Can We Save the Great Barrier Reef? | Ep225: Dr Katharina Fabricius

Katharina Farbricius

I've now seen six massive bleaching events on the Great Barrier Reef. And when we had these back to back bleaching events in 2016 and 2017, and I was surveying how much coral we again lost. It was just awful. You could smell it. You could see this tissue of coral sloughing off, you could see this change from colorful, vibrant algae to just slimy matted algae and so on. It took me many, many months to sort of come to terms with ‘okay, that's our new reality. What can we do?’

Bryony Worthington 

Hello, I’m Bryony Worthington and this is Cleaning Up.  My guest this week is Katharina Fabricius an ecologist who has spent her career studying coral reefs around the world - we recorded in person in August at her home in Northern Queensland, Australia -  and delightfully we were accompanied by parakeets but from time to time you’ll notice them making themselves heard!  Katharina and I met a few days after the publication of the latest annual assessment of the condition of Australia’s Great Barrier Reef - a report which documents how a range of rapid changes are impacting the health of this unique and vast habitat. Katharina has written about the ‘seven sins of climate change’ and I wanted to ask her about the cocktail of inter-related risks that are affecting coral health and how bad things are right now. And on the positive side, as there are a lot of unknowns when it comes to the resilience of the species that make up the corals, we explore  whether it’s still possible to reduce the pressures and allow them to bounce back. Also Australian politics has also changed in recent years with the country emerging from the bleak anti science era to one where more attention and more resources are being applied to the issue. I hope you’ll enjoy the conversation. Please join me in welcoming Katharina to Cleaning Up. 

BW

Katharina, thank you so much for agreeing to come on Cleaning Up. It's very, very lovely to be here with you on Magnetic Island in Queensland, and I wanted to start like we always do, by just asking you to introduce yourself in your own words please. 

KF 

All right, thanks for having me. So I'm Katharina Farbricius. I'm a coral reef ecologist, and I grew up in Germany, but came to Australia in about 1988 because I really wanted to work on coral reefs. And the number of coral reefs in Germany is not that great. So it was a little bit of serendipity. I encountered the opportunity of work on the Great Barrier Reef, jumped at it while I was at university, and came over for six months. And that was about 30 years ago.

BW  

What was it that drew you to ecology first, and then also, why did you specialize in coral reefs?

KF  

I think I've always really cared about conservation, and even early on, I was interested in birds and insects in Germany. But working on the North Sea, or the coral reefs, for some reason or other coral reefs won out. And yeah, just the enormous diversity, the enormous complexity of coral reefs, attracted me from early on, and I am just feeling very privileged to spend my life looking at them and trying to understand a little bit more about how they're functioning and how they're faring under these changes that are so alarming, and so fast.

BW  

And so now you're currently a principal investigator at AIMS. Do you want to tell us a little bit about what AIMS is?

KF  

So AIMS is our short name for the Australian Institute of Marine Science, and it's really focusing on the tropical marine estate of Australia. So we're working on the east, the north and the west coasts of Australia. And a very strong focus is coral reefs, but also mangrove sea grasses and other ecosystems. I'm working in a program that is called the healthy Great Barrier Reef. So our focus is very much trying to understand how and what we can do to keep coral reefs healthy, what are the main pressures, and how are the coral reefs changing under human use and under changing conditions.

BW  

So we're here in August, in Queensland, and just last week, there was a report published about the Great Barrier Reef. Do you want to just introduce that report, perhaps by explaining how vast the Great Barrier Reef is? I mean, it's one of the largest natural structures on the planet, right?

KF  

So the Great Barrier Reef is over 2,000 kilometers long. It's literally almost the size of California, the size of Germany, three times the size of England. So it's a vast area. It contains coral reefs, seagrass meadows, large inter-reefal areas. So it's an enormous diversity of ecosystems, and within those ecosystems, a quarter of all the marine species are found on coral reefs alone. So it's very, very special. In Australia, the Great Barrier Reef has been monitored using the same methods for 39 years by the Australian Institute of Marine Science. And so each year we are reporting how the reef is faring under the increasing pressures from climate change, from poor water quality, from storms and from outbreaks of coral eating starfish called crown-of-thorns starfish. And in the beginning, those changes were relatively unnoticed. But in 2012 we, for the first time, really looked at how the coral reef is changing and faring. And Glenn De'ath was the main investigator of that study. And we found, at that time, over 27 years of observations, coral cover has reduced to less than half of what it was when we started observing coral reefs. So it went down from 27% coral cover, which is basically how much coral you find on a reef and how much spare space, down to less than 13%. So more than 80% of the coral reefs were not covered by corals any longer. So that was a very politically loaded discovery and made it around the world, and probably caused more attention to reefs globally than any other study done in that decade. And since then, the annual release of the changes in the Great Barrier Reef are always anticipated with great trepidation. This year, we've seen the greatest sudden decline in coral cover that we've ever recorded, but after a period of relatively good recovery. So reefs, after the low times in 2012, slowly crept up to relatively good levels again, because we had a period with very few storms and and bleaching events were not as bad as they could have been. And crown-of-thorns starfish started to be managed a little bit. So the cover started creeping up again. And then in 2024 we had the most widespread, most severe bleaching event that has ever been recorded in the southern Great Barrier Reef. The southern third has lost more than a third of its coral cover. The North has lost a quarter, and the center fared a little bit better. A third of the corals got lost in the upper, upper areas of the Great Barrier Reef.

BW  

As I understand it, this is a combined effect of different impacts on the reef. So you've published a report about the seven deadly sins of climate change. Do you want to just tell us a little about what those seven intersecting threats are for the reefs? 

KF  

So the seven sins of climate change are climate-related disturbances. We typically talk about global warming, but there's much more to it. The greater energy in the air is causing marine heat waves. So it's not just the temperatures rising up, but we've got these prolonged, more intense and more frequent heat waves, and that's the main killer for corals at this stage. The problem is that corals are incredibly sensitive to high temperatures. They're living on the upper limit of the temperature tolerance, and only a one degree warming above the long term maximum for a few weeks is enough to trigger what we call coral bleaching. Now, coral bleaching is a phenomenon that basically describes the corals turning white. Corals normally have the pigments because little algae are living in their tissue. And these little algae are providing the coral with the sugars and the energy that the coral needs to live, because tropical coral reefs tend to be quite poor in nutrients and energy. So this living together between the animal and the plants means both are having a better system. We call it symbiosis, and it's like our gut bacteria. We're living in symbiosis. There's a lot of bacteria in our guts. Plants are living in symbiosis with fungi that are feeding the roots and therefore feeding the trees. And similarly, corals are living in symbiosis with those little algae that are doing photosynthesis, feeding the corals with sugars and making the corals really thrive. And those algae, this balance between animal and plant, is highly temperature sensitive. When corals are experiencing marine heat waves, they're expelling those little algae, the tissue turns dark white, and typically either succumb to diseases or starve, or if the heat wave disappears more quickly, they can recover. So that's species dependent. And it depends how intense the heat wave is.

BW  

So this average global temperature rise is being felt and experienced in particular places. In quite extreme heat waves, the sustained increases in temperature, they're well above the average, and that's causing these bleaching events where the algae are being expelled. But there's also other compounding factors, isn't there?

KF  

So the warming means animals tend to move more towards the poles, because the zone where they feel best is shifting towards the poles, and those temperature zones in the Great Barrier Reef are presently moving at about 200 kilometers per decade. So that's very, very fast, and many organisms cannot keep pace with that movement. So warming temperatures, because most organisms in the ocean, their metabolism depends on the outer temperature. They don't control the temperature, as we do, but they depend on the external temperature. That means, if it's very warm, fish are just digesting their food more quickly and need more food, or all the functions are accelerating with swarming temperatures. You find this synchrony between spawning and food availability breakdown. Global warming, on its own, is already causing massive shifts. But on top of that, you get these heat waves which are causing this increasing stress level, like for humans as well. I mean, we know the heat waves in cities are unfortunately causing a lot of mortality already. The same is happening to corals. So heat waves are really the killers. Warming is causing more gradual shifts in communities.

BW  

And then, of course, you've got acidification as well. So you've worked a lot on that. You want to talk to us about that one of the Seven Deadly seven deadly sins?

KF  

That's right. One topic I'm really concerned about is ocean acidification, which is explained by the fact that the atmosphere and the ocean are in equilibrium. So because we are blowing more CO2 into the atmosphere, that enters into the ocean, combines with water molecules to form carbonic acid, and that makes the sea water slightly less alkaline, equals more acidic. Corals and many marine organisms all around the world form calcareous skeletons to protect their bodies. And like chalk and lime just don't go together, corals are not able to grow as fast or reproduce as effectively in more acidic conditions. Now, oceans will never become acidic. They are naturally alkaline, but they're less alkaline now than they used to be, and the forecast as such, is that coral reefs are reaching the limit of where reef development is possible in the next few decades. And in the geological past, when that happened, we saw gaps in reef formation that lasted over a million years. So we had five mass extinction events in the geological past. Many of them are now very strongly linked to high greenhouse gasses, like volcanic eruptions or other forms of sudden spikes in C02. And we are doing it now through the burning of fossil fuels. So we're very concerned that the high CO2 is severely compromising the ability of coral reefs to persist. Because we are reaching that threshold that has not been exceeded in the geological past, that coral reefs simply cannot go.

BW  

And if someone's listening to thinking, well, we've had five extinction events. You know, six is maybe on the way. But why does that matter? Or why are reefs such an important habitat?

KF 

So mass extinction events at a geological scale happen very rarely, like they happen once every tens of millions of years. We had five in the whole geological past since the beginning of life. And as a human, I care about human time scales, not geological time scales. Yes, there will be some new forms of life evolving in another 10 million years, but what do we care? Now is what we are leaving behind to our next generation. The evolution of biological diversity takes millions of years. We've got the most biologically diverse marine ecosystems on our doorsteps, and we are the custodians. We've got the technology to fix our CO2 emissions and protect biodiversity. So I think it's just morally inexcusable to not do what we can to protect that biodiversity in the oceans, on land and and therefore, as a human being as well.

BW  

I certainly would have thought for non-Australian reefs, you've got populations living next to the reefs who are dependent on the fish stocks. And so there's not just a moral case, which I completely agree with, but there's also a kind of human economy problem.

KF  

Yeah, totally. So coral reefs are supporting — we don't know the exact number — but some estimates say about 500 million people for their livelihoods, and that's for protein, so really food security, for income from tourism, and also coastal protection. So it's estimated that coral reefs are worth more than $30 billion US per year in terms of ecosystem services. And if you're losing those ecosystem services, we're contributing to global inequality. More than 100 countries have coral reefs, and probably only four out of these 102 countries that own coral reefs, are in high income economic conditions. The others are low to medium in economic status. So I feel in Australia, we've got the responsibility to contribute the science to help protect reefs in lower income countries as well.

BW  

Yeah, and you touched on there — apart from them being very productive in terms of proteins and fish, they've also got this protective element where they help reduce storm damage and flooding. 

KF  

Yeah. So both coral reefs and mangroves are incredibly important in reducing the problem of storm erosion of coastal areas. A large proportion of humanity is living in coastal areas. And particularly in the tropics, I think the number is 70% or thereabouts. So with sea level rising and accelerating its rise, it is really important that coral reefs are forming barriers that prevent storm waves from eating into our coastal areas and accelerating erosion. And they're doing it very, very effectively.

BW 

But then that increased energy in the weather system is also having a knock on effect on the corals themselves, right? Because you've got more storm damage and more increased rainfall, which is, I had only learned this on this trip, that when you have these big precipitation events, you have this runoff of fresh water and sediment, and that can then affect the corals’ resilience.

KF  

That's right, yeah. So that's another one of those scenarios of climate change — the more episodic and more severe oscillations between severe rainfall events and droughts. Only six months ago, we had almost two meters, over two meters of rainfall here within 48 hours. It was just enormous. And those big floods are happening quite often and happening more frequently, and we've got a high certainty that the intensity of droughts and the intensity of floods is increasing. Now the worst thing is a drought breaking flood, because there's no vegetation to keep the soil in place, and at the same time, the floods are basically carrying all those sediments and nutrients that we need on the land to grow our food into the ocean, where they damage the corals. And corals are very sensitive to sediments and nutrients and pesticides, and find it more difficult to recover from disturbances in areas where the water is turbid from all the mud and the sediment on the ground. The Great Barrier Reef is very sensitive to sedimentation because it's a shallow continental shelf, so the sediments that are coming down there, staying in the system, get churned up and get resuspended over and over again. So water remains turbid for prolonged periods of time, and we talk about four to eight months that the water remains cloudy until eventually the particles are flushed out and you're back to higher water clarity.

BW  

So have we covered all the seven sins now? Or how are we doing?

KF 

I think we're still talking about changes in cloudiness and windiness, which are also contributing to bleaching events. So we are probably getting more intense monsoons, which means more cloud cover in some areas, but also less cloud cover and more intense sunshine which contributes to bleaching as well in the Southern Barrier Reef, so altered currents less potentially changes in upwelling of nutrient rich, cool waters. So currents, windiness and cloudiness are also issues that the reef has to deal with. So it's a whole cocktail, and each of those seven climate impacts are changing the system in different ways, but they're all cumulative. So one is on top of the other. That means we're really posing enormous challenges for coral reefs. It's already started, we can measure it, and and it will only accelerate. We’re at the beginning of the curve.

BW  

That is all very concerning and quite gloomy. I know we should be concerned, and I'm not trying to diminish this at all, but could we talk a little bit about what you've observed in terms of corals’ resilience, or what nature can itself do to help itself through this period?

KF  

Happy to do so because, yes, I mean, for example, the Great Barrier is 2,000 kilometers long and three degrees warmer in the north than in the south. So there is inherent resilience. We have seen recovery after big storms. We've seen recoveries after the big bleaching events, and we are seeing that some of the organisms are moving with the moving temperatures. So coral reefs have always faced disturbances, and they are quite resilient systems that can bounce back. But our concern is that the disturbances are happening so quickly now that they just don't have enough time to recover. So for the last five years, AIMS has been pushing the science to understand how reefs can be helped. To assist evolution, assist adaptation, and assist recovery. That may be through moving larvae from the warmer areas to the cooler areas. That may be through breeding more temperature tolerant corals, that may be through understanding the technologies to upscale such activities. That's through social science to understand the concerns of people and get them on site to to really have the buy in of the population, see how traditional owners are feeling about it, and see how the community is there to support it, and understand the finances of the housing, because it's not going to be cheap. Like all remediations, it's cheaper to prevent than to assist any adaptation, but nevertheless, we need to understand how to do it. Restoration has been studied, and restoration ecology is a 20-year old discipline or so. But we are only just starting to apply it to the marine world. And so we are feeling we can learn enormously, and we have to do it now before it's too late to see what we can do to help coral reefs to live through what the next decades are bringing.

BW  

Yeah, and is this something inherently there's other, some forcing factors that are positive, so this symbiosis, that the algae and the coral living together, they have quite rapid evolutionary cycles, don't they, compared to, say, mammals? Is that something we can hope that there'll be more genetic diversity because of that?

KF  

It's possible. I mean, corals are long lived organisms. Many of them can be tens of years old. Some can be hundreds of years old. And so generation times are relatively slow, but maybe it is possible that the symbiosis is shifting. 10 or 20 years ago, we thought they were very stable. There's these symbiosis and only what the little corals have taken up will remain with them throughout their lifetime. But now we have seen evidence that symbionts can shuffle, so the more heat-adjusted ones may bloom within the coral, whereas the others decrease in abundance. So there is some reason for hope that those conditions are changing. There is certainly very clear data that reefs can bounce back from disturbances, and there are some signs that adaptation is happening naturally. Like the first bleaching winds have caused enormous damage, and I'm just hoping to see that the last bleaching winds, although they've been far more severe, eventually just weeding out the most sensitive specimens and allowing the other ones to spread. But that means also reducing the other pressures on those surviving corals, which are probably the most heat tolerant corals we've got. So we need to reduce the runoff of nutrients, which feeds the crown-of-thorns outbreaks and so on.

BW  

And crown-of-thorns being the invasive starfish, is that right?

KF  

That they're native to Australia, so not invasive in terms of being alien, but they're forming these enormous population outbreaks, like locusts eating whole forests. Starfish eat coral, and they can form these outbreaks where all of a sudden, you've got a million of them on the reef. They can be up to 70 centimeters in size, and they just eat enormous quantities of coral.

BW 

And they're faring better in the warmer temperatures, or they're just something about?

KF  

They're faring better in areas of high nutrients, because their little larvae are feeding on these algae in the water. So more fertilizer, more algae, because algae are plants, fertilizer fertilizers plants, and because they're filter feeders, they've got more food to eat. And the survival as larvae is greatly enhanced when there's more nutrients in the water. That nutrient may be just natural upwelling of nutrient rich deeper waters, or it may be the runoff of fertilizers from cane fields into the into the ocean. 

BW  

And so, you mentioned the cane fields. So this part of Australia is a tropical area, but it's sustained by running some very large scale plantations of cane sugar and bananas. And so that's receiving nitrogen as a fertilizer and that's running off?

KF  

Yeah, and because we've got these episodic, very intense rainfall events, it's very hard for the farmers to keep the fertilizer on the ground. Some of the nutrients are washed off directly. Others are bound to the soil. And in overgrazed areas, we're getting a lot of soil erosion, and they bring in a lot of nutrients as well, and stuck to the soil particles?

BW  

Because the soil is quite iron rich, is it?

KF 

The soil is iron rich, and also compared to the very, very nutrient poor oceans, it carries organic and inorganic nutrients.

BW  

Okay, so the starfish are doing well, but that's not good for the coral.

Michael Liebreich  

Cleaning Up is supported by its Leadership Circle. The members are Actis, Alcazar Energy, Arup, Cygnum Capital, Davidson Kempner, EcoPragma Capital, EDP of Portugal, Eurelectric, the Gilardini Foundation, KKR, National Grid, Octopus Energy, Quadrature Climate Foundation, SDCL and Wärtsilä. For more information on the Leadership Circle, please visit cleaningup.live. If you've enjoyed this episode, please hit like, leave a comment, and also recommend it to friends, family, colleagues and absolutely everyone. To browse the archive of over 200 past episodes, and also to subscribe to our free newsletter, visit cleaningup.live.

BW  

They are so productive, corals, aren't they? Do you want to talk about how they have these balloons where they sort of send out all of this sort of fertile. Well, you tell the story, because also isn't that helping? As there's a current that takes that south from here?

KF  

Yeah, so corals are animals, but they sit attached to the ground like plants do. So in order to reproduce, they're releasing their gametes, the sperm and eggs, into the water column, where fertilization happens. Because boys and girls can't get together. Those gametes form larvae, and these remain in the water for a number of days. Depending on species, it can be five days, it can be 10 or 20. And during that time, they're rafting from one place to the next, and it can be up to tens of kilometers that they're migrating. Some species have larvae that are staying with mum for a long time, and then plonk in the vicinity. But many of them are rafting for long distances. And typically, many of these larvae that are produced are rafting towards the south, towards the cooler areas. So that helps with adaptation towards warming conditions as well. And I think the situation is becoming more complex in the far north, but that's work I'm doing at present. In general, those larvae are settling down, if there's not too much sediments on the ground, they get these tiny little coral babies sitting on the ground, hoping that they're not getting covered in sediments, and eventually, sort of budding new polyps and growing like a plant and forming branches or mounds or plates or whatever size the particular species inherits. And those corals are the builders of coral reefs, so they've got carbonate skeletons. Those skeletons allow them to grow up and into the water column, and those skeletons are the hiding spaces for all those reef associated organisms like shrimps and crabs and starfish and you name it, worms and things. We literally have a million, probably a million species of organisms associated with coral reefs, and that's an enormous number, and they all depend on healthy corals. Because corals are forming the habitat, like trees form the habitats for birds and so on. So we need to keep the corals healthy. But in many cases, there are more complex interactions, like if we have healthy fish populations, they keep the algae down, which compete with corals for space. If you keep the nutrients on the land, they don't fertilize the algae that are growing on the ground and compete with corals for space. So it's all in balance. It's all connected. It's all very complicated. And 30 years later, after working on coral reefs for more than 30 years, I'm still amazed how many different environments coral reefs really can function in, because they're just amazing.

BW  

And that's why you've studied them for so long. If it's not too difficult a topic, could I just turn to your personal response to what you've witnessed? That's a lovely sense of potential there, that there's potential resilience, that we could celebrate about corals. But the political context that we're in, you probably have seen, like everybody, the Trump statements that climate change isn't real. We seem to have come backwards quite a long way. How does that feel to hear that when you know you're seeing with your own eyes the changes?

KF  

I'm really concerned about those changes. So on a personal level, I've seen the first big bleaching event in 1998. At that time, it was a curiosity. We didn't understand what caused it. I mean, basically a whole coral reef turned pastel colors — pink and blue and yellow and white, and then they start dying. So I reported it at a conference, and none of us had seen any of that before at large scales. I've now seen six massive bleaching events on the Great Barrier Reef. And when we had this — back to back bleaching events in 2016 and 2017 —  I was surveying how much coral we lost. It was just awful. I mean, all of us were really… you could smell it. You could see this tissue of coral sloughing off. You could see this change from colorful vibrant algae to just slimy matts of algae and so on. It was just absolutely awful. And I really burnt out at that time. And it took me many, many months to sort of come to terms, ‘okay, that's our new reality what can we do?’

BW  

And during that period, where was Australia, the Australian Government, where were they in terms of acknowledging the problem?

KF  

For a long time, climate change was a very politicized topic, and the government of the day just did not acknowledge it existed. They ignored all scientific evidence and basically backed industries. And I found, yeah, I mean, many of us found that very, very difficult to take. And now we are seeing a resurrection of those beliefs. I mean, even when people talk about, ‘I believe in climate change,’ it’s scientific facts, it should have nothing to do with beliefs. It’s such strong evidence that things are changing very, very rapidly. And in going back into the world of religion and beliefs, it’s just ignoring all the effort that went into trying to help humanity and ecosystems to live into the future. It's just so short-sighted. 

BW  

There was a period when it was particularly bad in Australia. Do you feel like you've lived through that now and you're coming out the other side of it? Or is the Trump effect having, well, the Trump effect seemed to have returned a sort of left leaning government, so center-left government. So in a sense, it's helped. But is there a contagion of this return to an ideological view that climate change isn't real? Or if it's real, it's not human?

KF  

Yeah, apparently, the population is way ahead of some politicians, most people in Australia are very concerned about climate change and want to see action against it.  And the uptake of rooftop solar is the highest in the world. So I doubt we'll ever revert back to systemic climate denialism, or at least I hope.

BW  

I mean it’s possible, but yes, the evidence so far is that Australia is holding on to the facts, and it's not reverting. Is the government of the day taking this issue now more seriously?

KF  

I think the government of the day is seeing the opportunities that a change in energy provision is bringing, so in terms of switching over to more renewable energies, the government is leading, and that has been a very rapid turnaround. They've been at the helm now for four years, roughly, not even, so they've achieved a lot. Australia is still producing a lot of fossil fuel and exporting it and part of our transition plan at this stage is still the use of gas to fill the gap between switching off the old and really unreliable coal fired power stations and the full amount of renewable energy, but most of our gas is being exported. Not, as far as I can tell, to a financial great benefit for Australia, because royalties and taxes are not high. But, yeah, my expertise is coral reefs and going into all these policy areas is probably not…

BW  

Yeah, perhaps we could talk instead about what the Australian government's attitude is towards reef conservation. Is it making enough research money available? Is there a way in which perhaps the people causing the impacts are paying for some of this? Is there a policy around actually investing in some of these solutions we talked about?

KF  

Yes, the government has put a lot of money into improving water quality. So that's been an area I was fortunate to be working on water quality for more than 10 years. And during that time, we saw 100% turnaround between absolute denial that this little bit of sediment and nutrient running off the rivers can possibly not make a difference for the reef, to accepting it's a major challenge. And now the investment into regional solutions to improve water quality have been substantial, so it's not one size fits all. Different measures are effective in different places, and there's a lot of learning to be done. What could be best management practices and what works for the sugar cane in the dry tropics is different to what works best in wet tropics and so on. So depending on soils and climate. There's a lot to be learned, and the government is supporting both the research and the adoption of better management practices, but the climate is becoming more extreme, so we are facing an uphill battle to some extent, and we really need to accelerate. We also need to accelerate the understanding of how adaptation can be supported, because we really only started five years ago on the topic, and that funding at this stage is a little bit of a stop start.

BW  

Let's go back to some of these interventions that we could take. There's the Coral Ark project that I know you're involved with, which is to try to hold on… like a seed bank for the corals. How much store could we put in that?

KF  

The Coral Ark is protecting species or protecting genotypes, really. So the idea is to keep corals alive, almost one of each species, in distributed aquaria around the world, which obviously costs energy and it is a desperate measure to keep species alive through the time when we hope it'll be a climate overshoot. And then towards the end of the century, come back to a little bit more normal conditions. Who knows? You don't know what climate scenario will play out. If the more pessimistic scenarios play out, the oceans will be too acidic to do much. But if you're in one of the more hopeful and more optimistic climate scenarios. Yes, we may be able to bring back some genotypes and do rewilding of coral reefs. So not only the most resilient corals will be out in the ocean, but we may be able to plant some of the more sensitive species that were kept in an Ark. But these are desperate times. I mean, at that time, we are really trying to preserve ecosystems. As I said, there are millions of species involved, and all of them are interacting to some extent. At this stage, protection, in my mind, is more important than these artificial situations. But once we've lost the genotype, it's gone.

BW  

What you've explained to me before is that the nature of the corals will change, that there'll be a selective process where the most resilient will survive, and it's more the sort of brain corals, or the spherical corals that will. So the look of the reef and the contents of the reef could just change dramatically?

KF  

And they will, no matter what we do. Reefs in the future will look different to what they look today. Reefs today already look different to what I've seen in 1988 when I started working on coral reefs. So I mean, we are losing color and structure and shark populations. There's so many things — marine turtles — that are going down. Nevertheless, the reefs are still quite beautiful in some places and definitely worth preserving. So I'd really hope to continue fighting for it, to do what we can do. And those restoration ideas, I mean, some may sound a little bit far fetched, like the Ark, and others are trying to breed corals that are more heat resistant and then release them in the millions to the reef. If they're successful, they may produce millions of offspring themselves. And so if we overcome a few bottlenecks, and that's my role, to some extent, in this restoration space, is to understand the ecological bottlenecks. So for example, we're using photogrammetry to see how fast coral reefs are changing. How fast are coals growing? We still don't know whether corals are faster inshore than offshore, in north to south. And now we've got the tools to understand those dynamics, those population measures. How long do they live? Where do they get damaged? How fast do they recover? So we're using new technologies to understand those dynamics of the reef, to understand which reef has what type of bottleneck in terms of recovery. There's no point in bringing lots of larvae from the north to the south if there's a lot of sediment on the reef and the larvae just can't settle. Or, if the bottleneck is survival of the little corals because there's too many algae, then maybe we need to do something about the fish, rather than throwing more coral at the system. So understanding the ecology, understanding which species have what type of environmental needs, helps making those restoration activities more effective — more cost effective, more ecologically effective. And that's where I'm hoping to be able to make a little bit of a difference these days.

BW  

You've also studied areas where there's much higher concentrations of CO2 in the water, or lower alkalinity. And so is there potential there as well for us to learn what can adapt?

KF  

I'm much more pessimistic about ocean acidification than adaptation to warm temperatures, because in areas that have high CO2, the work I've done was at volcanic seeps where carbon dioxide gas was bubbling out of the sea floor. And so we used those like natural laboratories to see what those corals who grew in high CO2 environments, how they're faring and how the ecosystem is changing in these high CO2 conditions. And what we found is that certain types of coral can, in high CO2, but they typically are the mounding corals, which are not very good habitat for, for example, crabs. Crabs can handle high CO2, but they need the habitat and so all forecasts from laboratory experiments, where all the crustaceans are probably okay, but from this field experiments, we learned those crustaceans are the first ones to go because the habitat is gone, not because of the physiology. So understanding the ecosystem, it was a lot of fun to work in these natural laboratories, like a time machine. You could say, ‘Okay, this is today. This is how it will be in 20 years time. This will be in 50 years time. And we could look along those gradients.’ And we had three of those gradients in both directions. So six gradients to see what is consistent and how the ecosystems are likely to change with increasing CO2. because everything else was the same. It's just highest here, definitely for decades, probably for hundreds of years, maybe for thousands of years. And so yes, coral reefs had still existed, but really, almost monocultures of these really tough mounding corals up to a certain point, and we call it pH, to the level of alkalinity of pH about 7.8. Today we are at pH 8.1 and we've already lost one point 0.1 pH units. It doesn't sound like much, but it's on a log scale, so another loss of 0.2 pH units is quite possible. And that means, yeah, that would be the end of reef development.

BW  

And that is one thing that, no matter how kind of a climate denier you might be, you can't deny that the pH of our oceans is shifting, right?

KF  

That's just pure physics, pure chemistry. Yes, I mean, that is happening. We can measure it, we can show it, and we can very easily determine the thresholds for certain organisms, where they can live and where they can't live. You've got vast areas of the ocean where the foundation of the food webs are calcareous little algae, and we know those algae are sensitive to CO2. We've got vast areas in the Antarctic with so called sea butterflies, an important part of the food web. They've got calcareous snail shells, even though they're in the water column. And again, they're highly sensitive to CO2.

BW  

I don't think I've heard of sea butterflies, so they’re a type of mollusk?

KF  

Pteropods in scientific language, and yeah, they're important food for whales. And krill are affected by high CO2 as well. So again, the bottom of the food web. 

BW 

And when it comes to acidification, whereas there are some interventions that have been proposed to try to brighten clouds or try to increase reflectivity, when it comes to the pH balance, it's happening at such a scale, it's almost unimaginable to think we could intervene to bring that back, right?

KF  

It is, in my mind. I mean, some people are talking about enhancing the ocean with alkalinity by grinding up rocks and releasing them into the ocean. But again, think about the scales, think about the additional trace elements that would come and cause some unwanted, harmful algal blooms or whatever. So it certainly is not just this neutralization of the acid. It would introduce all sorts of additional problems. So at this stage, no, there's no easy cure for ocean acidification, other than preventing emissions.

BW  

The parts per million. So that's that classic Paris Agreement target of neutralizing. So the sinks are healthy and the sources are reducing, so that we keep the parts per million as low as we can.

KF  

And I mean, every gigaton of CO2 is measurably changing the ocean. I mean, assume even distribution. We know what it does to the ocean, because it's pure physics. At the beginning, it mostly affects the upper 200 meters, so the surface ocean. Eventually it gets mixed in and is also affecting deeper areas. But again, if we clean up the air, within a very, very short period of time, the ocean will release CO2 back into the air and reduce the acidification issue, because the air and the ocean are in equilibrium. And the ocean is really providing us a service, they're taking some of the CO2 out. About a third of the CO2 we emitted is kept by the ocean, but it also makes it a little bit harder, once we reduce emissions, the oceans will de-gas to some extent. And that, again, it takes the geology and the plants to take in those additional CO2 until some CO2 gets taken into the deep ocean and buried in the deeper areas.

BW  

From my understanding, the land-based sinks up, as long as they're not burning down and being subject to desertification. They are responding to elevated CO2 and storing and growing, you know, the greening is happening. So we've got to focus on keeping the sinks healthy. Well, Katharina, I'm sitting here thinking you've spent your life doing this monitoring, so when you get up on a Monday morning like today, what's giving you hope? What do you think? Okay, humanity has got these tools, or is there something that you know that that you can see on the horizon that's going to be helpful?

KF 

Oh, hope is a funny term. In my mind, society is in the right space. In my mind, we need a fundamental change in some structures to allow people to live the simple, friendly, healthy, social life that most people are striving for. So my main concern is cooperation, or greed at this stage. Of course, what gives me hope is we do have the technologies to reduce the production of  CO2 from production of energy. It does exist. It's cost effective, so let's get on and do it at the same time. The loss of biodiversity is irreversible at timescales of millions of years. We also need to keep that in mind at the same level as focusing on climate to allow our ecosystems to be as healthy as possible, to take in the CO2 again, to create those equilibria that we are striving for and, I mean, look at this. What gives me hope is also living here. Because, yes, we're seeing climate extremes. We're seeing more intense storms, these big floods and these heat waves. But nature can be quite resilient, and so I hope, even if they don't bounce back in exactly the same shape and form as we used to, that after a while new forms of biota will establish and support humanity and livelihoods as we know them today.

BW  

During this trip, I've been in northern Queensland, where it does feel like the land that time forgot almost. The rainforests are incredibly diverse. You've got the reefs and the ocean systems. And then I've also been reading about microbial biology and how that's helping them, it obviously helps the reefs. Over the longer timescale, do you feel that nature has this kind of inventiveness?

KF  

Nature will recover. It will recover. It may take thousands of years. It may take tens of thousands of years, but from a human perspective, that's obviously not fast enough. We are causing changes that are faster than most geological changes, definitely faster than the onset of ice age and so on. My dad was a geologist, so that instilled in me some longer term perspectives, to some extent, which contributes to my hope. But that's probably a little bit cynical. We do care what's happening today. We do care what's happening in the next 50 years. And microbes have the advantage that their generation time is incredibly short, so they can create offspring that are better adapted to a new environment than they are themselves. So yes, it's an area we don't know anything about in the oceans. Microbial ecology in marine systems is very much in the beginning. What do fungi do? We do not know. Some bacteria, a little bit. We know a very little about viruses. We know hardly anything about fungi in the ocean. They do exist, but what do they do? Who knows? Maybe they're saving us all.

BW  

Yeah maybe, or maybe not. But I suppose the point here now is that, as you said, society is perhaps becoming more aware of this as an issue. And maybe the technologies that we've developed, the monitoring tools that we have, the data and modeling capabilities, if we put our minds to it, I feel like this is this generation's challenge now, is to really focus on those tools we've built and helping preserve our  home, right?

KF  

That's right, and roll them out really quickly. Really put our energy and our thought and our creativity into it. Because, it is the challenge of our time. We can do it. We've got an enormous capacity with computing and AI and these technologies. We've got our tools now to scale up to do it properly and to have a lighter imprint on society and on the environment than we used to do.

BW  

Thank you once again for agreeing to come on Cleaning Up. I very much enjoyed being here in your wonderful paradise home. 

KF

Thank you for the opportunity. 

BW

So that was Katharina Fabricius, recorded in August during a trip to Australia to visit my family. As usual, we'll put links in the show notes to relevant episodes and background information, including Katharina's Seven Sins of Climate Change paper, the book about microbes that I've been enjoying, and our recent episode with Helen Czerski, which also focused on the health of our oceans. Our thanks, as ever, to Oscar Boyd, our producer, to Jamie Oliver, our editor and the rest of the talented Cleaning Up team and our wonderful Leadership Circle members who make these podcasts possible. And thanks to you for listening. Please join us at the same time next week for another episode of Cleaning Up.

ML  

Cleaning Up is supported by its Leadership Circle. The members are Actis, Alcazar Energy, Arup, Cygnum Capital, Davidson Kempner, EcoPragma Capital, EDP of Portugal, Eurelectric, the Gilardini Foundation, KKR, National Grid, Octopus Energy, Quadrature Climate Foundation, SDCL and Wärtsilä. For more information on the Leadership Circle, please visit cleaningup.live. If you've enjoyed this episode, please hit like, leave a comment, and also recommend it to friends, family, colleagues and absolutely everyone. To browse the archive of over 200 past episodes, and also to subscribe to our free newsletter, visit cleaningup.live.