The Blindboy Podcast - Speaking with a professor about the evolution of plants, terraforming planets and extinction events

Episode Date: November 5, 2025

Professor Jennifer Mc Elwain joined me for a chat about Paleobotany ahead of Science week 2025  Hosted on Acast. See acast.com/privacy for more information.

Wish upon a pinprick, you whispering Vincent's, welcome to the Blind Boy Podcast. If this is your first episode, consider going back to an earlier podcast. To familiarize yourself with the lore of this podcast, I'm looking out over a navy, limerick city from my office window. It's only half four and things are getting dark. Fairly soon there'll be a carton of bastard rain, which is a... dense mist. A dense freezing mist. There's very little sunlight. Even in the daytime. Everything's purple. And sunsets aren't powerful anymore. They're kind of pink. Because in November the art is tilting at a quare angle. So the sun, the sun has to pass through more atmosphere

and it just scatters more blue wavelengths so that's why the sky is not even the sky, the general vibe is purple and blue and there's very little bard sounds, you're not hearing the sounds of birds chirping anymore, the starlings are gone they're going off for their winter roast

and everything is about decay the leaves are on the ground the trees are all spindly and silhouetti and there's an icy chill coming in we'll have that in a couple of weeks And just a few days back it was Halloween, which comes from the much earlier Irish seasonal celebration known as Sowan. And we can see this written down in the 11th century and the 10th century, but the story

goes is that there's a cave up in Ross Common called Onigat Cave. And this is the Helmoth. It's a portal to the other world. The veil between our world and the other world is very thin. and horrible monsters and demons or whatever you want to call them escape from this cave and they maraud the land and strip it bare that night and then the next morning everyone wakes up and everything's gone there's no leaves things are laid bare by frost

there's no insects there's no animals and that's really what halloween is it's a big story about winter in the absence of writing It's a story about ecology, about biodiversity, and I love that it still rings true. I love that I can look out on the 4th November and see the land stripped bare by winter. Because as dark as it is, as ugly as it is, as unpleasant as it is, it's what's supposed to happen. It's necessary. And I love the challenge every single year to find meaning in all that darkness.

because this is a tough time of year. It's a tough time a year for our mental health. A lot of people, myself included, don't respond well to that lack of sunlight. To the ugliness, to the ugliness that's out there. November is not aesthetically beautiful. We have to really search for that aesthetic beauty. If you get a bit of snow and frost and it twinkles,

fair enough, that's aesthetically beautiful. But I'm looking out at underpants right here, lads. the shrivelled up testicles of God that's what November is but I have a choice in that I could allow myself to be depressed by how bleak everything is or I could see it as a challenge

a challenge to find meaning and beauty in it and that's what I do every single year and there's loads of meaning and beauty in winter and one of the best ways to access that beauty it's true science it's true understanding what winter is it's through understanding

ecosystems and biodiversity. This week's podcast is it's my annual Science Week podcast which I've done, I think every year of this podcast I've done a Science Week podcast in November. And every Science Week I get to speak to an expert in their field

about an area that they're very passionate about and it's a wonderful privilege and that's why I love doing Science Week. but this year's Science Week 2025, it's running from the 9th to the 16th of November it's the 30 year anniversary of Science Week

so Science Week has been going for 30 years and there's just, there's loads of free events up and down Ireland, right? In libraries, colleges, schools for everyone. It's about accessibility and democratising science.

It's not just for little kids who might become scientists. But it's for adults like me who are just curious, curious people who want to learn and find out about the world around them through the language of science. So wherever you are in Ireland, I guarantee you that it's going to be a Science Week event near you. It'll be free, it'll be fascinating. And if you're struggling with November,

it will give quite a lot of meaning to November. There's an entire week in November where there's free science events for you to go to and engage with while we all wait for things to get a little bit Christmassy let's be honest all right

we're all waiting for things to get a small bit Christmasy we want Christmas lights and Christmas songs that artificial injection of merriment that we need at the end of November

and December because it's bleak but right now we've got nothing because Halloween just happened and we're waiting for the Christmas stuff so you've got Science Week okay you've got Science Week right now So that's starting on the 9th.

And my Science Week guest this year is Professor Jennifer Mechlewain from Trinity College up in Dublin. And Jennifer is a paleobotanist. She's a world-renowned expert in paleobotany. She's published a book called The Evolution of Plants. She's been involved in incredibly important research on plant evolution and also how plants have changed our atmosphere over the years and have terraformed Earth and the theme of this year's Science Week because it's the 30th anniversary is then today and tomorrow and paleobotany is perfect

for that theme because it shows how plants change the planet in the past how they record atmospheric change today and how they can guide climate action for the future so myself from Jenny chatted about paleobotany, ecology, biodiversity. We had a wonderful, wonderful chat. And most importantly, and I tried to do this every single science week, I'm speaking to an expert, a professor, someone who has dedicated their life to research in paleobotany, and I just have to be mindful around that, that, because I didn't have a great time in school, I have to be mindful around it that to approach this situation with playfulness and curiosity and to ask the silly questions. To ask the silly questions.

The stuff that I got killed for in school, asking too many silly questions. Well, now I'm an adult and silly questions have value. There's no such thing as a silly question. I think what's silly is not asking the question you'd like to ask because you're scared of looking stupid. That's what silly is. That's silliness. There's no such thing as silly questions.

So anyway, here is the wonderful chat that I had with the incredibly sound Professor Jenny Mechlewain. So paleobotany is the study of fossil plants and we have different pediobotanists. Some people kind of look at shallow time over the last just a few million years. I study what I call deep time. And so I look at study fossil plants all the way back to about 450 million years ago.

So one thing I'm very curious about, right, is mass extinction events. And there's something I'd love to run by you because I need to know if it's just some bullshit I heard on the internet, right? I was looking at, so I heard that all the coal that we're burning today, all this cold that's caused so much damage to the environment and release. much carbon that this coal started during a giant extinction event of trees like 390 million years ago and that's these trees couldn't decompose because fungus didn't exist that could decompose them. Is that a thing that happened? Yeah, it is absolutely. So, yeah, we know that there were at least five of these events called mass extinction events, and it's when an extraordinary number of the species on Earth go extinct,

and we try and understand what happened. But the one you're talking about happened at the end of the Devonian, and this was a time, if you can imagine, Ireland was actually in the southern hemisphere, and we had some of the oldest fossils on Earth, and today you can find them near Kilkenny, in Kilthorcan. They were called Archaeopterous Hybernica. And, yeah, basically that the extinction of those trees brought in these new forests, which were called the coal forests or the coal swamp forests of the Carboniferous.

And for basically, 50, 60, 70 million years, these forests grew. The big, huge trunks fell down into the swamps because it was really tropical, wet, swampy. and there's a hypothesis or this theory that the fungi weren't around to decompose those giant big trees made up of lignin so what happens over time is that slowly instead of being oxidized back to the atmosphere and the carbon that was taken up goes back to the atmosphere

and these giant peat swamps grew and grew and grew locking up huge amounts of carbon and what we've done as humans is that we've burned that carbon that took 50 million years to take up and we've done it in 100 years so we've caused this kind of this this imbalance which is the kind of fundamental reason we have climate change now i've i've described that before as we're haunting ourselves with the ghosts of trees that that's it's it's this stuff was supposed to stay down there and we've brought it back up as coal

and just another kind of general simple question about paleobotany we know the word paleontologists from Jurassic Park and stuff and and friends and friends of course as well like would you ever

like I know that dinosaur poo right is copper light fossilised poo would you ever end up looking at a fossilised dinosaur poo because there might be a bit of a leaf in it. Oh, God, yeah. Is that like that's when your job comes in? Yeah, but I hope it's more glamorous than just poo.

Yes. Yeah, actually, I give you a great example. So grass, so if you think of our lawns all over the world, the great grass savannas of Africa, the great grass steps of Siberia. That plant is actually, the whole family is very recent. and the first find of grass in the fossil record was about 65 million years ago

it was in a dinosaur poo before dinosaurs went extinct at the Cretaceous tertiary mass extinction like bones take you know bones are going to take a bit longer to decompose yeah a leaf a leaf will decompose in a matter of weeks

so your field you're trying to look for the fossils of things that are supposed to to decompose and disappear really, really easily. Like, how does something like a leaf even end up being... A fossil? Yeah, like, what's going on here? Yeah, yeah, it's a really good point.

So I suppose, yeah, and we realize that at the moment, like walking through awesome leaves, there's nothing nicer, you know, putting the wetties on and going through the leaves. But literally in a month, where are they, they're gone? They're decomposed. So to be a fossil, to become a fossil, a plant has to drop one of its parts a flower, a leaf, a twig, a trunk and it has to be covered really quickly by something that will stop it from decomposing

and in the natural environment what that would be would be a river bursts its bank and it puts sediment over everything in the forest floor so you're basically just capturing that moment in time or a volcano will go off and ash will cover all the leaves on the forest floor on the forest floor so something that would cover it

and take it out of so actually being eaten and ending up in a coprodite a dinosaur poo or that would also stop it from being decomposed so any of those kind of events and then as a paleobotanist I will

kind of work in the field we'll use a hammer and a spatch and a chisel and if there is a fossil leaf there when you crack it with the hammer it's like opening a book and the fossil appears because it makes a line of weakness

in the sediment and you just crack it open and the fossil is there and just so let's just say we take a big giant lump of coal now that coal that's a fossil of sorts right? We know that that coal was once a tree

but I suppose what I'm asking you is I don't, coal isn't a very well preserved tree, is it? Like is a lump of coal still useful to you as a paleobotanist? Yeah, well kind of. It's kind of difficult. So, okay, the coal is black but in the coal now and again you get these things called concretions and they're like a big light grey egg and the coal miners used to go mad at these sinks

because they'd ruined the coal production. You'd have to stop. And what it is, it's like a mummified forest floor. And it's been formed because the coal, which was a peat swamp. You imagine a forest in a peat, just like in the Midlands and Ireland, and a wave of seawater will wash into the swamp because it's right by the coast. So now you've got salt, you know, you've got sodium,

chlorine and the salt elements, they interact with the swamp waters and they form these kind of mummified floors full of twigs and leaves and cones and anything, insects, anything that was on the forest floor. So we can actually study those, they're called concretions or cobales and we can get a really incredible picture of what was growing, what the environment was like. We can even use it to reconstruct what the climate was like and what the atmosphere was like. But the coal itself, the black coal itself, is actually hard to work with. And the only things we could really look at in fossils are tiny little fragments of leaves or the pollen and the spores that plants produce.

I'd said this to you before, right? But I know some of your work was about how Earth was terraformed effectively by plants, okay? And last year when we had the Aurora Borealis in Ireland, and I could see the Aurora Borealis up in the sky in Limerick for the first time in my life I went out for a walk and it was night time and I was looking up in the air going

oh my God it's Aurora Borealis I can't believe it but as I was walking I went past this old shopping centre it was a Celtic Tiger shopping centre that hadn't, it had been left alone since 2007 and as I was looking up at the sky illuminated by the streetlights a stark flew past me

but the stark I was like, that Stark looked like it had green socks on or green shoes. And I went, no, no fucking way. Like, that's not possible. That's not, like, I saw, I know, I definitely saw what I saw. But like, there has to be a rational explanation. A Stark was not wearing boots or socks. So I ended up going on Google Maps and looking at this particular Celtic Tiger shopping center.

And what I found was where the foundations were, over the course of about 15 years, there was a rainwater lake. had just formed. Very, very unhealthy lake. It's in a concrete foundations and it was bright green. So what had happened is the stork had gone into this green Celtic tiger

foundation lake and on its legs was actually cyanobacteria. And I only learned about cyanobacteria in that moment. Like I was really happy because I'm like, I can't believe I'm actually after finding

an irrational explanation for a stork with green socks. But then I ended up down the cyanobacteria. a rabbit hole. First off, I was disappointed because chances are it's not very healthy for the stork. It's quite poisonous to the stork. But then I learned that cyanobacteria is one of the most important organisms in the history of life as we know it. And this bacteria, I don't know how many million years ago you'd know, created oxygen. Can you tell us about that about the great

oxygenation event? Yeah. It is incredible. As soon as he started talking, about, yeah, the cyanobacteria-filled lake. Yeah, it made me think about, just imagine the earth when there's nothing green on it. So just a bare earth with no soil, no plants, no algae, nothing green. No, and this was earth before complex life evolved on land. Was there what you'd call life even before this greenness? Was there stuff there that was alive?

Yeah, so there was microorganisms. We have billions of years of just bacteria and new bacteria and just very simple organisms, but they're not multicellular like we are or like most organisms on Earth. But the cyanobacteria were so important. They're actually some of our first evidence for that life had evolved. And they appear in these structures, which are like, these sediment towers and they're called stromatolites.

Today you find them in very rarely on earth in places like Shark Bay in Australia. And what the cyanobacteria do is they trap sediment in a kind of a nice shore, like seashore type environment, whether it's a muddy shore, kind of like Dublin Bay. And they would, they'd form a layer of green slime, like the green slime of the stork's boots. And then a layer of sediment would build on top. layer of green slime and they basically build these towers. And the reason paleobotanists are really interested in them is that they're the first evidence on earth of photosynthesis.

And these little cyanobacteria would take in carbon from the atmosphere, use the sun's energy, convert it into carbohydrates and build these whole little communities. But the byproduct is oxygen. and over a long geological time, oxygen went from basically zero percent, so we would have all died in that atmosphere, to suddenly you start to get trace levels of oxygen. And this production of oxygen in itself caused an extinction event of all the organisms that were anaerobic.

They basically couldn't survive with oxygen around. But it was so important for where we are today in this world, full of life, animals, plants, fungi, because we need oxygen for survival. So is it fair to call that terraforming? When the cyanobacteria created a photosynthesis and oxygen, is that terraforming? I think it is because my definition,

well, like, not mine, but I would say the definition of terraform would be transformation of the earth. And of course it's used in science fiction. but yeah because i'm just thinking of mars that's what i'm thinking about is is like even i think it was over the summer NASA now i know i know NASA always released this type of information but NASA found stains on a rock in on mars which they say may suggest ancient bacteria that's what it might suggest they're very excited about these stains on a rock on Mars

and is there this is a really ignorant question but I have to ask it right and I hate asking this question about anything and I probably won't be able to answer but let's see your thing is looking into deep time

millions and millions of years into the past right and some people would say what's the point how is it relevant now and one practical application I can think of is if you're studying how Earth was terraformed A lot of people are thinking, what if one day we need to go to Mars

and try and make oxygen happen in Mars? And that makes me think that the work that you're doing is highly relevant when it comes to trying to apply that now. No, no, I don't think so. So, well, I kind of think there's two answers. I think science is important to understand the world without any application. Like, I do fundamentally believe that,

that I just want to understand. the past. I want to know how I got here, how the world ended up like this. So I think that the kind of pursuit of truth and understanding I think is really important. But then there's the other side, the applied side. And actually a lot of a lot of paleobotanists have been on these various Mars teams, moon teams, exploration of other planet teams, because the kind of science we use, it's not my area, but the science we use to try and prove, or was that little dot life or was that a bubble, which is abiogenic, so it's not biotic. We'd use things like chemistry, carbon isotopes, and the kind of tools you use to understand the fossil plants

would be the same tools that a Martian scientist would use to understand, okay, was that water, was that sediment evidence of running water, or was that structure or that smear, was that really potentially a bacteria or something else? So in that way, there is a crossover between astrobiology and paleobotony. But they're typically, the paleobotinist you study, these type of things are really they really are deep time so they'd be

working between you know 2.4 billion years ago the great oxygenation event and maybe the evidence of the first land plants about 550 million years ago and my kind of science comes in after that so I'm kind of shallow in a way 550 million years to the present day

that's what I want to know yeah because we're thinking about this like deep time when where is your jurisdiction at what point to you. I mean, and again, it's the wider question, and I ask this to every single scientist I speak to, is the sense of knowing where your lane is and how difficult that is when you're working effectively within biodiversity. You're looking at ancient plants, but we know that ancient plants had a relationship with the atmosphere, with the sun, had a relationship with animals, and you knowing when to stop. Oh, yeah, that's a good question. how do you know when to stop?

I mean, how do you put a shatter on your curiosity going, I'm looking at a flower here that's millions of years ago and I want to know about what pollinated this before bees existed. Yeah. Gosh, that's a really good question actually. And I think in a way, scientists, we are very lucky because we do have freedom in our careers to decide where to put the barriers.

You know, so we have freedom. to define what we want to do and what questions we want to ask. Now, obviously, you have to be able to fund your work with, you know, funding agents and grants. But I suppose the questions we ask are very much determined by our passion and our curiosity. And then, but we have to make it relevant as well

because we can't, you know, so there's kind of two sides to science. there's that basic fundamental science where you're just letting your curiosity drive you. But then you do, if you're using public money, you also have to make it relevant. So we kind of, a scientist, we kind of balance that. I don't think you could make a, deliver a public good

or something of relevance and something applied unless you had that kind of innate curiosity that's driving you to ask these kind of crazy questions. like what was happening 400 million years ago and if I understand something about how soil was made in the earlier, will it help me to say anything about the future or today? Okay, let's have a little pause now. A little ocarina pause in the chat

with the magnificent Professor Jenny McElwain. I don't have an ocarina this week. Let's not get into that, but what I do have. instead of playing an ocarina I'm going to hit myself into the head with a book The Collected Poems of Patrick Kavana who was

a magnificent poet from Manahan Brilliant book about about Kavana There's a brilliant biography about Kavana Brendan Behan and Flan O'Brien and their drinking days up in Dublin It's called

Dead as Dorness by Anthony Cronin Wonderful book But Kavana was a serious poet I don't want to get too much into Patrick Cabinac because I won't stop talking about him I'll do a Patrick Cavana podcast at some point But right now

Let's just read a little bit Do you know what? No I'm going to hit myself into the head with his book And then you're going to hear some adverts for some bullshit I don't know what you're going to hear an advert for I'm going to hit myself into the head with Patrick having his collected poems and then afterwards I might read a little bit

of one of his poems. How does that sound? All right. Oh, ho. See, it's one of these fucking new penguin classics where they don't even bother putting a decent cover on it. So, very papery, very rubbery. A very flaccid book.

And you'd think hitting yourself into the head with the floppy books that's far worse than hitting yourself into the head with a hard book. I'd take a hard book any day. Flappy books. See, they pick up speed. It's the spring. Oh!

All right. That was the ocarina pause. I hit myself into the head with the collected poems of Patrick Kavana. You'd heard some adverts for some stuff. Let's read a little bit of Kavanaugh. his poem Stony Grey Soyl From the 1940s

When is that poem from That's from the 40s I believe yeah I'll read you a little excerpt Stony Gray Sile You told me the plough was immortal Oh green life-conquering plough Your mandrel stained

Your colter blunted In the smooth lee field of my brow you sang on steaming dunghills A song of cowards brood You perfumed my clothes With weasel itch You fed me on swinish food You flung a ditch on my vision

Of beauty Love and truth O stony grey sile Of managhan You burgled my bank of youth And I love that poem It's just It's just Kavana

Cavana walked I don't want to get into Patrick Cavana too much He was a bogger poet He was a poet from fucking Monaghan In the 30s and 40s And he walked to Dublin barefoot And the kind of middle-class posh people in Dublin They treated him like a noble savage

Like he wasn't even human He was this bog creature And that poem is him Him going to Dublin And seeing like a city And like multiple pubs and pints And women and having crack And going fucking Monaghan

I stayed in you too long Why didn't I come to Dublin ten years earlier I don't want to be getting into Paddy Kavana There's a brand statue with him up in the I think it's the Grand Canal Up in Dublin It's this lovely statue because it's just it's a bench. It's a bench and sitting

on this bench is this green bronze statue and that's the statue of Paddy Kavana and when I was a young man when I was about 23 and I'd be writing skits for fucking RTE and

didn't think I was good enough couldn't believe I was on television writing comedy, couldn't believe it I used to go and sit beside that statue of cabinet and when no one was looking I'd suck his bronze hat I'd try and suck inspiration out of his bronze forehead and it tasted like sucking a giant kind I loved it support for this podcast comes from you the listener via the Patreon page patreon. patreon.com forward slash the blind by podcast if you enjoy this podcast if this podcast brings you mirth merriment entertainment

distraction, whatever the fuck has you listening to this podcast. Please consider paying me for the work that I do. This podcast is my full-time job. This is how I earn a living. And this podcast is only possible because of listener funding. So all I'm looking for is the price of a pint or a cup of coffee once a month. That's it. And if you can't afford that, if you don't have that money, don't worry about it.

You don't have to pay. You can listen for free because the person who is paying is paying for you. you to listen for free. So everybody gets the exact same podcast and I get to earn a living. It's a wonderful model based on kindness and soundness. Patreon.com forward slash the blind by podcast. And if you are becoming a patron first off, become a paid patron. Don't press that free patron button that just gives Patreon your data. And also, if you're signing up, don't do it on the iPhone app because Apple will take 30%. Do it on a browser. somewhere. I write a couple of gigs. I just did my last gig of the year there at the weekend

Halloween night in Mead. Really wonderful gig. Mead is a beautiful place. So I've no more gigs this year. I don't want to be doing live podcasts in November and December and the main reason is because of Christmas parties. Office Christmas parties, if they come along to a live podcast, can be really, really destructive I've had it once or twice so the best thing for me to do I just don't gig in November or December but I will be gigging from

the end of January 26 onwards so if you'd like to get some tickets as a little Christmas present for a friend please do on the 23rd of January I'm in Waterford in the Theatre Royal Wonderful Waterford

then up to February what is that the 2nd of February I don't know the exact day right but it's in February I'm in Vickers Street I'm in Vickers Street Is that a Wednesday night fucking great

Wednesday night gig in Vickr Street there at the start of February That gig there is nearly sold out I have to say so if you do want to come to Vicker Street my Vickr Street gigs are fantastic Beautiful lovely I always do them midweek I do them on the days that no one else wants I take Tuesdays and Wednesdays

No one else wants those days I want those days because it's a nice quiet gig Then on the 12th I've got Belfast at the Waterfront Theatre That gig is also nearly sold out So if you want to come and see me in Belfast at the Waterfront Theatre Get your tickets Galway in glamorous glamorous Leisureland

Let's go 15th there is Galway in Leisureland Then Calarnie I'm in the Aineck on the 28th of February I have a complicated relationship with the Ainec I keep coming back What's my complicated relationship with with the Aineck. Lovely place, lovely venue, lovely staff, but the dressing room. So that gig in

the in Ainek in Killarney, the dressing room is just too far away from the stage and it would mean me having to walk through the foyer of the hotel that's attached to the venue with a plastic bag on my head and I don't do that in case there's tourists in the foyer who don't know who the fuck I am and they're just, they just think I'm in Isis. They're like, oh I'm in the hotel of there are a man here and he's got a plastic bag in his head, this is strange. I've had screaming Austrians. I've had Austrian people scream at me

in Hotel Foyez while I'm on the way to my gig in the hotel. So the eye neck, yeah, the eye neck there in Killarney's got a hotel attached to it and the dressing room it means me walking through the foyer so I say no I'm not taking that dressing

room. So I end up in a literal broom closet. Like a Dracula, like a vampire. When I do that in a Kalarni gig, I stand in a broom closet for an hour with the door closed and that's my dressing room, which I don't mind to be honest, I quite like it, I like the humility of it. But yeah, I'd rather stand upright in a broom closet for an hour than risk Austrian tourists

screaming at me because they think I'm in Isis. So that gig is the Inek in Calarney, is it? Then I'm in Carlo in March. Did I just finding that out now? Should we go to Carlo? Why not? What's the worst it can happen? Cork in March as well in the Opera House there on the 26th of March. Fuck sake.

Limerick in April at the University Concert Hall, Limerick. Get your Christmas tickets for that, please, Limerick. my own hometown and then fuck it look a huge tour of England, Scotland and Wales in October 26th. It's a long way away but still some of those gigs are actually selling out

already and it's a year away Brighton Wales Coventry Bristol Guildford London Glasgow Gateshead and Nottingham 2026 October I'm coming

and I cannot wait those gigs you'll see I'm on Fane.co. UK forward slash blindbuy for the UK gigs and then for the other gigs. The Blindby Podcast.orgiae which is my own website

which is liable to crash if too many people go there. I'll be honest. All right. Now let's get back to the chat about paleobotany with the utterly fascinating Professor Jennifer McElwain. Does that answer it? I'm not sure I answered it. It does. I'm trying to figure out

we'll say what the questions I'm trying to ask is like soil, even soil for instance. So soil isn't a plant, right? But how much of soil is your business? Ancient soil. Yeah. So I suppose my, my speciality is the atmosphere. So how plants. But the atmosphere isn't plants.

Exactly. So, yeah. So I, if we want to understand the power of living plants mainly to change atmospheric composition, to change oxygen, to change carbon, to actually come up with some solutions for greenhouse-driven climate change. You have to understand how plants terraform, how they change the atmosphere and the habitability of the earth in the geological past.

So we know from studying from the time of the first land plants came on Earth, There was no soil, it was bare rock, but little things like mosses and liverworts and green slime and lichen and all these mad organisms that kind of are half fungi, half plants, half algae. They began to break down the bare rock and build an early crust. Wow. And then that crust became a shallow soil. And then that shallow soil became a deep soil. And now suddenly you've got a whole new habitat. that. Like just if you're talking about that early, early, because that's, I didn't know that. I didn't know that early soil was organisms breaking down rock. So if I was to hold this early soil in my hand, what would be the equivalent that I'd find now? Because I'm assuming it's not like brown like the earth we have now. I think the equivalent, to kind of get your head in the frame, I think would be look at a wall today. So go on a walk, look in an old wall, a nice old granite wall.

and look what's growing on it. How do those plants green... Or gravestones. Or gravestones, exactly. How do they do it? How are they living? Okay, they've got carbon in the atmosphere. They've got sunlight, energy.

But they need all these other things to live, and they're just extracting it directly from the rock. So are you telling me, if I look at a gravestone and I see lichen on that gravestone, that the roots of that are taken from the limestone or what granite or whatever it's on? yes but it doesn't have roots so it's doing it even more spectacular another good analogy would be a desert environment so that's really harsh not many things can live there but often if you go hiking in a desert environment they have signs up saying you know stay on the trails and if i'm thinking why what's the i'm not going to do any damage if i come off the trail but you will because if you dropped a little drop of water onto a desert crust and what looks kind of browny, yellowy, suddenly would rehydrate and you'd

see a diversity of organisms that can basically eke out in existence and there are things that would have been around in the earlier 500 million years ago and kind of changed made elements

that we need to grow and we need in our diets nutrients basically they'd make them biologically available. Are they dormant in the desert? Yeah, yeah. For how long? Well, some things are incredible.

Some plants, they're called, it's called poikilohydris. So they have the capacity to completely dehydrate down to less than 5% water. And how do they do that? Because if you put a piece of lettuce in the freezer, it will, and you rehydrate it. It's just mush. But these organisms have the capacity to dehydrate and then rehydrate without bursting all their cells. And they can do it for. I think probably the oldest is maybe on the order of maybe thousands of years,

but most things can do it for hundreds of years. Even if you go to the Burren, actually, in County Clare, and you look at the ferns in the grikes, there's, you know, the kind of cracks. Sometimes you look at them and they're brown and they're not dead. They're just dehydrated. And when it rains, they will rehydrate and they've got this capacity. And that's really interesting. That kind of takes you back to space travel.

That's immediately what I was thinking about. I was thinking about if we were to bring food in space and you might be travelling for a long time, then you'd need to be looking at these things that can live for 900 years dehydrated. Exactly, yeah. Well, I think what's incredible, I mean, I talk to my students about this, you know, and teaching.

If you walk into a garden centre and you're faced with a wall of packets of seeds, that is incredible because in every packet is a, a dehydrated living organism with all the potential once you put it even if you put it in a on a saucer

and add water or on a place it will germinate now there's not we don't have equipment in animals you know you don't have you can't go into a shop or into a I think the closest thing is you don't remember sea monkeys do you?

No they're a farm of brine shrimp that were sold they were sold as toys when we were kids but they're a type of brine shrimp that you could keep

them in a packet like seeds they would lay dormant for years and years on the shelf and then you put them into a little tank they were for kids

who weren't allowed to have fish tanks and then they would emerge as tiny little life forms these tiny tiny tiny little brine shrimp and that's the only

thing I can think of that is like an alive and moving around that that's close to seeds that's the only thing I can think of But I suppose it's really interesting as a scientist to, you know, it's kind of really, it seems a bit out there and, you know, why are you asking these questions?

But it is really fascinating to understand how do they do it? You know, how do these plants that live in the most extreme environments, you know, the top of the mountain, low oxygen pressure or at the edge of an Antarctic seashore with freezing temperatures and high salinity? How can they survive? And if you can understand that, you know, for the living world today, then you can apply that knowledge when you're studying fossils in the past and you can begin to kind of build up the story. Gosh, how did plants transform Earth from, you know, an environment that was just filled with bacteria and, you know, simple, single-celled organism to actually oxygenate the atmosphere

and build soils and build habitats and engineer, you know, this bare earth to something thriving that then allowed other organisms, you know, to follow and to, you know, to produce what we have today, this incredibly biodiverse world. I heard that trees, trees caused an ice age. Is that true? It's a two-way thing. So partly, yes. So living things shape. the atmospheric composition, and the atmosphere will affect what living things can thrive. So a lot of what I do is studying the interaction between the atmosphere and plants. And so, you know, how could trees cause an ice age?

Well, if trees are locking up lots and lots of carbon, like they did in the Carboniferous, And it's partly because maybe there weren't fungi to decompose that lign in the wood. But it's also partly because it was really wet and hot time. And these swamp systems were just over the whole world. So if you've got loads of trees sucking up loads of carbon and that carbon isn't being released back to the atmosphere, then you can bring the carbon dioxide level so low that when it rains in the Arctic and the Antarctic,

it will freeze and it will never thaw and that's an ice age. But I don't think trees alone did that. But you need a lot of trees and a lot of swamps to definitely contribute to causing an ice age. But not alone because there's other factors as well that are important. If you were given the power tomorrow, okay? Because we know at the moment, like the climate is warming, okay? It's really, really hot and it's dangerous.

Yeah. Using only, we'll say, natural methods, what would you like to see change in the world tomorrow if we were to cool the place down or to improve things? Oh, that's a hard question. Well, I think the power of biodiversity is incredible because we do know that in pristine wilderness areas, the soils and the vegetation itself

in those really undisturbed ecosystems hold more carbon than any ecosystem where there's been a human intervention. That's mad. Why is that? So you mean so a soil whereby you have a diverse, so loads and loads of insects,

a very diverse ecosystem, that soil will hold more carbon. Yeah. Why? As opposed to we'll say, I don't know, a field full of grass that a man is planted

or a human is planted. As soon as you disturb a natural environment you're going to you're going to lose things from us and if you lose some biodiversity

then you lose some of the capacity of the biodiversity in the soil which is doing all that good work of actually locking up carbon and actually what we know from the data is that we know we've added loads of carbon to the atmosphere

burning fossil fuels burning coal, Western industrialisation and you know we're really trying now to stop that but what's extraordinary is that one third of the carbon that we have released has been taken up by the oceans and one third of the carbon we've released has been taken up by living ecosystems on lands

like, you know, bogs, swamps, forests, grasslands, huge amount in grasslands, natural grasslands. So what we do understand is if the maintain and you restore biodiversity and nature, you maintain its ability to act like a sponge and take up carbon. So it's kind of like a win-win. If we have these policies that are positive for biodiversity, then we're also going to have a positive for climate because these areas are going to be the ones that suck up carbon. So even something like, like I know that all Ireland pollinator plan has been a really good success.

My buddy Collie, Collie, who you might know, because he works up in Trinity, Collianis. Yeah, Collie Ennis, yeah. Callie, oh God, Callie said something to me about six months ago, which was the first piece of good news I've ever heard around the climate.

He was looking at the amount of pollinators. And basically, this year, in a month, he had seen more pollinators than he'd seen in the entire previous year. And he didn't, like, he doesn't have the data to go, this is exactly why. But his hunch was definitely, we're seeing the results of this All-Ireland Paternator Plan. We're seeing the results of local councils going, do you know what, leave that roundabout alone.

Or plant some natural wildflower, some native wildflower. And it's been so positive. I had a little patch up my back garden. I'm talking six feet. Yeah. And I planted proper native. wildflower. Like, I didn't just get, I know sometimes when you go to the garden centre and get native wildflower that it may not be native to here. It could be native to Poland or wherever it came

from. But I got native to Limerick wildflower. And just in that six feet of garden, a year later, I was seeing insects that I'd never seen in my entire life. You're absolutely right. And Colley's right. I think the All-Ireland Pollinator Plan, which was, you know, developed. by the National Biodiversity Data Center and also Jane Stout, our VP of Biodiversity in Trinity, that has been so positive for biodiversity and also the follow-on no-mow-may policy. Such a simple intervention, don't mow your grass

or plant a high diversity of wildflowers. And it's, you know, through their hard work has really been adopted and the buy-in from councils all over Ireland and I think people are becoming familiar now with basically going past a roundabout and initially probably thinking

oh that's messy that looks unkempt and realising actually no this is so positive for biodiversity like in Trinity we had a no-mo policy in the front

sorry there's a bit of a noise it just started mowing outside but But we had orchids that came up in front square that turned out to be exceptionally rare. And these orchids had obviously been in the soil with their fungal partner. Were they indigenous? No, no, actually, it turns out even more exciting that they are a new, an expansion, probably a population of orchids from Wales that is now also present in Ireland

and we're actively studying those. But that was really extraordinary, this really rare orchid that comes up because we're not mowing the grass there in Trinity for a month. Just actually, because I used the word with the indigenous there and I want to know about what that means in terms of plants and biodiversity. Like I went on a sycamore tree rabbit hole there two weeks ago

because sycamores are everywhere. Ireland. And I was shocked to find out that, like, they're not from Ireland, that sycamores have been in Ireland and the UK. I think it's about 500 years. I think they came over with the monasteries. And what I ended up finding out was sycamores, they're from very high mountainous regions in Europe. And in the sycamore's natural environment, it has to, there's a lot of competition. it grows in large forests and it's very opportunistic if a bit of sun comes through

the sycamore will grow but basically because its environment is so tough that's why it needed the samara the spinning seeds that could travel for a long distance that sycamores come from a tough environment but then when the sycamore came to Ireland it didn't have the threats to its existence that had in its indigenous

environment. So when it came to Ireland, it thrived completely. Same with the UK. It thrived. But then I learned that the sycamore would now be considered native. It's part of the crack out there. It was once invasive, but now it's not. However, the amount of biodiversity that a sycamore holds, it's nothing compared to when it's in its indigenous environment, that sycamore is full of biodiversity. Whether it be fungus or different insects or mammals that live in the tree. But then when it comes here to Ireland, it only supports maybe 15 or 16 species. Yeah. And that completely changed how I'm like, oh, wow, I thought when I see sycamores,

it's like, oh, lovely, I'm out in nature. And now I realise, no, this was once invasive, now it's native, but you're actually seeing a bit of biodiversity collapse when you see a sycamore, as opposed to an indigenous oak that would have once been there. Yeah, so in a way, it is. Like, what is native, what is invasive, what is non-native, but not invasive. It's quite complex.

And I suppose we use a human construct for all of it because, you know, nature doesn't necessarily respect political boundaries. And we're an island, so we can kind of maybe more easily define what is native than other places. But typically, to be native, like we have over 1,200 species, species of plants, vascular plants, and then at least 800 mosses in the native Irish flora. You have to, as a plant or an animal, you have to have been evidence to be continually present in Ireland since the last ice age. So over about the last 10,000 years. Yeah, to be classified as native. And then we have two distinctions.

We have species which are... You know, they maybe have only recently arrived or arrived a thousand years ago. So technically they're not native. But they're also not invasive. So they're not damaging the local environment, the local habitats. What would stick out to you there as a big example of that now? What jumps out as this one is not indigenous, but it's doing grand. Yeah, the one that comes to mind is probably a bit obscure.

So in all the hedros, we have this plant called Alexander. It's one of the earliest plants that comes out in the hedger. Idros all over Wicklow, Wexford, it's really smelly. The Normans, was it the Normans? It was, I think it was monastic. Oh, okay. Yeah, but it came in as a cooking, you know, we used to cook it like a celery. And it isn't native, but it's accepted, and now it's kind of part of the natural flora.

But then we also have plants and animals, of course, which are non-native and they're invasive. And they have, you know, they thrive so well. they haven't got a natural predator or a natural fungus that would keep them under check and they are damaging to our local biodiversity and we have programs obviously to try and keep those under

check. Can I tell you what one thing there that might interest take, so I was looking loads at two things. First off Giant Hogweed, right? Yeah. One thing I found fascinating about Giant Hogweed is like I'm not a big fan of Giant Hogweed because it's legitimately dangerous, you know? Yeah, it is, yeah.

It can blind kids and stuff. But I went on to biodiversity maps.a.e. I think that's the name of the website. And I looked at the pattern of giant hogweed in Ireland. And I'm like, this fucking map reminds me of something else. It was the map of the plantations. The plantations after the 1500. So I started referring to Giant Hogweed as product.

footsteps. Because if you look at the literal plantations, that's everywhere where the giant hogweed was. And what it is really is it's a map of wealth. So where you had the Protestant descendancy and the gardens, they were the ones who fetishized this giant hogweed. And that's why you see that pattern. And then another one, and I found this really fascinating. I started looking at Japanese knotweed. Yeah. And so Japanese knotweed, again, which is a big problem, that comes from volcanic soils in Japan and it loves volcanic soils and in those volcanic

soils there's heavy metals there's lead and mercury and stuff that comes out of volcanoes and the Japanese knotweed grew in an environment where it can tolerate these otherwise toxic metals but if you look at where the Japanese knotweed is thriving

I refer to this as Thatcher's footsteps and Reagan's footsteps everywhere where Reagan and Thatcher shut down industrial areas. So it's in the Rust Belt of America. Yeah. Also the east end of London where you used to have petrol works, gas works, anything with heavy metals in the soil. Yeah. When Reagan and Thatcher got rid of the industry there, you were left with toxic soils.

And that's where the Japanese knotweed appears to be thriving. Yeah, it's incredible. The Japanese knotweed thinks it's in. volcanic soil but it's like it's not it's it's they were they had petro works here it's amazing you often get invasive plants following yeah really harsh industrial landscapes all also you see oh really do yeah so there's other ones yeah so sycamore is a railway one too actually yeah yeah so often i thought initially you're going to say it maps along the railways in ireland but um isn't it incredible really that there are again i know i'm biased about plants but isn't it a

that you know there are some plants that can live in the most toxic environments and they can thrive there and we call them phytoremediators so they can actually clean up the soil and what they do is they'll take up all those horrible metals and mercuries and they'll put it they'll compartmentalise it so they put it somewhere in their cell which isn't toxic to them they'll use that as an anti-herbivory defence so anything that eats them will be killed or poisoned. Really? Okay.

Yes. So they can use these heavy elements to their own benefits so they're not eaten. They compartmentalise it so they can thrive and we actually have a lot of plants that can be used to clean up these industrial sites and so what you do is you grow the plants and you harvest the plants and incinerate them. Go away. So people are doing this?

Yeah. And you can actually also use plants for it's called phytomining. So you know we have this big issue now with rare earth elements if we want to, you know. Oh, go way. There can use plants to get

like all these things that you have to dig into the art. Lithium and silicon and, you know, so you can, there are plants which will take up these rare earth elements. They're tiny trace amounts in the rock. The plants get them.

They often use a fungal partner and they break down the bare rock, take up these elements and use them for their own purposes. But there is a potential to actually use these plants now for phytomining. Probably not as it's going to yield as much as industrial mining, but it's a lot less harsh on the environment. Just another point that relates to that because what I want to ask you next is because I want to ask you about how maybe mythology or folklore might work alongside what you're doing. And what just jumped out at me there is

so there's the Shleve Mish Mountains down in Kerry okay? Yeah. Just beyond the Shleve Miss there's this area called Glawn the Gelt and Glawn the Gelt means

Valley of Madness, okay? And if you, in Irish mythology, this place pops up and I'm talking stories that could go back a couple of thousand years. In Irish myth, this was a place

where people went if they suffered mental illness of some description. Yeah. There used to be like King Sweeney King Sweeney used to hear bells and think that he was a bird and then finally he found peace

living in the Valley of Madness right? Down in Kerry and this stayed and stayed in the mythology for years and years and years right up until the 70s people who would have had bipolar disorder would visit the Valley of Madness and Kerry and they would eat the watercress

or they would drink from the well that's there and then in the 90s they studied the water in the well and it had a shitload of lithium I was just going to think, is it lithium? It was lithium. They found lithium there. And the watercress specifically, this watercress was taking lithium out of the water. And then when people were, and lithium is used today.

If someone has bipolar today, they would literally be prescribed lithium. So it's an example there of that story was there in the mythology. People knew it already. They just couldn't express it in a scientific way. But because you're dealing. with, like, do you ever find anything from mythology or folklore which would help the work that you're doing in trying to understand ancient or older plants? Yeah, in my work, not at the moment, but I think it is so important.

So, like if I ever give, you know, a walk and talk, a botanical tour or I would always try and, you know, read the books on the Irish, folklore, the historical references on how these plants were used medicinally and culturally in food, in divination, you know, it's so important because I think it connects

us to the past and I think you're absolutely right that you know, in a way botany was the early medicine. Yeah. So it's absolutely our loss if we don't actually

use these old culture. references and knowledge and incorporate them into modern science and use it as a guide to, you know, test hypothesis. Is there lithium? Can we use a x-ray to test the levels of lithium in these watercrest plants? And that means it's also in the rock. What was the rock? You can work with the geologists. You can, you know, so if you're studying what's called economic botany, So plants that have an economic value, so medicine, anti-cancer, you know, something for mental health, then a great source of information is actually to go to the cultural references. Like, for example, in herbarium, in Trinity, we have like 500,000 dried plant specimens. the oldest specimens in the collection were from 1728 and they were collected by a man called Threlkeld.

And he was the first, I think, to record the Irish names of all of the plants. And he found the plants in the markets from the plant women. And they would bring up the plants from their land up to market in Dublin. and in the Irish name is often, as well as the place, there can also be the use, and that links you back to folklore. Yeah, so I think it's really important on so many levels, you know, to use this knowledge in multiple languages because often you need to access it through the Irish language

rather than what we would typically use in science, you know, it should be the formal scientific name in Latin or Greek. Because the other thing too is I was thinking of how somebody somebody working in myth and folklore or even just the names or the language could consult with you. I mean what's jumping out

immediately for me is like I know that so Mayo Mayo means plain of yew trees and I know that dairy means an oak wood so they're in the names of places in Ireland are referring to forests that effectively no longer

existed. Yeah. But sure Of course, the best person to go to is you, I mean, to yourself, I mean. Yeah, yeah. So what you can do is you could, for these places like Dara or McDara, you know, all of these associations, you could actually take a core of peat or you could take, find a little hollow of sediment in a limestone pavement. And you take a core and often use a kind of a piston. And the core could be maybe one meter long or five meters long. And it gives you a record of sediment from anywhere between the last thousand years and the last 10,000 or 15,000 years.

And then what we do, and lots of my colleagues as well around Ireland, around the world, you would take a little bit of sediment, you'd put it into horrible acid, hydrochloric acid, hydrochloric acid, and you'd extract out the pollen. and because we know what the pollen of an oak looks like and we know what the pollen of a pine looks like and the pollen of a sycamore you can actually reconstruct the history of the place the forest, would they open, were they closed,

were they dominated by oaks, when did beach come in, is it native? And the whole vegetation history of that place can be reconstructed. And you can, and people as well, I'm assuming. Yeah, yeah. Again, taking it back to Maita, and folklore. If I read the Lauer Gavala Aaron

that's written maybe 1500 years ago by monks and it's their version of the history of Ireland but they mention I mean they're using myth they're saying the first people came from somewhere around Spain and that's just the story we have in a book that's

1,500 years old but I mean would you not see plants from Spain then that could do you know what I'm getting that? Yeah yeah. Do you ever see like you ever look at the record and go, why is there a bunch of plants here from this other part of the art and does this tell us about human migration to Ireland a couple thousand years ago? Oh yeah, that's so interesting. So the thing that comes to my mind is the strawberry tree and it's kind of related to

heather and it's got little white flowers and it's got these, it's quite unusual, it's got these red, round fruits that look like a round strawberry and the name in Latin is called Arbutus Unido and Unidomines. only once because if you eat, you know, it looks lovely, you eat it, be and eat it once. It tastes horrible. But strawberry tree occurs in the west of Ireland. Native, we think it's native, but maybe it wasn't. The only other places it occurs are in Portugal and Spain. And how did that happen? How do we have what this is called a disjunct distribution? So a tiny little pocket in Ireland and then the closest population, Spain and Portugal. Now, one of the hypothesis,

which is really intriguing and compelling. And this is by a botanist in Galway, Michelin Chi Skeppington. She suggests that the strawberry tree was introduced as a plant that was in maybe a beer or an alcohol or somehow associated with alcohol from Spain and Portugal. And it's a linker to people who came to the west of Ireland. And so that's one theory. Now there's other theories that this strawberry tree is there, not because of the people,

but because it's a relict from the ice age. For some reason, there must have been this little microclimate. Most of Ireland was covered in a giant ice sheet 18,000 years ago, but for some reason, this little strawberry tree survived in a population. And so there's two theories, and they're quite different. But we can use science to test those, and that would typically be, we'd use genetic methods. and that would go to a whole other department like genetics

or maybe plant science genetics to test those different theories. Here's one for you. So there's this bog body called Clonnie Cave and Man, right? Found in 2003. And they reckon Clonnie Cave and Man is, we'll say, 2,000 years old. Yeah. But the big thing with this bog body is that he had hair gel, right?

2,000-year-old hair gel. Hair gel, yeah. And the hair, it's, the hair gel was made from resin and they know that the resin comes from trees that were in the north of Spain. So that told us, okay, first off, this person was wealthy. Yeah. And it told us so much. And secondly, he was, whatever was going on, we now know that 2,000 years ago, this Ireland probably had some type of dealing with Spain. Yeah.

Like, would someone come to you with that resin? Because resin is trees. Yeah. Is that your job? So they wouldn't come to me, but they'd definitely come to a botanist. So a botanist who is trained in genetics. So there's loads of great botanists in Ireland, all the institutions, who would be able to, let me think, what would they do?

If they could extract ancient DNA, so they could also go to a geneticist, knowing the DNA, you could build a picture of the DNA types, they're called haplotypes and sometimes they're distinct there's a Spanish type and there's an Irish type and there's a Welsh type and you can basically build the map doing the

genetics of the ancient DNA and work out okay where did that resin come from another way to do it if you couldn't do DNA is you would maybe look at the chemistry and sometimes certain trees will always they have a very

different chemistry and if it was a very rare tree that you know today or even in the past only occurred in a very small population, you might be able to link it back to that chemistry. So typically what we would do is we'd use, you kind of work in a team of lots of different scientists, multidisciplinary team, and you'd probably try and answer the question using all the different specialisations. One thing I'd love to ask you to is, and I want to find out if this is real or not, is I've often heard Ireland referred to as

we're actually a rainforest that this country is a mid-Atlantic rainforest which is weird because I'm looking around and I'm like I don't see any fucking forest like are we really a rainforest and humans have just gotten rid of all the trees so we do have rainforest and really

how do you define a rainforest well you have to have at least at least 2000 500 millimetres of rain of year. So we definitely have that on the western seaboard. And then there's two types of rainforest. There's the tropical rainforest that most people are kind of familiar with. You know, we've heard about it.

We've read about it. Some have been lucky enough to be in it. But then we have another type of rainforest that's called a temperate rainforest. And that would be not in the tropical latitudes. So not in the low latitudes, but, you know, latitudes of about 40, 50 degrees north and south, but mainly north. And so Irish latitudes. So there's little slivers of temperate rainforest on the west coasts of America.

Think of like Seattle and Oregon. And the west coast of Ireland, the west coast of Scotland. And these are usually coastal strips where you've got moisture coming off the ocean. and as soon as it hits land it rains out and by the time it gets further in land there's not as much precipitation so rainforests are kind of restricted climatically to basically strips

but a big question is how we know today we only have a remnant so it was much more extensive in the past and when you say past like when like when pre-human change of the landscapes So is that pre-eyed? No, no, I think even more recent. So it would have been much more extensive like 5,000 years ago, 4,000 years ago.

So what you see when you look at the record of, you know, those sediment cores I was telling you about, you can see evidence of weeds of crops. And you can see the pollen of those weeds suddenly appearing. So things like, you know, ragwurst and. I can't think of any others offhand that appear. But you also get evidence of fire so you'd find charcoal. So you can actually

see the signature of man's intervention on the land, you know, when we start to become a more arable agricultural culture. And then you know, the landscape changes and to the forest detriment.

But it's a difficult question because there's always a balance, isn't it? You know. Off the top of your head, like what areas of Ireland do you know of that would have definitely been dense forest that now or not? Well, that is a really interesting question and actually we are

we, there's lots of active science projects on this at the moment but you said the word dense and that's really interesting because how you could have, let's say we know the species that should they're in a temperate rainforest okay X, Y Z. If you see them pollen, does that mean it was a dense rainforest?

So what we are doing at the moment is we're trying to work out. I've got people in the lab and other colleagues. And we're trying to get an indicator of the density of a forest. And we're using light as a guide. So we want to try and work out was the canopy closed or open? You see the species? We think there was a rainforest there. but we're not really going to know

until we can reconstruct was it dense or is it just open because he need to be dense to be a temperate rainforest because even like if you like this is something I heard again

and again anything to do with mythology that's going back this far it's all guesswork because the monks wrote it down okay what we do know we'll say

pre-Christian Ireland so before 1500 years ago when Patrick came over we didn't have towns or cities. Instead, we had all of these petty kingdoms. And one theory is, because you kind of go, Ireland's a small country. Why did you need to have 30 or 40 different kingdoms? Like, could people not just get together? It's pretty small. And one theory is, it was so dense

with forests that pockets of people were kind of isolated. Yeah. So we definitely had forests over much of Ireland way more extensive than today so today you know I should know this it's like 1% I might be it's pretty bad yeah it's really low maybe it's 10%

it's actually 10% but we have only 1% of native forest left but how then do you assess the I suppose I'm trying to get at this Indigenous versus this is pretty recent stuff we're talking a couple of thousand years.

Yeah. Therefore, are we not living in a very barren, even though I can look out the window and I can see a lot of green, are we not living in a very barren, unnatural country full of human intervention, human intervention? Are we not supposed to have a hell of a lot more? Yeah, so our by, definitely, as in all over the world, we have not valued our biodiversity. And, you know, 15 species have gone extinct from the Irish landscape, plant species, for example. So they're gone.

You know, most people have no memory of them. How long are you talking about? What's the most reason you can think of? In the last human generation, the last two human generation. Oh, my God. Fifteen species. What one are you most upset about? Oh, which one?

I actually have never seen any of them live. I've only seen them dry, all of these. And actually I've done some kind of little artworks on these, you know, trying to think about them, you know. And was it like a Victorian? Did some Victorian pick them up and decide to dry them? Are you going back that far? Oh, yeah, yeah.

Yeah, no. So we have back to the, just in the 50s, 60s. So a lot, you know, why have they gone extinct? It's mainly land use change. So drainage has impacted a lot of them. things that love wet environments, you know, as soon as you dry a bog, as soon as you dry a wetland, then it's losing its habitat. Improvement, we call it agricultural improvement,

so that's enriching the land with nitrogen. And ironically, nitrogen is really good for your crops because crops are bred to really use the nitrogen and thrive, but high biodiversity ecosystems where you get low. loads and loads and loads and loads of species. These are actually the poorest environments. So our old meadows, the old practices, pre-industrialisation, would have been much more positive for maintaining biodiversity.

You'd maybe get 20, 25 species of grassland species in a one metre squared plus, whereas today we have one. But there's really amazing examples in Ireland of trying to take. take on these more historical practices of maintaining biodiversity because it's good on so many levels. You don't sacrifice your productivity, you boost your biodiversity, you boost the nature value, and you also capture much more carbon in the soil. Do you mean farming practices now?

Yeah. So incentivising farmers for a bit of rewilding or a few meadows? Yes. Yeah. And it isn't even rewilding. you know, it's more leaving space for nature. But it's really important also. I mean, this is getting well outside my comfort zone of topics.

I'm much more comfortable talking about fossils from 300 million years ago. But we can take off the academics hat for a little bit and just go for a bit of opinion. Yeah, but there's a lot of simple solutions, but absolutely farmers have to be paid for these. You know, so for all land use, it's so complex. and this you know we need we need to feed the world but we can't do it at the cost of biodiversity so for every plot of land you have this this tension of of multiple possible uses and you know it isn't a black and white issue you know it's really complex but so I think some of these demonstration farms which are all over Ireland like Byrne Beaux and

And all of these examples where it's nature, biodiversity, positive farming practices. And it's a multiple win. Win for productivity for the farmer, win for nature, and also win for carbon and keeping carbon in the ground. And does it mean like, okay, you're growing your turnips over here and you've got a field of cows over there, but this field here, you're just going to leave it be? Not even that extreme. I think it can be the hedgerows. And the buffer zone between the hedgerow and, you know,

so rather than leaving a really tidy clipped hedge where the productive crop goes right up to the hedge margin, you just leave a buffer strip and that buffer strip is left to your own mode or it's planted with multi-species swore. or it's planted with meadow or you introduce a lot of native Irish meadow plants into us and then you've got this great margin which is providing all food for all these insects

which are then pollinating your crop and you know so it can be really small pockets but that's a loss to the farmer so why should we expect the farmers to do that so you have to pay them for the loss of their crop so all of that is so complex and there's lots of great

science centres, right, research Ireland centres who are tackling this problem now and trying to address what is the best way we can use land and using our scientific knowledge and considering all the stakeholders. I'm going to ask you one last question because just it pertains to hedgerows. So my buddy, Mankan, Megan, who recently departed Mankan. Yeah, so sad. He used to, I know, it's a terrible loss to all of us but Mancon used to work with an organisation called Home Tree and they were

basically trying to plant native forests and one thing that Mancon used to say to me which fascinated me was he wouldn't simply just plant an oak he wouldn't simply just plant a native Irish oak what he used to do was he would look amongst hedroses

he told me he said the best way to find a little pocket of untouched actual native Irish woodland is you'll find bits of it in hedgerows. And I said, what are you doing in the hedgerows? And he goes, I'm trying to find not just like a little bit of an oak or a little bit of a tree that I can plant. I want the mycelium that's in the soil. So he was looking in hedgerows to find soil mycelium as well as the plants, as well as the trees. Um, is, is, because I'd never. thought of that. I'm like, oh yeah, how does that come into it? Like, is that... It makes a lot of sense. Would you agree with what he's saying? Oh yeah, absolutely. Because,

you know, you plant trees. It is not a forest. Think of what is a forest. When you can walk through a forest, a really old forest, you don't just see trees. You see anenemies. You see bluebells. You hear birds, you know, so the planting of the trees is the kind of the engineer of that forest. But then you've got all of these other things hidden, like all the fungi underneath. So hedgerows are actually, it's argued that they're kind of like the vestiges of our past landscape. Some hedgeros in Ireland are so old. They're hundreds of years old. And the higher the number of species you find in them, it's usually a good indicator that they're really, really old. I think they say one species per 100 year. Maybe it's 10 years.

And it makes so much sense because no one has any business. It's just an old boundary and it's an ancient fence. Yeah. And no one has bothered to go near it. Yeah. It's a super highway. Think of all the animals that use the hedgerows to get to forest fragments. But plants do that as well.

You know, we think of plants as immobile, but they are moving. You know, an oak tree will shed its acorn and that acorn maybe two meters away and then that tree will grow and that acorn will move another two meters. So it's slowly moving through the generations. So that's a brilliant thing that Mancon did. If he took the acorn with the soil, then he's taking the fungi, the mycorrhizal fungi, that will make this lovely symbiosis with the tree and it'll extend its whole root network out

to extract those elements from the rocks that we kind of talked about earlier. So, yeah, it's much more likely you will make a true forest or a woodland by doing that. Is ancient fungi your business? Not really. So ancient... I knew it.

So you have to stop at mushrooms. Well, you know, some of the fossils I've seen, like, I once looked at this really early land plant and it's called Rhinia. And it's from a famous fossil locality in Scotland. And I was looking at it's Stamasa. So this thing is so old. It has no roots, no leaves, just. a basically little stalk, but it has stomata, these breathing pores that take up carbon dioxide.

And coming out of the stomata were loads of fungal mycelium, like the threads of fungi. And that was 400 million years ago. And I'd never seen that in the living plants. You know, usually stomata open and closed just to taking gases. You don't usually see loads of fungi erupting from it. And of course, scientists who've worked on it since, who are expert in fungi, they've worked out that, you know, we always talk about plants. They're so important to terraform earth, but they couldn't have done it without the fungi. They absolutely could not have done it. So arguably fungi probably even more important. But the partnership, the symbiosis between the plants and the fungi, is really key.

The one thing, just I promise this would be the last one, but it harks back to the first ever question, because I didn't ask you this. So when we were talking about that, that ancient extinction of trees, that ancient extinction of trees, which is now coal, I heard that the lignum in the trees, which took the carbon from the atmosphere, the reason that did not decompose was because the fungi hadn't evolved yet that could decompose it. Is that bullshit? No. It's actually, and I didn't answer it when you first asked me. it's a leading scientific hypothesis. And if you look at the modern data,

so some people study evolution by looking at genetics, the genes in the living things today, and they build an evolutionary tree for the past millions of years. According to those guys, they accept us. They think that's true. Now, the other way of looking at evolution is you look at fossils, You look at what was present then and you build up an evolutionary tree

by building up that picture and the fossil peoples don't agree. They think it's wrong. So I would say the question is still kind of an active area of science and it's really intriguing. Did we get coal swamps which formed coals

which we then burned and changed the climate because there weren't fungi to decompose them or was it just climate at the time? And I think it's still an active form. various science. Is it fair to say that at one point trees were like the plastic of now, that trees were these things that couldn't decompose, like plastic? Yeah, because lignin, lignin is wood and like in all paper mills, it's the bane of the paper mills, it's chemically really, really, really difficult to break down. And actually, if we did not have the fungi today that could break

down wood, we would be we would be neck deep or above our heads deep in un-decomposed trees. And there'd be fuck all carbon because it'd all be stuck down in the earth. Yeah, and then we'd have higher oxygen.

So, you know, so I suppose we have to try and capture some of this basic understanding and, you know, to come up with solutions for climate change in the future, but that's a whole other conversation. But yeah, yeah, Lignin is the plastic of the natural world.

It's so resistant to break down that there's just a particular fungi, just some and bacteria that can break it down. And that totally makes sense because if you think you grow to, you know, 50, 60 metres tall, you have to be mechanically really strong. And the side, the drawback is

it's going to be hard to break it down once that tree falls. Okay. Professor Jenny McElwain I could talk to you for hours and hours I don't want to take any more of your time but I just want to say thank you so much that was a fascinating conversation

Yeah and thank you so much as well that was grateful And thank you for your time Professor Jennifer McElwain Professor of Botany from Trinity College That was great fun I hope you enjoyed that also

Go to Scienceweek.orgie engage with whatever they have going on in your local air area. It's an entire week. There's cracking events. I love that it's in November. It's one of the best. I don't know what I call it a festival. You could call it a festival. A festival of science and knowledge and curiosity. It's one of the best festivals in Ireland. I'm calling it a festival. Science Week that I e. And I'll catch ye next week. What a hot take. I have a few things bubbling away. In the meantime Rub a dog Genie fleck to a swan

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