We just published an interview: Hannah Ritchie on why it makes sense to be optimistic about the environment. You can click through for the audio, a full transcript, and related links. Below are the episode summary and some key excerpts.

Episode summary

There’s no money to invest in education elsewhere, so they almost get trapped in the cycle where they don’t get a lot from crop production, but everyone in the family has to work there to just stay afloat. Basically, you get locked in. There’s almost no opportunities externally to go elsewhere.

So one of my core arguments is that if you’re going to address global poverty, you have to increase agricultural productivity in sub-Saharan Africa. There’s almost no way of avoiding that.

- Hannah Ritchie

In today’s episode, host Luisa Rodriguez interviews the head of research at Our World in Data — Hannah Ritchie — on the case for environmental optimism.

They cover:

• Why agricultural productivity in sub-Saharan Africa could be so important, and how much better things could get
• Her new book about how we could be the first generation to build a sustainable planet
• Whether climate change is the most worrying environmental issue
• How we reduced outdoor air pollution
• Why Hannah is worried about the state of biodiversity
• Solutions that address multiple environmental issues at once
• How the world coordinated to address the hole in the ozone layer
• Surprises from Our World in Data’s research
• Psychological challenges that come up in Hannah’s work
• And plenty more

Get this episode by subscribing to our podcast on the world’s most pressing problems and how to solve them: type ‘80,000 Hours’ into your podcasting app. Or read the transcript.

Producer and editor: Keiran Harris
Audio Engineering Lead: Ben Cordell
Technical editing: Milo McGuire and Dominic Armstrong
Additional content editing: Katy Moore and Luisa Rodriguez
Transcriptions: Katy Moore

Highlights

Why agricultural productivity is so low in sub-Saharan Africa

Luisa Rodriguez: How does labour productivity in sub-Saharan Africa compare to other regions?

Hannah Ritchie: So if we use a metric for it as the amount of value you’d get per worker — so the economic value per person working on the farm — the average for sub-Saharan Africa is half of the global average… [and] it’s 50 times lower than you’d get in the UK or the US. If you look at some countries within sub-Saharan Africa, they’re like half of the sub-Saharan Africa average. So there you’re talking about 100 times less than you’d get in the UK or the US.

Hannah Ritchie: So you put that in context: the value that an average farmer in the US might create in three to four days is the same as a Tanzanian farmer for the entire year.

Luisa Rodriguez: Why is it so low in sub-Saharan Africa?

Hannah Ritchie: I think there’s a couple of reasons. One is that the farms are really small, so often the amount of crop or value you get out is quite low. And maybe we’ll come onto crop yields. So with low crop yields, you get not that much out, but also, as you said, you can’t afford machinery, or you can’t afford fertilisers or pesticides, or things that would basically substitute for human power inputs. So it just means you need lots of hands on deck to keep the farm going and keep it at that baseline level of productivity. So you don’t get much out, and you just need lots of people working on the farm.

Luisa Rodriguez: OK, and then the other thing that seems to be really low here is land productivity. Which feels a bit more intuitive to me, is that basically how much crop yield you’d get from, for example, an acre of land?

Hannah Ritchie: Yeah, exactly. So it’s like what most people would call a crop yield. So say we each have a hectare to grow wheat. If you got four tonnes, and I got two tonnes, your land productivity would be twice what I get. It’s just how much you get from a unit of land. There’s a couple of factors that come into it. One is, as you say, the quality of land. So the texture of the soil, the natural nutrient density, carbon content of the soil, how well it drains: all of these affect how well a crop will grow. But there are also ways that we can change some of those aspects. We can use irrigation or drainage to determine how much water is in the soil. Or we can apply our own nutrients for fertilisers. So there’s natural conditions, but there’s also inputs that we can use to change that.

Luisa Rodriguez: Cool. OK, and again, I’m guessing land productivity is much lower in sub-Saharan Africa. How much lower is it relative to other regions?

Hannah Ritchie: Again, it’s very low. One way we can compare is we would use cereal yields, because most regions grow some cereals. So if you compare the average in sub-Saharan Africa, it’s about half that of India, which is less than half of the global average. So it’s pretty poor. And then if you compare that to richer countries, it’s like four to five times lower. But then again, there are countries within sub-Saharan Africa that will get half again of that regional average. So there are some countries where you’re talking about getting 10 times less per unit of land than in rich countries.

The sustainability equation

Luisa Rodriguez: I’ve read the first few chapters of the book and really enjoyed it. Early on, you make the claim that kind of surprised me: that the world has actually never been sustainable. And I just found that really counterintuitive, until I read more about what you meant. Can you explain that?

Hannah Ritchie: Sure. So I get that it’s a controversial claim, and it does seem counterintuitive. I think probably where you came from on that initially, I’m guessing you were thinking about purely environmental sustainability — where you’re thinking about all of the big environmental problems that you face. So the rise in energy consumption and CO2 and plastic pollution, et cetera, has basically happened in the last 200 years or so — most of it probably in the last 50 years. So if you look at those trends, it’s like all this bad stuff has happened in the last 50 years, and before it was all fine, and there were none of these problems. And that’s where I also would have come from, from an environmental background. And I think when you frame it as that, there’s a large amount of truth to the fact that our ancestors were sustainable. They didn’t have really large environmental impacts. I would say that’s mostly true. There are some areas… Like, it’s not the case that they lived in perfect balance with nature.

Luisa Rodriguez: Yeah. It does seem like one of those things that’s really easy to romanticise. Like, Indigenous peoples didn’t cause harm to the environment; they lived harmoniously with it or something.

Hannah Ritchie: Yeah. And there’s clear examples where there just were large impacts. One key one is if you look at the change in biodiversity — specifically mammal biodiversity — over time, you see that mammals have gotten smaller and smaller. This has been happening over millennia; this is not just the last two centuries. And a large part of that was overhunting, and the humans were hunting. And at the time, the populations were really, really small — like, talking about a global population of maybe 5 million at the time — and more than 100 of the world’s largest mammal species went extinct. And most of that is thought to be through overhunting. So it’s not the case that there was zero impact.

I actually accept the argument that, environmentally, our ancestors mostly lived with a very low environmental impact, and recently that’s been knocked off. But where I would contest the sustainability part is, if you think about why their environmental impact was so low, it’s because their populations were tiny. And the reason their populations were tiny is because child mortality was so high. Half of children were dying before reaching puberty, so you had really high fertility rates — lots of children being born, but half of them were dying — so you basically didn’t really have population growth, and populations were tiny. So my contest there is: Is that really what we’re saying sustainability is?

If you care about human suffering, to me, you also need to consider that in this definition we want to adopt of “sustainability.” So I think my definition there is kind of the definition of sustainable development, which is a kind of newish but also controversial term for some people: we need to have low environmental impacts to protect future generations and other species, but we also need to meet the needs of the current generation. Like, we want to have low human suffering today, but also protect future generations and other species.

So to me, the sustainability equation has two halves there. And I think we’ve never achieved both halves at the same time. Our ancestors might have achieved the environmental part, but they didn’t achieve the human suffering part. We’ve kind of flipped the other way, where we’re doing much better on meeting human needs, but it’s come at the cost of the environment. And my core argument in the book is that I think we could be the first generation that does achieve both at the same time, if we do the right things.

How buying environmentally friendly technology in helps low-income countries

Hannah Ritchie: I think the economics and the political ends often go very closely together. I often get the question from people of changing individual behaviours. Like, what impact does it actually have? And am I wasting my time because it’s all about systemic change? Or you hear this argument often from countries, some of them very rich — like the UK, for example, where people say the UK only emits 1% of carbon emissions; what we do just doesn’t matter in the scheme of things. But the key argument I’m making — whether it’s talking about individual changes or changes for countries which now are quite small emitters — is that the impacts they have really have these large spillover impacts on policies, but also on the economics of the technologies.

So an example of that on an individual level is like, one way you can have additional impact is on the signal you’re sending to policies — that you care about the environment, you care about climate change. But there’s also a really strong technology economics signal you’re sending, where if you buy an electric car, you’re showing to the market, “Hey, there’s a big market over here for people to serve. Come and serve us.” Or installing solar power or buying meat substitutes instead: what you’re doing there, as we discussed, we need to make these technologies cheaper for people in low-income countries, for them to have as the default option. And by buying those, you’re basically bringing down the cost curve for all of these technologies. So your impact is way beyond your individual thing. It’s like this collective pulling the market in a certain direction.

Luisa Rodriguez: Right. OK, so the argument is something like, you might not think it’s that important for you to buy an electric car from your own environmental perspective — because generally cars in the UK have technology built in them that means you won’t be emitting loads, even if you have a non-electric car — but if loads of people in the UK buy electric cars, then the electric car technology just gets really good, and drives the price down. And if the price is low enough, other countries, lower- and middle-income countries, might eventually get to just go right to the electric car and skip over some of that intermediate step where they’re polluting loads.

Hannah Ritchie: Right. I mean, I think that wasn’t strictly true, because cars in the UK might have lower local air pollutants, but they still emit a lot of carbon. So it’s not that they don’t have a lot of carbon. But yeah, that’s the core of the argument: that basically what pulled these prices down was people buying them when they were really expensive. And that’s the only reason that they’ve come down in costs, is because they were being deployed because people were buying them when they were expensive. And we never would have seen these costs decline if we hadn’t invested in them early.

Luisa Rodriguez: I guess I had not had the visceral sense that rich people in California all buying Teslas was that important for the world. But I guess if it’s creating this flow-through effect where it makes Teslas and the technology that makes Teslas possible much cheaper, then they will just eventually exist elsewhere in the world much sooner than they might have otherwise.

Hannah Ritchie: Right. I mean, the price decline on these technologies is enormous. For example, if you look at batteries, the big hurdle for electric cars for a long time was the cost of the batteries. So if you go back to 1990, I calculated the cost of a Tesla battery that you’d use in a Tesla car today would have cost like $1 million. And it now costs like $13,000.

So I often when I think about climate action, I’ve been really frustrated by how slow progress has been, and it seems like we’ve not been making progress. But when you think about the cost of these technologies a couple of decades ago, it’s very obvious why weren’t making a lot of progress. Like, no one was buying a car that costs £1 million for the battery. And it’s the same for solar and wind, for example. They were just way too expensive for the world to adopt.

And part of why I’m so optimistic is because all of these technologies are now very cost-competitive. It’s just a completely different situation from where we were even a decade ago, where it just seemed completely unfeasible that the world would pay loads of money to install them. And now it just seems obvious, because they’re actually, in many cases, cheaper. Like, the cost of solar panels has fallen by more than 90% in the last decade. In the last decade.

4 ways to change our food system to solve several environmental issues at once

Luisa Rodriguez: You said that we really need to kind of radically change our food system. I don’t really know what that looks like.

Hannah Ritchie: Yeah, I think it’s probably not as complicated as it seems. There’s just a couple of big, massive, low-hanging fruits. The biggest one is eating less meat and dairy, and there I would say specifically beef.

Hannah Ritchie: [But] reducing meat consumption overall — it’s very obvious to me that we’re not going to switch overnight, and we might just not get rid of meat consumption completely. Like, we might just always have a world where there’s some meat consumption. So I think there’s massive gains there from the meat that we do produce. There’s definitely much better ways of doing that and much more efficient ways of doing it. So there’s low-hanging fruit there in optimising where we produce the meat to reduce the environmental impact.

The third one is increasing crop yields, which just has massive environmental benefits.

And then the final really big one is just reducing food waste and losses. And there’s two components to it. One is what we call food “losses,” which are almost unintentional losses. That often happens between the farm and reaching the consumer or the retail stage — where people don’t want to lose the food because they’re losing money, but it might go off because they can’t afford refrigeration, or it’s damaged in transport. So there’s various reasons why you would unintentionally lose food. And actually, those losses are pretty high.

Policy change doesn't have to be slow

Hannah Ritchie: I think one big lesson [from the ozone story] is just that, as you said, I think we often see these problems as inevitably, they’re going to take a long time, and action just has to be slow. And I think there’s this problem, but also some other specific examples, where change can happen faster if we actually put our minds to it. So I think it’s not inevitable that progress on these has to be slow.

We addressed this relatively quickly. The acid rain story for many countries was also very fast. If you look at China, when China wants to take action, it works very quickly. And I’m not saying that’s a model that other countries can emulate, for various reasons. But there’s just several examples where it’s clear to me that it’s not inevitable that they have to be slow.

I think often politicians or policymakers, for example, can get away with the argument of, “It’s just going to take a long time. These things just take a long time.” But I actually think if you can bring real examples where that’s just not the case, then it’s very hard for them to retreat from that. I always make this argument.

Coming back to earlier, where we were discussing relatively small emitters today and what role they can play in actually addressing climate change. There, I think there’s a very clear example of if a country takes action and almost provides a model that other countries can follow, then it makes a massive impact. And there’s the speed thing. For example, you see Norway: nearly all of the cars sold in Norway today are electric, which is just way ahead of anyone else in the world. And it’s done that very quickly. So no other country can use the excuse that they can’t scale electric vehicles very quickly, because we have examples that it’s happening.

Luisa Rodriguez: I guess Norway is really wealthy. So there will be barriers for many countries to doing that.

Hannah Ritchie: Yeah, for the poorest by far, for sure, that’s the case. But even in China, for example, more than a third of new cars sold in China are electric. I would expect within the next three years, maybe, it’s going to be more than half of new cars sold. It’s moving really quickly. So I think there will be examples.