Welcome to In-Orbit, the fortnightly podcast exploring how technology from space is empowering a better world.
[00:00:00] Dallas Campbell: Hello and welcome to Outer Orbit. In these little shorts bonus episodes, we're going to be continuing the conversation from our main episode, focusing in on a particular topic or an idea or a particular point of view. Anyway, in today's episode, we are joined by Sean McCarthy to explore blue carbon. Ever heard of blue carbon? Well, what is it? Why is it important to the climate change conversation? And what could it mean for our future? I always like it when these chats kind of go slightly off topic and this is one of them. It's not really off topic. I mean, we're talking about sustainability really, and you started talking about this idea of blue carbon. So tell us what blue carbon is.
[00:00:49] Sean McCarthy: The reason I think it's interesting is that it's... we're talking about storing carbon, all to do with climate change and sequestration of carbon. So storing carbon naturally and that's in the coastal environment. So you're talking about mangroves, seagrass and salt marshes.
[00:01:08] Dallas Campbell: Before we get there, when you say storing carbon. So this is this idea of, it's not just enough to cut down our carbon usage, we actually need to pull carbon out of the atmosphere in order to reduce it.
[00:01:23] Sean McCarthy: So if you think of how a mangrove, plant grows or seagrass grows, it photosynthesises and it draws in carbon from the atmosphere to build its cells and then the interesting part about carbon sequestration in sea plants is that it goes into the, you know, the substrata into the soil and it remains there and it's not going to be used by farmers or something like that, it will just remain there.
[00:01:56] Dallas Campbell: So, okay, then explain the benefits of that rather than just planting trees or...
[00:02:03] Sean McCarthy: Well, one of the issues with planting crops or trees, or certainly the issue with planting trees, is that you're using land that could be used for producing food, or building on, or...
[00:02:14] Dallas Campbell: We like trees.
[00:02:15] Sean McCarthy: We like trees, but what's also interesting about the blue carbon concept of encouraging and restoring mangroves, or seagrass, or salt marshes, is that over not just the last few years, but over thousands of years, these have been removed and they've been damaged in the past. We're not quite sure what the baseline is for a healthy planet with regard to blue carbon, with regard to these big areas of seagrass.
[00:02:46] Dallas Campbell: Does the blue bit just refer to the sea?
[00:02:47] Sean McCarthy: This is just the sea. Yes, yeah, this is wet carbon in the sea and in fact, you could extend it to fresh water as well. but this is predominantly, looking at coastal areas and these seagrass meadows are huge, acres and acres of them and a seagrass meadow, depending on who you're talking to, sequesters four times more carbon than a tropical rainforest and...
[00:03:17] Dallas Campbell: Why? How, what's the mechanism that makes it such a good absorber of carbon?
[00:03:22] Sean McCarthy: So, most of the carbon in a tropical rainforest is in the bit above the ground, whereas in seagrass, most of it's not in the grass itself, but in the root structure, which can extend for hundreds and hundreds of acres and that just builds up more and more. So, what tends to happen is a bit like a sand dune on a beach or a, you know, looking at the grass on the beach that it builds up and it traps sediment around it and then it builds on top of that so it keeps on increasing in height and these seagrass areas can be six meters deep of pure seagrass root, whereas you don't get that on the terrestrial side. Most roots don't go down below, much below a foot or so.
[00:04:08] Dallas Campbell: And so the benefit of that is it doesn't get disturbed. It's not...
[00:04:11] Sean McCarthy: It doesn't get disturbed.
[00:04:12] Dallas Campbell: So I mean, once the carbon's there, is it there for as long as the plant lives? How far, what's the...
[00:04:21] Sean McCarthy: Millennia. It's there for thousands of years and eventually, presumably, I'm not quite sure of this, but, you know, it will be compressed and then it will be what may have made coal or what may have made, oil or something like that, you know.
[00:04:35] Dallas Campbell: We can burn it.
[00:04:36] Sean McCarthy: We can come back and burn it up eventually!
[00:04:38] Dallas Campbell: We'll have another industrial revolution in...
[00:04:40] Sean McCarthy: Yeah, we'll clear up first and then we'll start again. But, actually that starting again, concept I think is quite useful in this context. That's the blue carbon is the concept of restoring, for example, mangrove is something that's relatively new. It's only been sort of looked at in the last decade or so.
[00:05:00] Dallas Campbell: Yeah, just give me a little bit of history, please. People have been talking, I mean, I've heard about algae farms as a sort of geoengineering idea, a way of sequestering carbon out of the atmosphere, which never really took off and they're always very controversial, these schemes you hear about.
[00:05:14] Sean McCarthy: You say it didn't take off. But actually it's a very big growing activity now.
[00:05:19] Dallas Campbell: Oh, really?
[00:05:20] Sean McCarthy: And it didn't take off initially, because there's very small scale pilot studies and nobody could make money out of it, so these things didn't happen and this is the challenge for blue carbon is how do you make it a reliable, I don't know, offset, if that's what you want to do, you know, I'm not keen on offsets generally but, you know, if there's a way of making money out of it, or there's a way of getting investors to put money into it, that'd be good. But what I was going to say is that the, you know, because it's a relatively new area, it shouldn't, or at least we've got to be cautious that it doesn't suffer from the same problem as greenwash for terrestrial projects and programs that, you know, the evidence for their benefit isn't that great. You can actually see the benefits in doing blue carbon projects because you get more fish, you get more jobs for... biodiversity is massively increased there. It's a little bit, coral isn't considered a blue carbon project, if you like, but it's a similar sort of thing, once you get something there, a habitat growing, mangrove for example is the, nurseries for fish growth that would encourage fisheries and jobs in relatively often poor areas as well, so it's got a big social impact as well.
[00:06:45] Dallas Campbell: Just, can you tell us just briefly about the financial incentives? Like, is there some kind of model that would make this attractive that would get sort of financial backing? Cause that seems to be where everything falls apart. It's like, well, there's no...
[00:06:59] Sean McCarthy: That is the challenge that clearly if you, had a proper functioning carbon market then you can very easily work out what the, well you've not maybe easily, but you can work out what the sequestration over an acre of sea grass is, for example and then you can get people to invest in carbon in that case. But the challenges and the things that we'll be looking at are, you know, how do you measure that? And that's where the satellites come in.
[00:07:27] Dallas Campbell: When you say you'll be looking at, are you...
[00:07:29] Sean McCarthy: No, the industry will be looking at...
[00:07:32] Dallas Campbell: But is this, are the industry looking at it at the moment or is this still...
[00:07:35] Sean McCarthy: It's mainly academic and mainly academic, but there are some charitable trusts and things like this looking at it. But, the UK. It's particularly good at this, we're an island, we've got a lot of universities that have...
[00:07:47] Dallas Campbell: Not much mangrove in the UK
[00:07:48] Sean McCarthy: ...we've got a lot of seagrass though and we've got a lot of salt marsh and they're, you know, mangrove gets in the press because you can see it and you know, you can sort of, look at the mangrove swamps in the Far East or whatever it is, but, you have mangroves I think in South America as well, but, the seagrass is just as efficient at absorbing and sequestering carbon. So we should encourage that here. Oh and by the way, it's being, around here, it's being damaged by some of the, practices of the fisheries. So it's bottom trawling and collecting, you know, shellfish or whatever it is off the bottom has been going on for hundreds of years and has been destroying these areas for hundreds of years. So that's where we need the regulation to come in and then encourage the seagrass to grow. But you actually have to plant it out, so it's quite tricky.
[00:08:45] Dallas Campbell: I love stories like this. Where can we direct our listeners? Where would you recommend they, if they want to find a bit more about seagrass sequestration, carbon sequestration?
[00:08:53] Sean McCarthy: One of the easiest things to do is to go onto YouTube and just type in blue carbon, and there are a lot of organisations, both in the UK, in the States, in the Far East, Australia. If this is sorted out properly, it will be sequestering more carbon than forests. So you can see that it would be really beneficial to actually...
[00:09:15] Dallas Campbell: Absolutely. I'm going to get onto YouTube and look at this. I love little nuggets like... listen, thanks for coming in and sharing that.
[00:09:22] Sean McCarthy: And it's, something that I think the big industries could get behind, banks could get behind it.
[00:09:27] Dallas Campbell: Yeah and ultimately all the stuff that we've been talking about in terms of satellite comes down to sustainability and the environment anyway. So here we are, another little offshoot of that.
[00:09:38] Sean McCarthy: By the way, these places are difficult to get to, generally, which salt marshes and yeah, mangroves and things. So you do need a, you need satellites and you need little robots to go out and plant the things and those can be controlled by space as well.
[00:09:53] Dallas Campbell: I love this!
[00:09:53] Sean McCarthy: It all links up!
[00:09:55] Dallas Campbell: Yes, where's Arthur C. Clarke when you...
[00:09:57] Sean McCarthy: When you need him!
[00:09:58] Dallas Campbell: To hear future episodes, be sure to subscribe on your favourite podcast app, and to find out a bit more about how space is empowering industries between episodes, why not visit the Catapult website, or join them, or me, on social media.