S1 #2 | Trees: should we just plant more?

S1 #2 | Trees: should we just plant more?

Contents: introduction, guest appearances, further reading, transcript, sources, credits

"The jingle which everyone quotes is the right tree in the right place" (Harriet Rix)

At first, the clear need for carbon removal begs the question - isn't that what trees do?

And they do - amongst a whole host of other benefits that they bring to our lives (tree-huggers exist for good reason).

Yet human activity certainly does not always display our gratitude for the value that trees bring us. With continued deforestation, raging wildfires and rising storm damage, our forests are facing a tough time.

So it's simple - plant more trees and protect the ones we have?

Well, sort of...

In this episode, Tom and Emily work through the complexities to understand the role that our forests may play in the carbon removal puzzle.

This episode's guests

Many thanks to our excellent guests in this episode:

  • Gert-Jan Nabuurs (Leading author on IPCC Report 6 for Land Management & Professor of European Forest Resources at Wageningen University)
  • Diego Saez Gil (CEO of Pachama)
  • Harriet Rix (Tree Science and Research Projects Manager at the UK charity The Tree Council)

Our Reading List & Sources

Planting Trees Won’t Save the World
2. Why not just trees?
Carbon180 Deep Dives
2. Why not just trees?3. Why not just nature?4. Can we do better than nature?6. How to reimagine carbon?5. Can we engineer our way out of this?
Carbon Dioxide Removal Primer
1. Why negative emissions?2. Why not just trees?3. Why not just nature?4. Can we do better than nature?7. How to scale up?6. How to reimagine carbon?8. What's stopping us?9. What now?5. Can we engineer our way out of this?
Nature-Based Climate Solutions Are A Key Strategy to Reach Net Zero
2. Why not just trees?3. Why not just nature?
Microsoft Carbon Removal portfolio
2. Why not just trees?7. How to scale up?9. What now?
Earth has 'lost more than half its trees' since humans first started cutting them down
2. Why not just trees?
How much CO2 can trees take up?
2. Why not just trees?
Planting trees doesn't always help with climate change
2. Why not just trees?
The global tree restoration potential
2. Why not just trees?
Climate-smart forestry
2. Why not just trees?
How much can forests fight climate change?
2. Why not just trees?
Are young trees or old forests more important for slowing climate change?
2. Why not just trees?
2021's extraordinary wildfires have released a record amount of CO2
2. Why not just trees?
The world has lost one-third of its forest, but an end of deforestation is possible
2. Why not just trees?
A one tonne carbon tree
2. Why not just trees?
Elon Musk's XPRIZE announcement
2. Why not just trees?
How to Save a Planet: 20 Million Trees
2. Why not just trees?
Ecosia Regeneration report
2. Why not just trees?7. How to scale up?

Want the episode in text form? Click the arrow below.


Tom Previte 0:01 So Emily, I'm looking at a tweet. It's a tweet that Elon Musk posted earlier this year. And it says, quote, "A m donating $100 million towards a prize for best carbon capture technology." I think what's interesting is when I'm scrolling through the 10s of 1000s of comments that are on there-

Emily Swaddle 0:20 That's a lot. Jeez Louise.

Tom Previte 0:22 The first thing that comes up, first one, it's a tree. That's the answer. That's the first suggestion. And then, and then the next one, the next one, it's a picture of a tree, get that, with "you're welcome" underneath. And then the next picture that I'm seeing is a picture of a forest.

Emily Swaddle 0:41 These people on Twitter. Geniuses. So Elon Musk has said to them, I'll give you $100 million. If you come up with a carbon removal solution, and people have said "yeah mate have a tree."

Tom Previte 0:53 "Yeah, where's my hundred million?" And he actually replied some of them, which surprises me.

Emily Swaddle 0:57 What did he say? "Thanks. I'll plant some trees."?

Tom Previte 1:00 Yeah not quite. He said they are one of the answers but not the whole answer.

Emily Swaddle 1:05 Nice one, Elon. Thank you for setting us up for this episode so perfectly.

Tom Previte 1:09 Cannot wait to have you on the next season, Mr. Musk.

Emily Swaddle 1:14 We'll interview you soon.

Emily Swaddle 1:29 Welcome back to episode two of the Carbon Show with him, Tom Previte.

Tom Previte 1:34 That's me.

Emily Swaddle 1:35 And me, Emily Swaddle.

Emily Swaddle 1:36 Tom, I've got to tell you, I am actually superduper excited about this episode in particular because, confession, I love trees. Absolutely love them. And we're learning more all the time about ways in which being among trees and green space in general is so good for human health. I was recently reading that it's really good for kids who have ADHD. It's also good for patients who are lying in hospital beds. And if they look out the window, and they can see trees, it helps with their healing. Being amongst trees is good for helping prevent mental health problems. There's loads of things. And of course, it's not just about human health, that trees are essential for our environment. They contribute to natural biodiversity and healthy ecosystems. They help preserve the water, they clean the air of all sorts of pollutants. And - and this is why we're here today - they pull carbon from the atmosphere.

Tom Previte 2:31 From what you're saying, I'm struggling to figure out anything bad about trees.

Unknown Speaker 2:36 Yeah, I mean, I'm not sure there is anything. If you fall from a tree, probably really hurts. That's not so great. But that's literally the only thing I can think of.

Tom Previte 2:44 To stop us getting carried away, we should probably just focus on the carbon storage potential of trees for this episode, reckon?

Emily Swaddle 2:51 Yeah. All right. I mean, I will get carried away if you let me so yeah, let's focus ourselves. That works for me. How about we dig a little deeper and get to the root of all this, Tom.

Tom Previte 3:07 I'm shaking my head, but I'm so impressed at the same time.

Tom Previte 3:12 So to learn how trees can help us in our carbon removal journey, we spoke with three experts who work closely on this subject. And what's really interesting is that each is approaching this from a very different angle. First, we spoke with Gert-Jan Nabuurs. He's the IPCC coordinating lead author in the sixth assessment report for agriculture and forestry. That's a mouthful. He told us about the situation we're currently in and the direction that forestry needs to move into to deal with our carbon problem.

Emily Swaddle 3:42 Yep. And we also spoke to Harriet Rix, who was, until recently, science and research project manager at the Tree Council UK. Harriet talked about the risks that our trees are facing and how local efforts can really make a difference in getting them back to fighting fit.

Tom Previte 3:59 And finally, we spoke with Diego Saez-Gil. He's the co founder and CEO of Pachama. Pachama uses the latest technology to monitor how much carbon is stored in our forests. So Diego helps us understand how we can meaningfully measure their effectiveness as a carbon removal solution.

Emily Swaddle 4:17 Based on our conversation with these experts, we really want to get under the hood in this episode. Looking back at that tweet, everyone's default is that trees are going to save us so we want to know is tree planting and reforestation etc. is it really as effective as everyone thinks it is?

Tom Previte 4:39 Before we look at how we can work with trees to help us meet our climate goals, we should probably understand a bit about what they actually do.

Emily Swaddle 4:47 Good plan. Let's start from the beginning. Get to grips with the basics.

Tom Previte 4:50 We asked Gert-Jan to give us a bit of a science lesson.

Gert-Jan Nabuurs 4:53 You may know from secondary school biology for a plant to grow it needs carbon dioxide from from the air, it needs water, which it takes from the roots. With the energy from sunlight in a green leaf, a plant is able to make sugars out of it. So carbon dioxide plus water makes a sugar. And with the sugar a plant and a tree is able to make carbon chains, as we call them, basically the fibers in the wood. Fibers which you can still see in your furniture in the house.

Tom Previte 5:26 You know, the tweeters have a point. Trees don't just store carbon, they really are carbon.

Emily Swaddle 5:31 Yep, about 50% of them is at any rate. Something that I became more aware of speaking to Gert-Jan and the other experts is just how central trees have always been to the whole carbon cycle. We talk about pre-industrial carbon levels in the atmosphere being perfect for life to thrive and one reason for that is the trees were helping to keep the whole atmosphere pretty constant. So trees are doing more than just feeding themselves, They have this huge role to play on a planetary scale, in terms of what our environment what our atmosphere looks like.

Tom Previte 6:07 But as we know, our co2 levels aren't staying constant anymore. We then asked Gert-Jan what role trees are playing now that co2 emissions have skyrocketed.

Gert-Jan Nabuurs 6:17 We burn fossil fuels. From those emissions trees take up 15 to 20%. And that is an enormous role, the forest, the managed forests but also the natural forests have at the moment.

Emily Swaddle 6:31 So of all that carbon in the atmosphere, trees are already doing their absolute best to help us sequester 15 to 20%. We'd be even worse off now without them.

Tom Previte 6:42 Yeah and to me it feels like trees are just maxed out. You know, with this much co2 in the atmosphere and more going up every year, there's not much more that they can really do. To get a sense of why they're struggling. We spoke to Diego from Pachama,

Diego Saez Gil 6:56 In addition to burning fossil fuels, we are deforesting the planet, and it is estimated that we have lost about 50% of the forest, that used to cover the planet. We lost that carbon sink, and we lost that engine of carbon sequestration, because forests are capturing carbon every year as they grow. Right. And we continue to deforest. It would be amazing if that was a story of the past. But you know, if you look at tropical forests, the Amazon rainforest, Congo, Indonesia, and even, you know, frankly, Canada, Alaska, and the US, Europe, we continue to deforest, to replace with agriculture, or urbanization, or just to do timber harvesting in such an unsustainable way that we continue to lose those carbon sinks, making the whole thing worse.

Tom Previte 7:48 That fact just blew my mind. We've lost 50% of our forests. And it doesn't really feel like we're stopping anytime soon.

Emily Swaddle 7:57 Yeah, it's really sad and terrifying. Diego really highlighted the competing demands that our forests are facing, you know, whether that's land for agriculture, and urbanization, or wood for furniture burning and building,

Tom Previte 8:13 Diego went on to explain that this isn't just a disaster for our current and future sequestration potential, but has actually added a lot of co2 to the air.

Diego Saez Gil 8:22 And when you look at the charts of what are the sources of co2 emissions? Yes, the biggest part is burning fossil fuels, which we all know is the main cause of climate change. But about 30% of the emissions is actually coming from the land use when they talk about land use is replacing forests with agriculture, clear cutting forests, emitting all that to back to the atmosphere, and then doing another activity on the ground, like cattle ranching or agriculture, that actually doesn't sequester carbon, the way that forests do.

Emily Swaddle 8:56 This was something that I think we both needed to get our head around, because we see trees is getting cut down. And maybe the wood is used in some way. But I was curious to know how this compares to natural tree loss. When trees just die naturally, you know, I wanted to compare the journey of those carbon molecules and understand why deforestation is so much worse. So okay, here we go. In our first example, a tree just falls over in a forest, maybe it makes a noise, maybe it doesn't, who knows. And then it starts to decompose in its natural process. And that decomposition means that the tree is releasing carbon into the atmosphere. But because it's decomposing within its natural ecosystem, some of that carbon is also going to go into the soil. It might be consumed by other wildlife, and it will help fertilize the other biomass in that forest. In our next example, we cut down a tree and use it as a natural building material. For example, the tree could no longer continue to sequester carbon, but we have at least stored that carbon away. What's going to matter then isA) how long we keep that carbon locked up in the wood and B) what we do with the land we've taken the tree from. If we make something high quality that lasts for centuries, and grow more trees in its place, we can actually harvest the wood from forests in a way that doesn't cause a net loss of carbon and is pretty sustainable. But if we're making paper, or other products that quickly decompose, and if we're turning that land into pasture, or urban space, for example, we're really adding to our problem. And then obviously, if we're burning down trees, which often happens to make way for agricultural land, that carbon is being released straight back into the atmosphere, and the trees aren't there to sequester the carbon anymore, either. That really is the worst case scenario,

Tom Previte 10:56 totally. And even natural wildfires can really cause some devastation in terms of carbon storage. Up to mid August in 2021. wildfires across the world are estimated to release 4.3 gigaons of co2 into the atmosphere. And that's more than any country apart from the US or China manage to emit every year.

Emily Swaddle 11:17 Oh, god, that's so terrifying. I mean, it just goes to show how much carbon is stored in these forests. And what's at stake, you know how precious they are? Clearly, we need to do something about this and at the very least stop this process of deforestation and carbon loss.

Emily Swaddle 11:37 Fortunately, there are many people and organizations around the world who are trying to improve the situation. The Tree Council is just one charity working in the UK whose mission is to bring people together in a shared mission to care for trees and our planet's future. The Tree Council have recognized that this needs public support and community engagement. So we spoke to the tree councils, Harriet Rix.

Harriet Rix 12:01 We have 1000s of tree warden volunteers around the country. And they are working really hard to increase trees in their local area by lots of different means in a sensitive way, in a community led way. And we also give tree grants. And finally my particular area is working to make sure that tree diseases don't hit the UK because what we've seen is ash dieback wiping out millions of trees. And as a result, you know, that's having a catastrophic effect on both the levels of carbon captured by those trees and the biodiversity of the treescape in the UK.

Emily Swaddle 12:38 What Harriet's touching on here is valuing trees for more than just the wood they can provide or the land that they stand on. You know, it's that caring for trees and making sure that they are protected from disease, from destruction of other kinds, and also engaging local communities in that protection. Playing on this love of trees that I have professed, I know we all share. You know, many people around the world feel the same as I do.

Tom Previte 13:05 Yeah, it's clear that we need to protect our existing treescape and Harriet also mentioned replanting, and knowing that 50% of our forests globally have been lost just emphasizes the need for us to be kind of actively replenishing them.

Emily Swaddle 13:19 Yeah, this is vitally important. But Harriet explained that there are things to bear in mind as we do this.

Harriet Rix 13:25 The jingle which everyone quotes is "the right tree on the right place". And you can generally find a tree which is appropriate for that place. But there are some really, really notable exceptions to that. So there have been some very remarkable failures of tree planting over the last 100 years. One of the classic ones is the planting of Sitka spruce across the UK, which has led to some really negative environmental effects and possibly even some negative carbon effects. Another one, which was a cause celebre recently was a peat bog in Cumbria that was plowed up to plant trees and obviously with catastrophic loss of carbon. And there are other examples with grasslands where no trees should ever been planted because you lose species. And so always making sure that you're not jeopardizing biodiversity when you plant a tree is incredibly important.

Emily Swaddle 14:17 So when it comes to solving this issue with the help of trees, we cannot panic plant, as it were. You know, there's a whole thought process behind the right tree in the right place, as Harriet put it, and there's questions of how much land is needed, how much water is needed, particular species and in particular locations. And you know, trees are living beings. So obviously, each one is going to kind of vary a little bit as well.

Tom Previte 14:41 It does sound like something we should be leaving to the experts.

Emily Swaddle 14:45 Yeah or at the very least, we need to be listening to what the experts have to say about this. You know, when Harriet's talking about the right tree in the right place, she's not talking about finding one species and just running with it. This is a common problem in even well intentioned reforestation efforts.

Harriet Rix 15:00 The first issue is that if you get a disease in a monoculture, it sweeps through it and you end up with lots of dead and rotting wood, you probably can't use it for forestry. And it'll end up potentially releasing more carbon than it's captured, it'll end up being bad for the species that live in it. The other problem is through a biodiversity point of view, there are very few species that can live with just one tree. So most pollinators, for example, will need the plants that live under a range of trees, and will need that kind of mixed condition that exists most of the time in nature. And the third interesting emerging piece of evidence is that monocultures capture less carbon. In the long term. If you plant a mixed broadleaf woodland, you're going to capture the most carbon.

Tom Previte 15:46 You know, this was something that was really news to me, when we first started doing this podcast, and a monoculture is essentially a plot of land where you plant the same species could be a particular tree or a crop. But Harriet highlights the real dangers. Not only are they bad for biodiversity, but monocultures have actually been known to release more co2 than they sequester. And they're also not usually around long enough to lock in the carbon because they either fail or harvested quite quickly.

Emily Swaddle 16:13 The famous one is obviously palm oil, you know, planting palm plantations in places that used to be rainforests. That biodiversity loss is huge. And just saying, "yeah, we're planting a tree here, it's gonna be fine!" It's not like that's not making up for losing a rainforest. Another result of panic planting that I hadn't really looked into before is the loss of albedo.

Tom Previte 16:35 You're gonna need to run that one by me.

Emily Swaddle 16:36 Yes, it's albedo, not to be confused with libido, very different things. But essentially, albedo is the effect when sunlight is reflected off the surface of the earth, and it's reflected back out. So it's actually a cooling process for the planet. And there are parts of the earth where this is done very effectively. Areas like Siberia, which was previously icy tundra, now that the climate is warming up forests could in theory be grown in these areas, but that would actually cause more heat to be trapped in that specific local area. So if we're trying to plant trees, we shouldn't just plant them anywhere. Because forests are, of course, taking in sunlight and not reflecting it We have to be mindful of the local and regional circumstances, because planting forests in places that are normally reflecting the sun's rays back could have some serious adverse consequences for that region's climate and ecosystem.

Emily Swaddle 17:17 It really just makes you realize how complex this whole system is. If we're reforesting, we need to make sure that we're using the right species. And if we're aforesting - that is planting trees where forests wouldn't have existed before - then we've got to ask ourselves if trees are even the best thing for that land?

Emily Swaddle 17:49 Yeah, exactly. And as we've touched on, we don't just want these trees to be in the soil for one season, we need long term thinking here, not only because we can create stronger ecosystems and so on, but because we really do need a long term solution to our carbon problem. We want trees that can keep carbon stored, and keep storing it for many years to come.

Harriet Rix 18:12 One of the things that comes across in all our discourse about trees, is that people are always planning for, you know, the next 10 years of budgeting the next 10 years, they're planning till 2050. Whereas of course, a tree, you hope it's going to live for 1000 years. And so the more we can try and think on that timescale, the better it's going to be.

Tom Previte 18:41 So my takeaway thus far, is that forests have been incredible carbon sinks for millennia, and they still help us a lot. But in recent times, we seem to have been doing everything possible just to break them.

Emily Swaddle 18:52 Yeah, I agree. It seems that way to me to. It seems like part of that problem is that trees are not fast moving. And yet human society is so fast paced.

Tom Previte 19:02 And something we need to bear in mind is that forests have got economic value. They're important for societies. And we have to be mindful of that. Natural forests have so many benefits. But it's not just realistic to expect us to naturally, you know, reforest everywhere. We've got limited land on this planet. And we need space for agriculture and human habitation. And of course, we need forestry that's productive for things like wood production. And we need to do all of this in a way that restores rather than damages the planet.

Emily Swaddle 19:33 So how can we move forward from here? What are the next steps? Tom, help us to zoom out a little bit?

Tom Previte 19:39 Well, we mentioned the IPCC last episode, and earlier we briefly heard from Gert-Jan Nabuurs. He's a professor of European forest resources, and the coordinating lead author on the IPCC's sixth assessment report for agriculture and forestry. Gert-Jan works on a Europe-wide scale, and gave us an insight into what's happening across the continent with regards to our forests.

Gert-Jan Nabuurs 20:02 We know that with more co2 in the air, a tree starts to grow faster, the growing season is longer, we all experienced that the spring is earlier and autumn is later. So we projected a lot of more growth in European forests in our early studies. But things started to change in around 2010, 2011. We had these first signs that forests were also changing. We saw more damage in the forests, there was of course, fires have always been there but were increasing, there was storm damage, these so called natural disturbances seem to be increasing. State of your forests was changing. This sink as we call it was saturating; these trees were not sequestering so much carbon.

Emily Swaddle 20:48 Wow. So more co2 in the atmosphere should mean that forests grow quicker and larger, I suppose you could think of it as nature's way to restore the balance. But on the flip side, more co2 means impact on climate change, which increases the chances that trees might die, you know, from storm damage, or forest fires or other extreme weather events.

Tom Previte 21:11 Exactly. And in some cases, just like in the European forest that Gert-Jan mentions, that battle between increased growth and increased death seems to be swinging the wrong way. And as Gert-Jan pointed out, the many threats to our forests means that we need long term management.

Emily Swaddle 21:27 I find this a really interesting shift from the focus of planting trees to actually growing trees. You know, we talk so much about planting a tree. But actually the important thing is, these trees need to grow.

Tom Previte 21:39 Yeah, and tree growing, as we know, it takes a lot of time. And what we also know is that trees are most effective at locking away carbon as they're growing and getting bigger, and when they're growing at their fastest. So we need to make sure they get to that stage and don't just wither in the first few years.

Emily Swaddle 21:55 And I totally take your point, Tom, that societies all around the world really rely on these forests for all sorts of reasons, wood to burn to keep themselves warm, or for building materials and all sorts. And that's the value that those trees have for us. Unfortunately, they may have to cut down those trees and possibly burn them to get that value. And so we really need to help incentivize finding value in trees while they're standing, and actually going through their living process. You know, if we want them to continue to be the great carbon warehouses that they are.

Tom Previte 22:29 And we can't just turn around tomorrow and flip a switch and say that everyone can't chop down trees or have to manage their forests in a certain way. Because that's just not how things work. And it's not how we're going to solve all our issues.

Emily Swaddle 22:41 Yeah, exactly. And it's like all kinds of problematic as well.

Tom Previte 22:44 What we're really looking for then is a sustainable way of growing and managing our forests. One that's mindful to the needs of the people who rely on them. Gert-Jan explained how this is actually developing across Europe.

Gert-Jan Nabuurs 22:56 Before the COP21, this Conference of the Parties, we came up with this notion or the terminology of climate smart forestry, that it's not only mitigating anymore, but we certainly have to adapt our forests also to climate change. It really looks at the local circumstances, because every country in Europe has different forest, every country has a different culture of forest management. And you really need to look at the local circumstances what is best to do where.

Tom Previte 23:24 So the three core pillars that climate smart forestry revolves around are firstly, that reduction of greenhouse gases, which helps to mitigate climate change. Secondly, climate smart forestry is helping forests adapt, so to enhance their resilience. And the third is to have that active forest management, which is aiming to increase productivity and income on that sustainable level. So it's providing benefits beyond just chopping down and leveling a whole forest. Climate smart forestry is therefore this theory that aims to find the optimal combination of measures to maximize climate change mitigation, whilst considering those regional circumstances. And it strives to achieve possible synergies with other functions such as biodiversity.

Emily Swaddle 24:08 As we cover more ground here, it really feels like we've moved from focusing on the tree itself, to looking at the whole forest and even beyond. You might say, we're beginning to be able to see the wood for the trees. But really, I think this is a useful reminder that we can't be too idealistic or prescriptive about this process. We need practical solutions that work within that complex ecosystem, and indeed, the complex global economy.

Tom Previte 24:38 Yeah, exactly. And something that Gert-Jan really helped me understand is that we need to return to that idea of the carbon cycle. The main goal here has to be to restore that cycle and optimize it so we can deal with levels of atmospheric carbon that haven't been seen for millennia.

Emily Swaddle 24:56 Yeah, I think that's an excellent point from Gert-Jan. You know the natural systems don't ensure that the carbon is captured forever. That's not how they work. What we're trying to do here is restore those natural cycles to help them sequester the carbon that we've been throwing into the atmosphere and continue to throw into the atmosphere. So it's not about the perfect solution. It's about mending that carbon cycle to help it do its thing, you know?

Tom Previte 25:20 Yeah, it's about working with the forests as opposed to against them. And getting all that biodiversity and the other benefits that come with it. The benefits for all of us seem clear, and it really just feels like the least we should be doing if we want to deal with our carbon problem.

Emily Swaddle 25:35 The very least.

Tom Previte 25:38 It's not like I really needed much convincing before. But it does seem pretty clear from these conversations, that trees are just a good thing. And getting our forests healthy is just super important.

Emily Swaddle 25:49 Yeah, no argument from me on that one Tom.

Tom Previte 25:52 It's also clear that doing this is going to have a beneficial effect on carbon drawdown, and at the very least, stop emitting more co2 through land use change. But we've spoken a lot about how this is a natural and therefore unpredictable process, and also how trees and forests are vulnerable to climate change. So what I'm not so clear on is whether reforestation and aforestation are a viable, reliable, measurable means of drawing down carbon at that gigaton scale. How confident can we be that this will have a meaningful impact on helping us reach our climate goals? And have we even got enough land available?

Emily Swaddle 26:29 I think you're right to be skeptical, Tom, honestly. But to answer your last point first, yes, there's a lot of land out there that we could start growing trees on right away. With the right financial measures in place. Diego Saez Gil from Pachama gave a really good overview of this.

Diego Saez Gil 26:47 The good news is that we have an enormous opportunity for reforestation, with a billion hectares available for forest restoration without competing with other human activities. And the only thing we need to do is we just need to drive funding to do that reforestation, then also we need to drive funding to stop deforestation because there are many landowners who owned forests, who unfortunately, see it as a natural resource to be exploited and to, you know, gain an income on. If we don't pay them to not cut down this forest, they will, it will cut down this forest to produce timber and to do agriculture.

Emily Swaddle 27:21 What Diego is saying is that essentially, in order to protect forests, it's important to outbid other industries that want to cut down those trees to either you know, use the wood or the land, or both. So there's got to be a way of rethinking the value that trees can give us in order to protect them whilst they're still standing and still living. It's tricky, because when you cut down a tree, and say, This is how much wood it gives us, or this is how much land it frees up. It's really easy to quantify that and monetize it. But what we're talking about here isn't really economic value, its environmental value. And that is so much harder to quantify.

Tom Previte 28:02 I suppose from our perspectives, the big question is going to be how much carbon can these trees, these forests actually store? If we can work that out and work it out accurately? We might start to put a price on that cost, you know, of sequestering each ton.

Emily Swaddle 28:17 Exactly. Fortunately, this is exactly the work that Diego does a Pachama

Diego Saez Gil 28:23 I will say that probably the average tree on the planet is around one ton. There are some very big trees in the Amazon rainforest, some as big as the redwood of California, and some of these trees can be up to 10 tons of carbon, you can sometimes have up to more than 300 tonnes per hectare. So we're talking about the huge carbon concentration in a single hectare.

Tom Previte 28:49 Right. So for anyone interested, I was trying to figure out how much a hectare of land actually is. And it turns out, it's a bit larger than a football pitch. So that's 300 tons per football pitch and a quarter. That's a lot of potential.

Emily Swaddle 29:04 Yeah, I actually had no idea how much a hectare of land was. Actually though, Tom, we're gonna need something a bit more specific. Luckily, it's actually incredible how much data we can collect on trees. Diego talked about how Pachama combines satellite data and AI to estimate this carbon sequestration, not just within a single tree or a hectare of trees, but across whole forests.

Diego Saez Gil 29:30 We have very high definition images of the planet today coming from a lot of different satellites that orbit the planet. And we also have LiDAR, which is this three dimensional shape that we can produce of a forest by beaming lasers from an airplane. And then we have artificial intelligence that allows a lot of data to be analyzed, and then these algorithms learn and then can make predictions. We can observe trees in a forest and then with enough good training data, the algorithm can start to predict how much carbon is there in that forest.

Diego Saez Gil 30:09 Have you seen the movie Avatar? In the movie Avatar, there is this part in which they have this three dimensional scan of the forest of the planet Pandora. And then they actually use it not for good, right but we could some point have a three dimensional scan of all the forests of the planet and use that data to protect and restore those forests.

Tom Previte 30:28 I feel like we're living in the future. The more that we spoke into our guests, the more that I feel the split between the nature based solutions and the engineered ones that we will discuss, it's kind of a bit unfair, it feels like the nature based solutions don't really get as much kudos for how much technology they actually use. It's just really impressive.

Emily Swaddle 30:47 Yeah, it is it's super cool. And to a certain extent, it's vital. You know, using tech to quantify carbon on this scale, can give us an idea of the value we stand to lose. If we cut down these trees, as well as the value we stand to gain by leaving them in the ground and planting more trees. So Pachama works across the Americas. And the first part of its work is this data collection, which allows them to monitor how much carbon is being stored. But Pachama is also a marketplace where you can purchase carbon removal credits, which go directly towards preserving and restoring forests. This might be for organizations who want to support those forest projects, and who can buy credits which offset their emissions. The data collection side of things is therefore key. Because it creates a level of trust, you will know that your credit is purchasing the amount of carbon drawdown it promises. Because Pochamma knows exactly how to measure this. As we've touched on though, trees do not unfortunately, live forever, especially where humans are involved. So I asked Diego how they ensure this carbon is sequestered for the long term.

Diego Saez Gil 31:56 Imagine that you are a company in the US and you want to send money to help stop deforestation in the Amazon rainforest in Brazil or Peru. But how do you know that the money is actually going to go to the right hands, and it's going to cause the right impact? And that impact is going to continue to be protected for many, many years? It's difficult. Right? So the idea was, Well, maybe if we produce this, you know, real time monitoring, then more companies will say, Well, yes, that way, I actually do trust.

Tom Previte 32:33 This is so important. If I'm buying a carbon removal credit for my company, I want to be assured that this isn't going to be released, you know, next year.

Emily Swaddle 32:41 Yeah, exactly. You've got to have reliability. And it's so important when a lot of businesses are touting you know their carbon neutral credentials. And there is a bit of distrust in this process, the least we should be able to expect is that a credit is worth the amount it says it is and it's gonna last for a reasonable period of time.

Tom Previte 33:02 That is certainly not the last time we'll be hearing about permanence.

Emily Swaddle 33:10 You know, we started off this episode talking about trees as kind of single beings. And we've really progressed to thinking about them as part of an ecosystem as a forest and the cycles that are within that, like we said, there are so many other benefits to growing trees, trees are amazing. I continue to be a huge fan of trees. But when it comes to carbon removal, specifically, there are just so many things to think about, you know, especially if we're talking about all the carbon that needs to be taken out the atmosphere, and how much land we actually need in order to remove that much carbon.

Tom Previte 33:42 This is sort of like a key question that I have as well, that question about the land use, and there is a lot of uncertainty. And there's a load of different stats, I'm actually just looking at the fantastic carbon dioxide removal primer, which is just this group of experts that compiled a really helpful report, which is available online. But it estimates that we're looking at to remove a single gigaton, that's a billion tons of co2 from the atmosphere, we're going to need approximately 27 point 5 million hectares of reforested, or a forested land. And that varies massively depending on the different factors. But it just gives you a starting point. I don't want to figure out how many football pitches that is but it's a lot.

Emily Swaddle 34:25 Well, actually, I've looked it up so I don't know in football pitches, but 27 point 5 million hectares is equivalent to the entire size of the UK plus half of Ireland, or it's also just a bit bigger than the size of New Zealand. That's a heck of a lot of land.

Tom Previte 34:45 That is a lot.

Emily Swaddle 34:45 Yeah, it's loads. And we're currently releasing about 50 gigatons of co2 equivalent into the atmosphere every year.

Tom Previte 34:53 And it's worth reiterating that we can't just plant forests everywhere as well. Some regions we know are going to be particularly good, like Europe or parts of China or the US. But in many other parts of the world, it's just already got good forest cover or the land and conditions just aren't great for supporting it.

Emily Swaddle 35:11 Yeah, I mean, Harriet talked us through that, you know, you've really got to think about where you're planting these trees.

Tom Previte 35:15 I think for me, a big concern is just that human element of control. Like we're not going to control whether it rains one week, or if they're a forest fires the next. And although there is a scale potential there, and the models that we map out show that we can sequester a whole load of carbon through reforestation and afforestation. Who knows what impacts could happen in a changing climate.

Tom Previte 35:37 Trees to me, trees aren't necessarily our 2030 goal. Trees are a long term thing. And they don't necessarily have the impacts that you might want from them from day one. But fast forward a couple of decades and it's perhaps a different picture. What I am excited about is the potential to flip that script, incentivizing people to manage and protect forests, as opposed to cutting them down, and actually being rewarded for protecting them rather than removing them.

Emily Swaddle 36:04 Yeah, Tom, I totally agree with your concern about the time frame, we're just relying on trees to fix this problem when the forests aren't even in a good condition to be able to do so. And that's going to take time to get forests back to a state where they can help us with this issue in a way that we really need them to. And at the scale that we really need. Honestly, the thing is, is that trees are very much a part of this, but not necessarily the whole solution. And I think something else that really concerns me is that there are a lot of companies out there that say, you know, we plant a tree every time you X, Y, Z. And that's great, because we love trees. And we've talked about all the amazing benefits. But you can also see how it can potentially be a bit sort of greenwashing. You know if that tree planting is simply just planting a tree anywhere, or planting the wrong kind of tree, or planting the right kind of tree in the wrong place, or planting a tree and it burns down or then they cut it down. And that's not what we need. The thing that's really exciting for me, we've been talking about valuing trees for more than just the wood that they are and the land that they stand on. And for me when I picture what it could be like if we did value trees and nature in this new way, based on what they actually do for the planet and what they do for us. I don't know, maybe it sounds like a hippie utopia. But I love that. I would love to live in a hippie utopia wonderland, you know, where we all love trees just for being trees and just living. And I feel like that could really affect our relationship, not only with trees, but the whole environment. And that to me is it's really exciting to think about that.

Tom Previte 37:41 That sounds like a bit of an homage you're paying trees right there.

Emily Swaddle 37:43 Yeah. I mean, they've had a tough time of it that deserve a bit of love.

Tom Previte 37:48 Yeah, now I'm just wondering what other parts of the planet we need to be paying attention to

Emily Swaddle 37:51 Patience, Tom, we'll get there. In the meantime, I think maybe we can just leaf it here for now. It just comes to me, it's my genius.

Tom Previte 38:48 Thanks so much to our team who make this series possible.

Emily Swaddle 38:52 Our researcher and fact checker Henry Irvine,

Tom Previte 38:54 our composer Sam Carter,

Emily Swaddle 38:57 our graphic designer, Rekai Campbell,

Tom Previte 38:59 our editor Mercy Barno,

Emily Swaddle 39:01 our producer, Ben Weaver-Hincks,

Tom Previte 39:04 our Project Manager Patrick Carter,

Emily Swaddle 39:06 and our executive producer Sam Floy.

Tom Previte 39:09 Thank you for sticking with us to the end of this episode of the Carbon Removal Show. If you liked what you heard, don't forget to subscribe wherever you get your podcasts. And if you've got the time to leave us a review that would really help us out.

Emily Swaddle 39:21 Next time we're going to be talking about the place where trees live, not the forest but the soil. We'll be diving into some of the problems caused by agriculture and as always checking out some solutions.

Tom Previte 39:33 For more information about carbon removal, visit restored.cc See you next time.

Emily Swaddle 39:38 Thanks for listening!


The Carbon Removal Show is a Restored.cc and Cofruition production. We are sponsored by Patch. Here's who made this episode happen:

  • Emily Swaddle & Tom Previte - co-hosts
  • Ben Weaver-Hincks - producer
  • Henry Irvine - researcher
  • Sam Floy & Patrick Carter - project managers
  • Mercy Barno - editor
  • Sam Carter - music producer