Welcome everyone to 100 Climate Conversations. Thank you for joining us. The series presents 100 visionary Australians that are taking positive action to respond to the most critical issue of our time, of course, that’s climate change. We’re in the Boiler Hall of the Powerhouse museum. Before it was home to the museum, it was the Ultimo Power Station. So built in 1899, it supplied coal powered electricity to Sydney’s tram system and that lasted right the way into the 1960s. In the context of this architectural artefact, we shift our focus to the innovations of the net zero revolution.

I’d like to start by acknowledging the Traditional Custodians of the ancestral homelands of the Gadigal people of the Eora Nation upon which we meet today. We respect their Elders past and present, and recognise their continuous connection to Country, never ceded. My name is Nate Byrne. I am thrilled to be hosting 100 Climate Conversations throughout Sydney Science Festival. Today I have for you an amazing guest. The wonderful person sitting next to me is Maria Palacios, who I have the absolute pleasure of nerding out with today. She’s a marine ecologist, a project manager and science communicator based at Deakin University’s Blue Carbon Lab. She’s got over a decade of experience in research in marine and coastal ecosystems and established the award-winning Blue Carbon Citizen Science program. We are so thrilled to have her join us today. Please join me in making her feel very welcome with a very warm applause for Maria.

You grew up in Cali in Colombia, over 100 kilometres away from the coast. Your entire science love is to do with the ocean. How?

Yeah, that’s a good question. So, as you mentioned, I grew up in Cali, four-hour drive from the Colombian Pacific coast. And I think my connection comes actually because my parents were very keen divers. So, since I was very little, they’ve taken me to the ocean to snorkel, to check out the coral reefs and see what’s happening there. They loved the ocean so much, they actually named me ‘Maria del Mar’ which means ‘Mary of the Sea’. So, I guess it was meant to be, I’ve always had that strong connection. That was how I developed my passion I guess, my interest for coral reefs, but it actually didn’t happen that I wanted it to become a career until later on. It was a holiday that my parents sent me for summer, sort of summer camp, to my uncle and aunty, and back then they were doing a PhD in the United States. So, I hanged [sic] out all summer visiting the research stations, helping them collect critters in the wetlands and hanging out in the tanks. So, I think that I thought then, ‘Oh, this is amazing. I definitely want to make a career out of this.’

Okay, so you did your undergraduate in marine biology. You spent three months on the beautiful Great Barrier Reef for your PhD. What brought you to Australia? I mean, there are oceans everywhere.

I first did my bachelor in Columbia and then I, for the first time, started working with coral reefs and I thought, ‘Oh, if I really want to get to understand these ecosystems, I need to go to the best place on Earth to study coral reefs.’ And that led me to the Great Barrier Reef. So, I went to James Cook University in Queensland, and I spent lots of time up north in Lizard Island just studying the behavior of coral reef fish. So, I spent I think almost one year at the research station in total and just basically studying the behavior of fish in the lab and in the tanks.

So coral reefs are your first love?

Yes, 100 per cent.

But that’s not the only thing you focus on, is it?

No. I have recently moved to Melbourne and of course there’s no coral reefs, their water is super cold. I’m a tropical person so yeah, I really don’t like cold water. So, I moved to almost the next great big ecosystems in the coastlines, which are mangrove forests and seagrass meadows and tidal marshes.

Right. And that’s actually where we’re going to go next because you’re a project manager and research fellow at Blue Carbon Lab. Now, blue carbon, it’s a term I’ve heard before, but many, many wouldn’t have because it’s a relatively new term. What is blue carbon?

So, the term was actually coined maybe 10, 12 years ago, so it is indeed very new. And before I started working with it, I also had no idea what it was. So, blue carbon is basically a carbon that is captured and stored by marine ecosystems. And we call it blue carbon because green carbon is the one trapped by terrestrial plants that are usually green. So, it made sense to call the carbon stored by the oceans blue, just because everything in the oceans is usually associated with the blue colours. And usually whenever there’s ecosystems that are really good at storing carbon, we call them blue carbon ecosystems. So, examples of these are usually mangrove forests, seagrass meadows and tidal marshes.

Okay, so mangrove forests, I think people may have heard of, seagrass meadows as well, perhaps. We’ll dig into each of those. But what on Earth is a salt marsh?

Yeah. So basically, it looks, it’s a bit funny because it looks more like a terrestrial ecosystem. You can find in a salt marsh, plants that look like very tall grasses, like something that a cow would eat. But also, you find like suckling ones that look like something like a cacti, that would be sold in a fancy plant shop. So, there’s a wide range of species, but they all differentiate from terrestrial plants because they have very, very special adaptations to withstand the salinity coming from the tides. And they’re also really important across the world and widely recognised because they host a lot of migratory birds, so they’re a hotspot for birds and bird watchers. Like in all the coastal wetlands, you do get a lot of biodiversity, you have heaps of birds, fish, crabs and critters making it one of the most diverse places on Earth.

Let’s talk about these three areas just to get a bit of a picture in our heads about where they are. Where in Australia are we? Let’s take them one at a time. Salt marshes. Where do we find those around the country?

You find them all over the place, they’re all around Australia. They really don’t mind cold weather. So, it’s one of those coastal wetlands that really thrives also in cold weather. The other two seagrass meadows and mangroves are usually more towards the tropics, that’s where they thrive the most.

I want to quote you because you’ve just told us that we’ve got these ecosystems right around the country, but you call them ‘small but mighty’. Why are they small but mighty?

So, coastal wetlands only occupy like less than 2 per cent of the ocean’s floor, but they actually hold more than 50 per cent of all the ocean’s carbon. So, for example, coastal wetlands can store up to 40 times more carbon than any terrestrial forest. And the amazing thing is that once they capture all that carbon, they can lock it in the ground, in the soil where it belongs for centuries and millennia. So, by helping us trap carbon, sink it again, they’re helping us directly mitigate climate change.

How do they hold so much in the first place?

So, back in science class, they told you maybe about photosynthesis. So, in this case, all plants, they have the capacity to take a big breath in of carbon dioxide and they grab the carbon molecule to create their trunk, their branches, their leaves, and then they release back into the environment oxygen. So, similar to terrestrial plants, coastal wetlands can do this. But, given that they have that super funky root system and their position in that interface between land and sea, they have a wide range of characteristics in their soils that allows them to also trap a lot of carbon in the soil. In fact, like terrestrial plants capture and store most of that carbon above ground, so in their trunk and their leaves. But each time there’s a bushfire, all that carbon gets released back into the atmosphere. Also, every time like a plant dies because they last 50 years, 100 years, all the carbon gets released. But because these guys store most of it in the soil, then it gets protected from like a bunch of climatic or anthropogenic disturbances. But also, because that mud is usually waterlogged, packed with water, is very salty, it has really low levels of oxygen then there’s almost no decomposition happening, allowing that carbon that gets put in there to be sunk and captured there for centuries.

That, of course, then requires that it doesn’t get disturbed.

Yes, correct.

Which unfortunately, it often does, right? What are some of the things that threaten this amazing store of carbon?

Yes. So, there’s many things. So, I guess the main ones and the ones where most people are familiar with is like a direct disturbance by changing the land use. So, what used to be a mangrove forest is now converted into an aquaculture pond or it gets converted into an airport, airports usually are very close to the water. So, those ones, [are] the most typical ones that people know.

But there’s other, more indirect, sneaky ways in which you can disturb a wetland. So, for example, if you change the food web of the ecosystem, bad things happen all through the chain and end up disturbing the carbon stored in the bottom. So, a quick example is research shows that predators, top predators like sharks, are really important protecting carbon sinks because if sharks are gone, you get an explosion of herbivores like turtles. Everyone likes turtles but when you have hundreds of super hungry turtles munching, munching, munching all the seagrass, then that seagrass gets disturbed, and that soil gets exposed, and we release all that good carbon back into the atmosphere. So, it’s not just like directly clearing and chopping the trees, like there’s many ways in which they’re getting disturbed all around the world.

It’s not just carbon that these environments are helping us with either, right? So, you know, as a forecaster and as a, well, these days a weather presenter, you know, I’m often looking at what the ocean is doing to the coastline and we talk about coastal erosion and in a changed climate, extreme weather is something that’s happening a lot more, we’re going to see more coastal erosion as storms grow bigger and more energetic. But these environments also protect the coast from some wild weather. So, we’re not only talking about pulling down carbon, but also climate change mitigation.

Yep. Yeah, exactly. So, these are also drawing down carbon and mitigating climate change. They help us adapt. They help local communities prepare and cope to the impacts of climate change. So, as you mentioned, they help us protect the coast. So, by doing that, they help us prepare for extreme weather events and sea level rise. For example, our mangrove forests can reduce by up to 70 per cent the strength of the winds and the waves from cyclones, obviously preventing a lot of loss of lives and infrastructure. But also, we know that they enhance fisheries and biodiversities, helping us tackle the wildlife extinctions and helping local communities prepare for issues with food security.

So, for example, some research shows that up to 90 per cent of all fisheries of commercial importance depends on coastal wetlands at some point during their life stage. Another example is that in South Australia, one hectare of seagrass meadows provides around 200 kilos more fish than an area nearby that has no seagrass. So, they’re really helping us prepare for that crisis in food security.

How does that work?

Yeah, because seagrass meadows provide a lot of breeding grounds and food and habitat; protection from sharks or predators. So, there’s a lot of diversity, an abundance of fish in there. So just by having seagrass, you’re helping all those fish species be protected and you can really take advantage of that.

Obviously, these environments are ultra-important. What’s being done right now to protect them?

I would like to know; I am asking the same question. So, for example, across the world, we’ve already lost 50 per cent of all coastal wetlands. It is actually – the coastal wetlands are the most threatened ecosystem in the world. And it would be great to really protect them because that is actually the most cost-effective natural climate solution available at the moment, because by protecting them, we sort of maintain all that carbon, all that ancient carbon that has been stored there for millennia. We get climate mitigation by allowing them to keep drawing down carbon, and we get all these extra benefits that protect communities and nature against their impacts. So, their protection is actually one of the most important things we can do to fight climate change.

So, it turns out a lot of your work is in restoration. So, if we’ve stuffed it up, if we’ve lost so much, as you describe, then the way back, the less positive way back, is restoration. We’d like to preserve what’s there, right?

Yeah, that’s the main thing we need to be doing.

Don’t ruin it. But if you have, we’re going to restore it. How do you restore a mangrove ecosystem?

So, the first things to know about restoration, is that before doing anything on the side, you really need to do a bunch of homework to understand what is the main issue that caused its degradation. So, usually the first step is to stop all sources of degradation. So, for example, if its health has declined due to runoff and nutrients coming from agricultural places nearby, then you need to stop that. If it’s, for example, cattle or livestock that has been trampling all over the place, then you need to put a fence.

So, the first step is usually trying passive restoration, just stopping the degradation and allowing nature to take on and thrive. If the place has been really, really trashed then you need to get more hands-on actions. So, that would mean usually doing some hydrological works to help the tidal inundation come back and the little plants to get all the salty water they need. And if it’s too, too, too trashed, then you even have to go and manually sort of plant little baby seedlings to help it come back faster and more efficiently.

Where does Australia sit globally when it comes to not only the damage and the destruction to these ecosystems, but also our restoration and protection?

Yeah, so actually Australia is a really privileged country in terms of blue carbon. Australia at the moment holds between six to ten per cent of all the world’s blue carbon. So, we’re actually in the top three countries with the most blue carbon in the world. Australia also is a massive, powerhouse of blue carbon scientists. We have some of the top scientists in the field answering some of the top questions and then if that’s not enough, we actually have the Australian Government that is really committed to using blue carbon ecosystems to mitigate climate change. So, for example, we’re one of the only three countries in the world that keeps track and reports, under the Paris Agreement, all the captures or emissions of degrading of coastal wetlands. Also, we’re probably the only country in the world that has a national framework, a national voluntary market that allows people to restore the tidal inundation of coastal wetlands and get carbon credits for it.

Some people might not understand what a carbon credit is. What is a carbon credit?

So, in Australia, there’s what’s called like a framework, a national framework which is called Emission Reduction Fund, and this allows people to earn carbon credits whenever they do a very sustainable sort of action in their property that reduces the emissions that they’re liberating into the atmosphere or enhances the capture back into the soil. So, for example, if ‘Farmer Bob’ now gives a special food to his cows and then those cows are farting less methane, then that person would earn a carbon credit for every ton of avoided emissions. So, in this case, what we’re trying to do is restore coastal wetlands, especially the inundation and for every ton of carbon that gets trapped by those wetlands, then that person would get a carbon credit. And carbon credits are basically like a currency, it’s something you own and that you can sell in a carbon market.

So, carbon credits, is it as easy as it is on land when it comes to these ocean ecosystems? Is it as easy to quantify exactly how much carbon is – like, how do you even figure it out?

So usually the real scientific way is to get your hands dirty and get knee deep into the mud and collect a soil core. So, our soil core is, like a ‘soil sausage’. So, what we do is, we get some pipes, and we just hammer them into the mud and then we put some plugs, pull them out, and then you get like a soil sausage. Then you grab that soil sausage, slice it in the lab, run it through a fancy machine, and you literally get how much carbon is stored there in the soil. So, then the idea is that you’re going to monitor how much more carbon you have in time. So, this is the most accurate way of doing it, but it is usually really expensive and time consuming, need to get some people into the field to do all that labour. Nowadays, we’re trying to move into a more sustainable and easier way of doing it, which is using satellites and remote sensing and a bunch of fancy stuff to be able hopefully to quantify it in many other different ways.

Let’s talk about your time in the Army, the Blue Carbon Army. What is the Blue Carbon Army? Who are they? What do they do?

So, the Blue Carbon Army is a citizen science program wanting to advance blue carbon science because this topic is really important, and we really need it at the moment to fight climate change. And we do it with the help of citizen scientists, and we try to educate them on the importance of coastal wetlands and why they’re important to climate change. So, by joining us in the field and getting our full-on, hands-on experience in the mud and becoming a scientist for a day, they’re actually getting a personal connection with the ecosystem, allowing them to learn a lot, but also to change their perception on this sort of muddy, odd-looking and charismatic ecosystems that most people don’t know about. When the program was launched in 2018, thanks to funding from HSBC, we were directly targeting Australia’s top corporate executives. But now we’ve moved on and included also Traditional Owners, community groups and schoolkids.

Can you actually quantify the difference that makes? Do you know that once you’ve got someone, it’s muddy and smelly – what do mangroves smell like by the way?

Like, yeah, like life. Like salty flowers? Yes. It’s perfect.

Salty flowers. I’m on board for that. Okay, so can you actually quantify, once you’ve gotten them smelling the salty flowers and getting all muddy, if that actually changes behaviour?

Yes. So that’s one of the key things we wanted to learn from this program. So, what we did is with support from a social scientist in Cardiff University in the UK, we developed this series of surveys aiming to ask participants about their experience, about everything they’ve learned and how their perception has changed. So, we had surveys given to participants before they came and got into the mud, just after and then three months down the road. And the results were actually quite interesting.

For example, just a quick question that we asked them, we told them, ‘Tells us the three first things that come to mind once you hear the word coastal wetland.’ So, in the first go, people were saying, ‘Wet, mud, stinky, mosquitoes, dirty.’ Like all really simple terms or descriptive terms or with a quite negative connotation. But once we surveyed the people after and even three months after, they were even using words that were heaps more positive and communicated like a higher understanding of what was going on in the ecosystem. So, they use words like blue carbon, climate solution, important and fish enhancement. So, that shows here really how the program was having an impact on the knowledge that the people had, but also how it enhanced and changed their appreciation for the ecosystem.

How have you found bigger business and are they excited, do they want to get on board and help? Or has there been some resistance?

Well, with the Blue Carbon Army, we’ve always thought that it is really important to target Australia’s top industries and businesses because they’re the ones that have actually the power to invoke change and to help speed up our path to a sustainable future. So, all the decisions that they take in the boardroom have the potential to really change the course of history. So, in an era of environmental degradation and climate crisis, it is really important they have coastal wetlands in mind whenever they do any transaction or any business.

I feel that recently, industries are very motivated and really keen in this blue carbon course of conversation, mainly because there’s a lot of pressure to go into net zero emissions. So, there’s a lot of pressure for companies to offset all their emissions or to reduce them. And coastal wetlands are a perfect answer because they’re helping us bury carbon back into the ground and they’re providing a bunch of ecosystem services for people and nature. So companies, they have a lot of interest at the moment in buying carbon credits, especially blue carbon, because they’re sort of seen to have like a premium because you’re just not reducing the emissions, but you have all these extra services. So yeah, they’re really a hot, hot commodity at the moment.

There’s only so much coastline around the world, if all of these coastal ecosystems are perfectly restored and they’ve sucked down all their carbon, do we end up with a point where they’re not sucking down any more carbon, or is this a non-finishing source of carbon suction?

So first of all is, if all the ecosystems in the world were restored, we could sort of offset, I think it’s almost like 2.5 per cent, almost three per cent, of all the emissions being released at the moment in the world. So, they’re a good climate change solution. You’re not going to find any climate solution that goes 90 per cent, so this is good enough. The thing is that they do sort of saturate. So obviously, once the mangrove tree is growing, is in its teenage year, is really pumping up and growing and accumulating stuff and they do tend to flat-out a bit. But as long as they maintain healthy, they’ll keep regenerating themselves and growing and keep sucking carbon down into the soil. And the soil has a much bigger pool to store carbon.

So, that’s a big difference with terrestrial forests, like they very fastly saturate because they mainly store it in their biomass. So, once the tree grows and has, is an adult then there’s not much you can other than die. But with mangrove forests, because they store it in the soil then, you know, it’s almost endless, like there’s soil and they just keep creating soil, especially with sea level rise, because as there’s more tides coming in and the sea level’s growing, then they accumulate more sediments, more carbon, and they help us grow with the sea level rise. So, it’s almost like there’s a big, big store of carbon that we can keep growing into.

That’s incredible and very, very exciting that especially if we are just hands-off, like just stop, these places will start to regenerate. How do you work with people whose actions are directly affecting the seagrass meadows or these mangrove forests, when the actions that they’re doing that cause that damage are part of their livelihoods? What about those farmers that are, you know, that’s how they make their living?

So, it’s very tricky, I think in that stage and especially I guess farmers here, but in many countries it’s even worse because the actual local communities depend 100 per cent on those ecosystems. Like, for example, in Colombia, many communities need to take down trees because they need that wood to build their houses. So, in those environments you really try to work with the community, with the people to at least manage it sustainably. So, for example, not just target one species, try to rotate and, you know, diversify. So, it’s really all about finding a sustainable balance, because equally as important as fighting the climate crisis is making sure that the populations are well cared for.

This is obviously incredibly important to you. Could you tell me, how do you feel about where we are right now with climate change?

So, from my point of view, I think that the climate crisis is a really big challenge, and the coastal wetlands are giving us a fighting chance. They’re helping us draw down all that carbon back out of the atmosphere. They’re helping us prepare the population for the impacts. But I believe that we’re not going anywhere until we really reduce our dependance on fossil fuels and we stop releasing so much greenhouse gases in the first place. Because really, until we do that, we’re not going to have significant progress in the fight against climate change. So, these kinds of coastal wetlands are helping us, but they’re not going to solve the crisis for us.

Because I can imagine a future where – I mean essentially, what you’re offering to a landholder is, stop hurting this thing, which may be just as easy as leave it the heck alone, we will eventually be able to just look at a satellite picture and give you some carbon credits for doing nothing, potentially. That’s pretty powerful stuff, especially for, say, people in agriculture where things can be so boom and bust. This is something that could be happening on the side.

Yeah, yeah. Especially, for example, with tidal restoration, they usually have to like actually like remove bund walls or really do a bit of hydrodynamic stuff to at least allow the tides to come in. But with exclusion fencing is literally as simple as putting a fence and preventing livestock from going in there. So, it’s a very low cost, sustainable methodology, an action that many people can do, and they would be protecting the ecosystem, allowing it to keep trapping carbon and preventing from all those blue carbon bombs to come back into the atmosphere.

Thank you so much. Please, say thank you. Maria, thank you for the chat. To follow the program online, you can subscribe wherever you get your podcasts. You can also visit the 100 Climate Conversations exhibition or join us for a live recording like this one. You can go to 100climateconversations.com and just search for 100 Climate Conversations in your pod catcher of choice.

This is a significant new project for the museum and the records of these conversations will form a new climate change archive preserved for future generations in the Powerhouse collection of over 500,000 objects that tell the stories of our time. It is particularly important to First Nations peoples to preserve conversations like this, building on the oral histories and traditions of passing down our knowledges, sciences and innovations which we know allowed our Countries to thrive for tens of thousands of years.