend to get more problems with the coral, but locally the coral is damaged by the presence of the plastic. Exactly. And that's what we're really looking to try and find solutions. The problem with things like ocean acidification or climate change is they really are global problems. They require a global solution that's rather difficult. So what we can do locally, though, is the corals, for example, are feeling the effects of a whole range of stresses, like the plastics, like excess nutrients in the bays from the runoff, like pressure from sunscreen and other tourists. What we can do is if we can reduce some of those other stresses, then they've got more energy reserves left over to try and recover from the bleaching or from the acidification. Right, exactly. Like most things, it's not just one single phenomenon. It's a whole slew of interrelated phenomena, stressing the coral in this case. And the more we understand about all those different stresses, the more we can manage for that and try and... Exactly. And the better the chances that we'll be able to save some of the coral, get it back. And if the coral goes, we have some very serious issues facing us in terms of much of the rest of the ocean. The collapse in a third of the protein, animal protein in Earth is sort of gone. Oh, yeah. And there's all kinds of other effects of ocean acidification that we wouldn't even think of, that carbonate the calcifiers are the most obvious one. But another one is we found that, for example, reef fish lose their sense of smell. They lose their ability to detect predators, which means that they wander farther away from their productive houses and they get eaten. So it sounds like we could probably talk for hours about this, but unfortunately I'm told we are nearing the end of our time. Christopher Sabine, I'd like to thank you for being here, but you've enlightened me and enlightened our audiences. So I hope I thank you very much for coming here. It's been my pleasure. Yes, indeed. And I hope you will come back and join us next week on another episode of Alakeable Science here on Think Tech Hawaii.