a woodland fantasy

How much does mass tree planting affect climate change?

The concerted effort to plant trees at scale didn't begin until the second half of the 20th century

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This is the full transcript for season 4, episode 1 of the Quartz Obsession podcast on tree planting.

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Nalis: A few weeks ago, a group of volunteers in Paris planted a mini-forest. It was all very cute. I saw some photos. There were a nine-year-old kid, a 79-year-old retired journalist, and a 31-year-old who said he was moved by the opportunity to be in close contact with nature. They were hoping that the mini-forest would help reduce the heat waves in Paris, but we don’t really know how much reforestation helps against climate change, and yet we’re often offered trees to offset our carbon emission yield.

You’ve bought a flight. Do you want to pay 10 extra dollars to plant a tree and vacation with a clear conscience? Good question. Do I?


The appeal of planting a tree makes sense. Amid the raging storm of climate catastrophe, adding new green things to the landscape feels like a wholesome concrete solution. No need for fancy policy talk or corporate regulatory mumbo jumbo. Just touch some soil, get your hands dirty, and one by one, we can plant our way to a climate solution.

But how much carbon can one tree possibly absorb? And is it necessarily a good idea to invest in tree planting initiatives? I am Annalisa Merelli, Nalis for short, and I’m this season’s host for the Quartz Obsession. Today: tree planting.


I’m here today with our brilliant editor, Samanth Subramanian, who’s gone on a deep dive into the word of tree planting and came out to obsess about it with us today. Welcome, Samanth.

Samanth: Hey Nalis. Glad to be here. I’ve just come up for air from the forest, so let’s talk.

Nalis: Usually when I have these conversations, the first thing that I’m curious about and I ask about is, what’s the history of X, Y, and Z? But it seems a bit weird to ask about the history of tree planting, because isn’t that something that we’ve been doing forever? Like, is there, to any extent, a timeline that we can trace?

Where did the push for tree planting originate?

Samanth: There really isn’t. I mean, if you track this back to the ancient Greeks as most podcasters like to do, the Athenians had this program called civic planting where they would plant trees in their agoras so that you would have shade on a hot day. But planting trees for shade was a particular kind of instrumentality, and so was planting trees for fruit. You know, you think of Johnny Appleseed, who really planted apple trees across several states only for their apples. So do we have to plant trees? We do need trees for shade, we need them for fruit. We need them for cover.


But the really big, concerted effort to plant trees almost at scale as part of an afforestation drive by companies and institutions—that didn’t really begin until the second half of the 20th century.

Nalis: But when did reforestation efforts actually begin? I mean, more specifically in terms of carbon capture.


Samanth: I mean, it’s only beginning in the 1950s that we begin to understand the impact that trees have on the greenhouse effect and climate change, and how trees soak up atmospheric carbon dioxide to diminish the effects of climate change. There was an American scientist called Charles Keeling who did a lot of work on this front, and he worked in the 1950s.

I always think, you know, of Dogmatix. I don’t know if you know this, Nalis: the little dog in the Asterix comics who cries every time a tree is uprooted? So those comics started coming out in the late 1950s, and by the 1970s, you have a kind of proactive protection of existing trees and planting of new trees, specifically with the view of tackling the Earth’s environmental crisis.


So, if you want to think of modern tree planting as a phenomenon, we are roughly at the half-century mark of that.

How planting trees offsets carbon in the atmosphere

Nalis: So what is the relationship between carbon offset and planting a tree.

Samanth: So a carbon offset is basically a way in which a company can make up for the emissions that it’s putting out there by either drawing down carbon in the atmosphere or finding ways in which to protect the environment in other ways. And so, tree planting is one of the several methods that companies resort to and possibly the most common method that companies resort to.


Nalis: And how did the science behind it develop?

Samanth: The science of what we call the greenhouse effect, which is behind climate change, is about 200 years old. There was a Swedish scientist called Svante Arrhenius who set out the principles along which the greenhouse effect operates. And, you know, he worked in the 19th century, but the knowledge that plants make their food by capturing carbon from the air in the process that we call photosynthesis is really old and really basic. Any biology student in middle school studies about this through their textbooks.


And so the connection between carbon in the air—or in the atmosphere—and carbon as taken up by plants is quite basic, and all it required was sort of a way to quantify how much carbon a tree soaks up over the course of its lifetime.

And so there’s like various estimates out there right now about how much carbon an average tree takes up. Obviously the bigger the tree, the more the leaves, the more carbon it takes in. But there’s roughly a sort of average that a particular nonprofit in the US puts out now, which is about 48 pounds of carbon per tree that it soaks up.


Nalis: So now we have an industry that’s trying to undo what other industries are doing. How did tree planting become such a big business?

The history of tree planting programs

Samanth: I mean, really this is a 21st century phenomenon. I think as pressures built upon companies to show their commitment to climate change or the fight against climate change, they started to reach for these tree planting schemes to burnish their green credentials essentially.


And the number of such schemes is too long to list. I mean, the most prominent maybe is the One Trillion Trees initiative, which is the brainchild of Marc Benioff, the billionaire CEO of Salesforce. That was signed into being through an executive order by president Donald Trump in 2020. One trillion trees! Keep in mind that our best guess for the number of trees on the planet around 10,000 years ago, before mankind even started farming, was 6 trillion. So we’re aiming to plant a sixth of that all over again.

Nalis: Do we have space for that?

Samanth: Well, apparently we do! We have to find it, but, and I’m sure Marc Benioff has ideas, but this is…


Nalis: He’s gonna come for your terrace. It’s gonna be like, “Hey, uh, do we need one here?” You know, it’s like… it seems like a lot!

Samanth: That’s absolutely it! I mean, you raised this, I mean, this is, it’s sort of fun to wonder about where these, where these trees will go because these massive questions of equity start to come up. So where are you going to plant a trillion trees? Well, mostly they’re going to be planted in erstwhile rainforests or jungle areas in Latin America and Africa and Asia. And who are you displacing by planting these trees? I mean, what kind of farming communities depend on that land as farmland? And so what you essentially have is local communities in the poorer parts of the world trying to tend to trees that have been planted to make up for the mistakes of consumers and corporations in the wealthy part of the world. I mean, it’s a massive inequity that is just being reinforced by these tree planting drives.


Nalis: So who else is a big player in the field?

Samanth: There’s so many, I mean, there’s the Bonn Challenge, which essentially is a drive to reforest 350 million hectares of land by 2030. There are campaigns with names like Trees for the Future and Trees Forever. The Nature Conservancy wants to plant a billion trees, although it’s unclear if these will be counted in the Trillion Trees campaign. There is a separate trillion trees challenge, which is being put together by the World Wildlife Fund and a couple of other nonprofits. Again, we don’t know if they’re the same trillion trees or they’re going to end up with 2 trillion trees.


So I mean, if you think all of these tree planting schemes put together… Right now on the planet, we have around 3 trillion trees, which is half the number that we had 10,000 years ago. And you have all of these various initiatives, and if you think about adding all of them up, even if all of them succeed, purely in a quantitative way, we’ll be back to a pre-agricultural kind of forest cover, which is the most unfeasible, absurd idea for the planet that I can think of right now.

Nalis: It’s like trying to erase our presence while trying to continue being as harmful as we can.


Samanth: Exactly.

Nalis: Is anyone making money off it? Like is any company making actually significant money planting trees?


Samanth: I mean, not significant. I mean there are companies that offer to plant trees for you. There are companies that offer to verify the companies that plant the trees. There are companies that issue offsets against trees. So it’s a really crowded ecosystem out there. But I don’t think anybody is sort of becoming a billionaire through this.

What is happening is that the billion dollar corporations and the multibillion dollar corporations are allowed to continue being multibillion dollar corporations because they depend on this tree planting exercise to absolve themselves of any responsibility towards climate change.


Nalis: I wanted to go back a little bit in like, you know, the early days of tree planting and reforestation specifically. How did that go from like a rebellious act into such a corporate mode of continuing the way that we consume energy and produce carbon?

The corporate response to climate change

Samanth: Yeah. The evolution of what you might call tree planting drives says so much about how our thinking about climate change has evolved. You know, tree planting is now so profuse, there was one survey in 2021 that found that the number of tree planting groups in the tropics alone has increased by 300% since the 1990s.


And some of these efforts are, as you say, extremely radical, politically speaking. Some… not so much.

So to take the radical first, if you look at Wangari Maathai, whom you mentioned, who started the Green Belt Movement in the 1970s—she was trying to get rural women in eastern Africa to plant trees near the villages. I mean, and she designed this not just as an afforestation scheme, but also as an educational and empowerment project. And so by the time she won the Nobel Peace Prize for this, in, I think, 2004, they’d planted 30 million trees! But there’s also dozens of other modern examples that feel much less revolutionary, right?


You have airlines selling you offsets when you book your ticket, promising to plant trees for you. Here in the UK there’s a company called Sapling Spirits, and every time you buy a bottle of vodka from them, they plant a tree, and on each bottle there’s actually a little code for your tree, and you can go onto the Sapling website and you find your tree in the UK. I mean, talk about conflicting incentives here. Do you want to do “Dry January” or do you want to save the planet? I mean, it’s really hard for somebody trying to make New Year’s resolutions!

And this is the funny thing, I mean about tree planting in general. It’s so difficult to argue with. Trees are aesthetically beautiful objects. They do mitigate the effects of climate change and of urban heat islands.


There was a study that said that if you planted forests on, you know, 0.9 billion hectares of the Earth’s surface, they’d store 205 gigatons of carbon, which is a third of all the carbon that humans have ever released into the atmosphere. So trees make math like this possible. They’re easy to count; they can be scaled.

A woman in Kenya can plant a single tree, or a company in Seattle can pay for a million trees to be planted. I mean, the numbers give us a feeling of control that we’re making a kind of metric progress towards an environmental goal. But of course, those very numbers also appeal to corporations, which can then use them to itemize their green credentials.


And that’s where the shady side, no pun intended, of tree planting comes into view.

Nalis: But if trees are so good at capturing carbon, why don’t we just, like, plant a trillion trees? I mean, I understand that corporations may be doing this for their own gain, but what is the downside here?


Are there downsides to planting more trees?

Samanth: Planting trees can definitely undo some damage that we’ve done to the atmosphere, but there’s no way, you know, a trillion new trees can soak up enough carbon to avert the climate crisis, right? No way. And the damage is that if we see that as a sort of panacea, and companies are only too willing for that to happen, then we get distracted from deeper, more systemic solutions to the crisis. And all of those systemic solutions involve cutting down on fossil fuel use.


The other problem is that large scale tree planting is really likely to compromise biodiversity in the quest to battle climate change. So a monoculture of trees, which is planting one single species across hundreds of hectares, destroys the environment in a different way. There are scientists who study grasslands like the savanna in Africa, for instance. They’re pretty alarmed at how these tree planting advocates want to reforest those very areas, even though they haven’t held forests in practically forever. The species that live in the savanna, not just plants, but birds, animals, insects… they will not necessarily thrive in a forest.

So there’s so much to consider, and I feel like you said that rampant tree planting is really the commission of the same mistake all over again. So we’ve gotten into trouble once already with the climate crisis by underestimating the balance and the complexity of the natural world. And now we’re doing it again by greenlighting the planting of all these trees without really thinking about it enough.


Nalis: I think also to me, philosophically, one thing that is concerning, is that we’ve now turned trees from, like, something that we should respect and take care of into something that serves our purpose.

Samanth: Yeah, I mean it’s a sticking plaster. Much like many other solutions that are proposed to the climate crisis right now are sticking plasters. It’s something that’s quick that’s sort of easy to advertise, that’s easy for the public to understand. Everybody knows what it is to plant a tree. You don’t have to explain it in the same way as you would if you were, for example, a company trying to decarbonize its supply chain. Nobody knows what a supply chain is. I mean, you have to kind of really struggle and read a lot to even envision what a supply chain is and where it stretches and how you might decarbonize it. So, the easy appeal of tree planting makes it a sticking plaster, and that also means a sticking plaster could be ripped off just as easily at any point in the future if anyone chooses to.


Nalis: We touched upon it a little earlier but I was wondering whether there’s any history of marketing this. Like, who kind of came up, if we have any sense, with this idea of packaging it into a very quick solution to companies’ behavior?

The evolution of tree planting

Samanth: Well, I mean, we do know the first instance of a corporate carbon offset in the US. So there was a guy called Roger Sant, who’d founded an energy company in the late 1980s. This was an alternative energy company focused on renewables, but it still had emissions of its own, and he wanted to offset these emissions, so he got in touch with the World Resources Institute and he asked how he could do this. So those guys pointed Sant in the direction of a movement called Mi Cuenca or My Watershed, which was a tree planting drive that had been going on in Guatemala since the 1970s. And so Sant’s company spent 2 million dollars to expand that Guatemala campaign.


It offset around 2 million tons of its own carbon dioxide emissions in the process. And it really gave birth to the concept of the carbon offset that we know today. And this was all, I mean, this was all the late 1980s, you know, this was around the time the American Forestry Association started a campaign with the slogan, “Plant a tree, cool the globe.”

So you can imagine that that’s when companies started to pick up on this idea as well. In 1991, for instance, the Yves Rocher Foundation in France, which made its money from the cosmetics industry, decided it wanted to give back to mankind. And so it started planting trees across France. And the momentum really built in this century, in the 21st century, because the urgency of climate change grew more and more dire. And the pressure built on companies to change their ways.


Nalis: So we’ve established that tree planting may not actually be as helpful as we would like it to be, but are there any actual scammers like, actors who are out there that are exploiting the system to the most?

Samanth: I mean, it feels like stories about replanting scams spill out virtually every month these days. Let me tell you about two specific scam stories, though. The first is about drop ship necklaces from China, and the second is a massive carbon offset scam.


And the first one involved a company called Plant a Tree Company, which was founded in 2019 in the US, and it was active on Instagram for a brief while. So what it did was, it raised money by selling necklaces to plant trees. Yeah. Already weird. But then it turned out it wasn’t even planting trees, you know, in 2019 it posted a photo of some of its volunteers supposedly planting 150 trees in Toronto. Turned out that that was from an older photo shoot about a Canadian whiskey company’s tree planting exercise. So, these guys claim to have planted 6,500 trees in total. In all likelihood, these were probably never planted at all. Or, if they were, we don’t know where they are and we don’t know what their status is.

But then the bigger scams and the bigger companies that profit off of them are the real worry. In January, the Guardian found that more than 90% of the rainforest offset credits approved by Verra, which is a business based in Washington, DC, were largely worthless.


So Verra is a leading standard in carbon offsets. You know, their offsets have been used by Disney, by Shell, by Gucci, by tons of big corporations with plenty of emissions. And they’re behind carbon neutral flights that we take, or the carbon neutral clothes that we wear, or the carbon neutral food that we eat.

The offsets were intended to protect forests from being cut down. But really as the investigation found that threats to those forests were wildly overstated. So, now Verra has disputed all these findings, but we see the problem here, which is this: We consume here in London or New York, and we trust companies to offset there in Madagascar or Cambodia. And as consumers, we are being pushed to accept this “out of sight, out of mind” solution of tree planting. And the companies that push the solution are only too willing to abuse it.


Nalis: Who do you think has the responsibility to make sure that you don’t litter the world with a million horrible necklaces to plant a thousand trees, or you don’t go plant bamboo or eucalyptus where it doesn’t belong?

Who is responsible for managing planting programs?

Samanth: As with so much of the climate crisis, I feel like government agencies and institutions, international institutions, have to almost snatch for themselves the power to regulate this kind of stuff. And it’s happening slowly in other sectors, but it hasn’t really happened that much in tree planting.


I mean, tree planting right now is an entirely voluntary exercise. Companies offer to do it. Consumers offer to pay for it. it’s not part of the law anywhere or in most places. And so, I think it’s impossible to enforce a complete ceasefire, so to speak, on tree planting.

But also it’s not necessarily important to do that. I mean, what is necessary, and I guess what will eventually transpire is some framework of regulation or standards that governs these kinds of tree planting drives that happen in countries around the world. And we haven’t yet come to that stage. I mean, we are approaching in our flawed and fallible ways we are approaching some consensus on standards, but even that falls apart at times. But eventually we will, I hope, arrive at a system of regulation and governance that makes better use of this tree planting energy rather than just let it go unchecked.


But I want to give you, like, the flip side of how the real world regulation scenario is actually quite messy. There’s a law in India that regulates, quote unquote “tree planting,” but it feels like it’s been designed for exploitation and abuse.

So, in the Andaman and Nicobar Islands, which are India’s southernmost territories, there’s a plan to chop down these huge tracts of old forest. And this Indian law says if you’re chopping all of this down, you have to plant an equivalent acreage of forest somewhere else in the country. It can be anywhere. And the absurdity of this is plain. I mean, you won’t get back what you lose if you plant a new forest in the north as compensation for chopping down an old forest in the south. But worse still, the replacement forest for this, this Andaman and Nicobar project, which is coming up in the northern state of Haryana, is already being talked about as a home for a prospective wildlife safari, and entertainment zone. Really nothing like the forest that was decimated at all. So regulation is prone to all sorts of abuse as well, clearly. But you know, more widespread regulation would definitely be a start.


Nalis: But then as an individual, what do I do? I feel like now I’m questioning my own understanding of planting a tree as a good deed!

Samanth: I mean, it’s difficult to say what to do as an individual. I mean, if there’s, like, something that I want to leave our listeners with, something that I wish that they knew, for example, about tree planting. I mean, I wish they knew the things that they aren’t being told. So if they’re paying extra for a carbon-neutral flight, say, I wish the airline was in some sense compelled to reveal where trees are being planted as compensation, what kind of trees are being planted, how they’re being looked after. I mean, I wish people had a way to access reliable audits of these tree planting schemes and reliable scientific assessments of how well designed they are.


But most of all, I wish people knew about the flimsiness of this entire enterprise and that they are being sold this enterprise as a cover for other kinds of actions that companies should take but aren’t taking. And so what I really want people to do is to be able to get into a position to apply pressure on those companies, and they can plant trees on the side as the Parisians did last week. That never hurts, but it’s not sort of the ultimate solution for climate change that it’s being touted as.

Nalis: Thank you so much for sitting with us, Samanth. It was a pleasure and a greatly informative conversation! I feel like I might hold back onto this airline money and maybe try and find a more reliable tree planting initiative independent from corporations.


Samanth: Thank you so much. Pleasure to be here. Nalis.

Nalis: And that’s our obsession, folks.

The Quartz Obsession is a podcast hosted by me, Nalis Merelli, Katie Jane Fernelius is our producer and George Drake mixes and does sound design.


Music is by Taka Yasuzawa and Alex Suguira. Additional production support provided by multi-platform editor extraordinaire, Susan Howson, research wizard Julia Malleck, and audience insight genius Ashley Webster. Shivank Taksali and Diego Lasarte are our natural born sound engineers. Special thanks to our wonderful guest, Quartz global news editor, Samanth Subramanian, champion of tree planting puns.

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