Long before chemistry was a formal science, humans were experimenting with substances to solve problems, cure illnesses and make money. In his book "The Age of Alchemy: How Early Innovators Shaped Modern Chemistry" (Profile Books, 2026), author Kit Chapman, a science journalist and honorary researcher at Falmouth University in the U.K., traces how this ancient, protoscientific tradition shaped the world.

From our ancestors' early use of fire to some accidental — and disastrous — pyrotechnics in the 14th-century French court of Charles VI, Chapman reveals how early innovations across the world paved the way for modern science.

Live Science spoke with Chapman about his book, which has been short-listed for the 2026 Royal Society Trivedi Science Book Prize.

Read an excerpt: 'These were harder than any other blades, cut sharper and cost more': How ancient Sri Lankans created steel of legends by harnessing monsoons

Hannah Osborne: The book is full of brilliant historical anecdotes that bring all of these alchemy breakthroughs into context. What was your favorite one and why?

Kit Chapman: I mean, you can't go wrong with a man trying to turn his own urine into gold, I think. Hennig Brand [who accidentally discovered phosphorus in the 17th century] was one of my early touchstones. I've known about this story for a while. I've always thought, "How can I get this into a book? What's the link?" Obviously alchemy provides this fantastic base. He bankrupted two wives to try and fund his 1,500-gallon [5,700 liters] urine habit — and then he gets something [phosphorous], against the odds.

This is the first element we can actually put a name to. This is the first person we can say actually discovered a chemical element, and it's an alchemist in the purest sense of the word. Then, of course, he tries to keep it secret. He sells it, eventually, to a friend, and his urine goes on tour around Europe, showing the kings and queens this glowing pee, before suddenly, [chemist and philosopher] Robert Boyle actually works out exactly what's going on.

That, to me, sort of encompassed everything I was hoping for in the book. There's a fantastic story there that's about human connection. There's the unraveling of mythology, and theology and belief, and starting to look at science. But there's also real practical stuff going on there. He didn't know what he was doing. He just didn't know why he was doing it, and that I found fascinating.

HO: You make the point that these people weren't thinking, "Oh, I'm going to do chemistry." How important is that for understanding how these early innovations shaped modern knowledge of how things work?

KC: I think that's essential. We often look at science as something separate from the real world, and one of the things that I really wanted to do with this book was to illustrate that science is going on in every profession. It's going on in every home, continuously; it's going on in our bodies continuously. It's everywhere.

Science is a way to understand what's going on in the world. It is not a separate thing from culture, from belief, from trade, from globalization, from discovery, from just getting on with life. I wanted to bring in the potters, the weavers, the bakers, the urine salesmen — which was an entire thing that I didn't really know I had to go down. I found it fascinating.

And, of course, [there are] artisans. When we start looking at the first actual chemistry that's being done, it is people trying to create beautiful works of art, perfumes, things like that. It moves away from survival and into this ecstatic beauty, and that, to me, encompasses what I love about the history of science. It's bringing all of these threads together and making discoveries not necessarily where we think we're going to find them.

HO: You mentioned the beauty of it all, and the perfume. One of the chapters I really enjoyed was the first chemist who was a female perfume maker in ancient Assyria.

KC: Tappūtī Bēlet-ekallim. The fascinating thing is that the only reason we know her name is that she put it down in cuneiform. She wrote it down. She may well have been a slave; perfume makers were often slaves. She was certainly a woman who was working in the palace. She was working with another woman whose name, unfortunately, we've lost to time.

What I find fascinating is that we now have this person who was one of the working class, one of the underdogs, slaving for a week to make this potion that she wrote down because the recipe is incredibly detailed. And we remember her name, but we have no recollection of the lord or lady that she was actually making it for. It's kind of class warfare throughout the centuries.

HO: I found the extreme sort of secrecy really striking — that so many of these ancient texts were lost because they were being hidden. But then you also have the fall of civilizations, so we've lost all this knowledge.

KC: It's this combination of, as you mentioned, hiding the recipes because they are trade secrets. If you look at the first alchemy book that we actually know of — "Physika Kai Mystika" — it literally translates as "natural and secret questions" or trade secrets. These were craftsmen, and, of course, they didn't want to share it with rival craftsmen. If you've got a really good recipe for making something look like gold, you want to keep that to yourself.

They use these code words — and that went all the way through into what we think of as alchemy, that sort of Renaissance period where they're talking about taking the fiery sword from the belly of the dragon, which is just wonderful and descriptive.

But you also have things like Emperor Diocletian destroying the texts in Alexandria in 300 A.D. Why did he do it? Because it was a matter of survival for him. Twenty-five of his predecessors were murdered by their own guards or died of plague and things like that ‪—‬ horrible fates. He wanted to avoid that, and the idea that [someone] could turn something into gold terrified him. It would debase his currency, so it always brings in that politics. It brings in human nature and human curiosity.

HO: Do you think there are still things we're yet to discover from alchemy from the past?

KC: Yeah, without question. Whether or not we're going to discover some kind of new, groundbreaking technology that's going to change the world, I can't see that happening. But the one thing we could see is the use of natural products in a way that we hadn't necessarily thought [of].

A great example of that is [Nobel Prize-winning chemist] Tu Youyou and the discovery of artemisinin compounds [from the] qinghao [plant], which comes from a Chinese alchemist's herbal remedies book, essentially 1,700 years ago. The fact that the best defense we have against malaria, the best antimalarials possible, comes from this ancient alchemical source indicates that there's probably more to find.

There is almost certainly more to find in terms of how they [ancient alchemists] used recipes, how they would try and make gold. Their understanding of the world is something that we don't necessarily have a full grasp of, and we're still piecing it together. There's some wonderful work being done by Matteo Martinelli and others looking at the history of, particularly of Western alchemy emerging in Egypt.

We also have things like Greek fire. We have a pretty good idea how they did it, but if you're looking for what the exact recipe [is], we're still not 100% sure.

HO: It's interesting now, watching modern equivalents taking place. We still, to an extent, try to guard our own knowledge.

KC: Yeah, we do, and I think it's actually a pernicious thing in science. We have this publish-or -perish mentality, which is that if we don't get the paper out first, obviously we lose the patent, but wider than that, we lose the kudos. There's this kind of necessity to kind of hide things. You hear about all kinds of shenanigans ‪—‬ a reviewer delaying a paper until their paper comes out, things like that, all this kind of naughtiness going on.

We've got to recognize that science has moved on certainly from the "Great Man" idea. We're now working collaboratively in teams. That is the only way that modern science gets done. The second, if there is one lesson from the book, it's that if you try and hide science, you delay progress.

The moment you actually start spreading ideas, the real ignition for me for the Renaissance and for what becomes chemistry, is the printing press. It's the fact that ideas can then be shared and accessed by everybody. The moment we start realizing that science is a global endeavor, that everyone can do it ‪—‬ man, woman, child, it doesn't matter your nationality, [it] doesn't matter your ethnic ethnicity, it's for everybody ‪—‬ the sooner we're going to start seeing some major progress that we otherwise wouldn't make.

HO: We see loads of the advances in chemistry and alchemy within civilizational melting pots. What were some of the biggest surprises to you when you were researching the book?

KC: One thing that really annoyed me was, looking through textbooks, you can look at who made zinc, and you come up with a name that came from the 1700s, or how platinum was discovered — that's a fantastic example. Platinum was discovered by a conquistador who noticed that some natives were wearing platinum. But, of course, he didn't discover it; it was discovered by the Indigenous populations.

The amount of science that came out of Mesoamerica, Central America, and the way that science was also being developed in India, it's just kind of completely overlooked. If you look at the traditional story of science, we talk about Europe. Occasionally, we might bring in China. But India, Africa, Mesoamerica, South America, North America ‪—‬ every single continent was having scientific discoveries and developments.

They weren't necessarily developments that we think of in terms of leading to chemistry, but they were dealing with social problems that they had at the time. They were tackling what was in front of them, and we always need to remember when we're looking at history to look at the context of the discoveries.

HO: Which breakthrough did you think was most impressive in terms of the materials or facilities that were available?

KC: One thing that I found sort of striking was, there's a chap called Paracelsus who is absolutely fascinating, absolutely bonkers. Paracelsus is, for me, the archetypical alchemist because he was certainly trying to revitalize medicine and get rid of humor theory and come up with all these ideas. [Editor's note: Humor theory is the idea that human health and temperament were related to four fluids in the body — black and yellow bile, blood and phlegm.] But he also believed that mermaids were real and that they were just out to steal men's souls.

He was a drunk, he had a broadsword, and yet he's the guy that was able to combine what we think of as the traditional herbalist role and the doctors. At that point, doctors weren't even touching patients. They believed that the true skill of a medical man was that you didn't even need to examine a patient; you could just sort of look at them and you'd know what was wrong. He [Paracelsus] was able to say, "No, that's not right; you need to actually test things, and you need to try things." The moment we actually combine those two different threads together is when we actually started to get what becomes of modern medicine. The number of lives that saves is incalculable, so I think that that's one of the great moments.

The other one that always comes to me is Antoine Lavoisier in the French Revolution. He made several great discoveries — the fact that matter can only be changed; it can't be destroyed [at least at low energies]. The idea that if you take something, then obviously there's got to be components to that; you're not making it out of thin air. And coming up with a list of elements in the French Revolution or just before the French Revolution, unfortunately dies, from the guillotine [when Lavoisier was executed].

That, for me, was when we started to get true chemistry. That's when all of the magic is dispelled. I think he [Lavoisier] is, for me, the French equivalent of Isaac Newton. He's incredible.

HO: For you personally, throughout researching and writing the book, what was your biggest takeaway and what was the biggest surprise?

KC: My biggest takeaway is that science happens everywhere continuously through everyone. I traveled around the world for this book; I went to pretty much all of the continents. I didn't go down to Australia; that's about it. Wherever you go, there are discoveries being made. There are people who are trying to make their worlds better.

Science is not for this elite group; it's for everyone. One of the things I try to do with this book is to show people that even if you think that science isn't for you, it absolutely is; you're doing science continuously.

There've been so many [surprises]. One of the things — this is purely because of the way that I was taught and these inherent biases that we have — but it's so easy to overlook the role of women. When you start delving into the role of women in science … You've mentioned Tappūtī; we also have Mary the Jewess. Throughout the Renaissance, we have people like Caterina Sforza and [the] very famous Queen Christina of Sweden, which I didn't mention in the book because I just didn't have space.

The one shocker for me is this book "The Secrets of Isabella Cortese," which was a man pretending to be a woman to sell his science book. For me, [it] just kind of unravels this whole idea that science isn't for everyone.

This interview has been condensed and edited lightly for clarity.

Climate change's impacts are being felt everywhere, from health and food security to extreme weather, sea level rise and collapsing ecosystems. World leaders have been slow to adapt to the warnings, despite an ever-growing body of evidence showing the compounding risks of greenhouse gas emissions.

But despite fossil fuels remaining the world's primary source of energy and emissions continuing to rise, there are changes afoot.

In his book "Despite it All" (Granta, 2026), author and journalist Fred Pearce looks at the shifts that have taken place over the last 40 years, highlighting how far humanity has come in the green transition. He believes this progress gives us reason to hope that we can eventually overcome the challenges we face today.

Pearce spoke with Live Science about his book, which has been shortlisted for the 2026 Royal Society Trivedi Science Book Prize.

Hannah Osborne: There are a lot of positive environmental stories throughout the book, including those that aren't necessarily being told. Do you think that there is a growing appetite for positive climate news now? And will it help us?

Fred Pearce: I detect a kind of desire to be told something other than it's all hopeless and there's nothing we can do. Some people are therefore saying, "Well, what can I do?" And they're very sort of personal stories about how they can contribute. But also people who think more, if you like, strategically: What can the world do, what can governments do, what, how can we influence that?

I try not to write what I think people want to read. I try to write what I want to say. And it seems to me that we do so many things so badly, whether it's managing our resources or water or handling forests or the climate, or pollution or whatever. We do things so badly that there is a great deal of scope for doing things a lot better. So, we need optimists and we need pessimists. We need pessimists to point out the problems. We need optimists to come up with some solutions or suggest where [there are] half open doors that we can push open.

I wrote this book in that kind of spirit to say "Look, yes, things are bad, yes, I'm not denying that they're bad, but there's an awful lot that we can do about it and in some cases are doing about it." That then divides into whether we're talking about human activity, our technical solutions to climate change. Tech fixes are good, not bad, which is something that can be a hard sell in the environment community sometimes, so I want to stress that.

I went to the Earth Summit 30 years ago where they agreed [upon] the original climate change convention. Back then they said we [need to] prevent dangerous climate change, but they really didn't know much about how to do it. Wind turbines were just, you know, a few masts on a hill in California. Nobody was dealing much in solar power because it was just so expensive. It had been developed for powering satellites and electric cars. Nobody was talking about [it].

We have made quite a lot of progress and it's not fast enough and CO₂ emissions are stable, they're not going down. We need to do a hell of a lot more and we may have passed climate tipping points. I'm not denying any of that, but rather than throwing up our hands or saying it's hopeless, let's get on with the tech, let's also recognize that nature is very good at recovering. You destroy a forest, a rainforest, it doesn't mean that it's destroyed forever. It will, given the chance, come back if we give it room. So let's give forests room to recover.

In large parts of the world it's already happening — in Europe, even in North America. Agricultural land is being abandoned, and when it's abandoned nature comes back and not necessarily in the sort of ways that we might think. But nature does come back, stuff regrows. We can see how evolution is being kickstarted, if you like, by the chaos that we're creating. That's not to say we shouldn't stop creating the chaos, but we can see how nature recovers.

These are things that we can recognize and respond to; giving nature room to recover, rewilding projects, therefore I'm all in favor of [them]. We're not rewilding where we're trying to garden nature to get back to some sort of perfected past, a pristine system where we thought that everything was great — pre-industrial revolution or before Europeans arrived in North America or whatever it might be. But, we can give nature room to evolve and adapt and change. We can see that nature's doing that all the time, with or without climate change and with or without humans. Nature is constantly, if you like, remaking itself.

I'm not saying nature always comes back in ways that we approve of. Let's recognize the distinction between our sort of slightly romanticized idea of what nature should be and what nature actually is.

HO: You talk about rewilding and letting nature take its course, but how do humans fit in with this? Can we adapt our own perceptions of what nature is allowed and what's not?

FP: I think we can probably forget about what's allowed and what's not. Nature will do what it wants to do. We pride ourselves on our ability to garden nature in a way, or manage ecosystems. We're not really very good at it. Nature will very often take over and do what it wants to do.

Some of the world's biggest rewilding projects have gone quite badly wrong because we haven't quite thought it through. The one I'm thinking of really is the large project in the Netherlands where they're trying to sort of recreate ancient European ecosystems and they ended up with mass deaths of animals because their conception of the ecosystem didn't quite figure out. They then largely abandoned the project because they didn't like to see large numbers of animals dying.

A hardline rewilder would say let nature take its course. I see the case for that, and often I would support that, but we have our own sensibilities and our own concerns and we are living in a world where we are very much in charge of what's going on. So while I'm in favor of standing back and letting nature take its course, we have our own sensibilities, and it's not wrong for us to want to intervene sometimes.

HO: There's a chapter on human population and fertility rates, and how this is very much a climate change story as well. We're now seeing a lot of the rhetoric around this, and rights being stripped back and taken away. What's it like for you, having seen the changes from the UN International Conference on Population in Mexico in the 80s, to Cairo in the 90s to now?

FP: It's an extraordinary story. I've been working on these issues for 40 years now so I've seen a number of changes. Some of the changes I've seen are how technical fixes somehow became a reality when they seemed very distant a while ago.

But our perceptions change too on many things. We are, in many ways, more attuned to environmental issues now than we were 30 or 40 years ago. One of the big changes that I've seen is the notion of the population bomb, which for much of the 20th century was seen as the number one issue. People would say, "Well, there's no point in fixing the climate, there's no point in reducing our pollution because there are more and more people on the planet, and we're kind of doomed for that reason."

Well, it hasn't [happened]. When I went to my first international conference, which was the UN Population Conference in Mexico City in 1984, that was all the rage. They gave the UN Population prize to the mastermind of China's one child policy, which — in terms of human rights and what I would regard as acceptable human behavior — was dreadful. But such was the concern about population issues that they wanted to give a prize to the operator of that program.

A lot has changed. A feminist agenda, if I could put it that way, and I would say that approvingly, has taken over in reproductive politics. I saw it at a UN population conference in Cairo in 1994, 10 years after the Mexico event, that we need to assert reproductive rights. Many environmentalists said that's a cop out. It was all "it's feminist perspective, but it's dooming us."

Well, it didn't, because what we found was that by and large, women wanted to have smaller families because their children got to grow up. Medical improvements meant that you didn't have to have four or five children to secure the next generation. Two would usually do, sometimes you just wanted one. Women wanted to have lives outside the home. The population people seemed to be a bit surprised by that.

The environmental agenda was a very male-dominated one for a long time. So that came as a bit of a surprise, but the net result is that we've halved our fertility rates. They're more or less down to replacement levels [of reproduction] now globally.

I'm not just talking about Europe or North America. I'm talking about almost everywhere except Africa, and African levels have come down. Sometimes they're coming down to super low levels, so that people are now talking about not having enough babies and how we can encourage people to have babies. There are parts of the world where we're down to one child per woman and even a bit less.

My argument is that we need to carry on. Not take a sort of Elon Musk approach [or] send the women back to the home and [do] reproduction and that's what their job is. We need to complete the feminist revolution so that women have more rights, can make better choices, and indeed couples can make more and better choices about the family size that they want. We can arrange things so that it is possible to have children and a career, or make it easier to do that, and at that point probably reproduction levels will come back up.

What I'm really saying is that the agenda is now vastly different from what it was as recently as the 1980s and, and into the 1990s. The population bomb is being defused, to put it simply, there's a residual momentum effect which means that our numbers will carry on going up a bit. Sure, that creates strains on the planet, but we're not now talking about double the world population every 30 years, which is what was being talked about back in the mid 20th century. It's tailing off.

We now have, if you like, a consumption bomb more than a population bomb. The global issue is consumption in the rich world, and that's what's stressing the planet now — not too many babies in poor parts of the world.

HO: Inequality between the super rich and people in developing countries is becoming more and more stark. How do we bridge the gap to make sure there's a reasonable living standard for regular people without a huge cost to the environment?

FP: The truth is, and the numbers have been done by a number of different people, a reasonable standard of living for everybody on the planet is perfectly feasible without destroying the planet.

We need to do some things better, we need to have better technology, but for me, right up there with climate change is an issue of global inequality. When I was young, it was taken [that] inequalities were diminishing and it was taken almost as read that they would carry on diminishing, and a lot of aid policies were directed towards that. That's kind of disappeared since the sort of Reaganomics of the 1980s, all the changes in the finance system and perhaps the fall of the Berlin Wall, which meant that the sort of socialist or, or equality-based agendas collapsed politically.

We're now finding increased inequality, and that, it seems to me, is a threat to the lives of millions and billions of humans, but also to global stability and our ability perhaps to manage.

Serious global issues like climate change and many others are all undermined by the political stresses and economic stresses created by rising inequality. I see them going together.

It's also clear that it's important to level up, but also level down from the obscene riches that we see among a small number of individuals, who seem to be accumulating a greater share of the world's wealth, whether we're talking about dollars or natural resources.

HO: You have a whole chapter on renewables and how they're outpacing fossil fuels. They're the cheaper alternative. How do you see the political opposition to clean energy panning out over the next five to 10 years?

FP: It's fizzling out. It's a weird political backlash and yes, any big social trend or economic trend, they all have backlashes and it feels to me like this is it. What we see in the real world is that the U.S. — not just the U.S., but principally the U.S. — are in a state of near denial about climate and they're wanting to go back to fossil fuels.

In the rest of the world, if you look at it in terms of geopolitics of [the] U.S. versus China, then the U.S. is pushing this rather old agenda of fossil fuels, and China is absolutely going to reap the benefits in many, many ways in its drive towards renewables. China has been a really bad story in the past with its coal burning — and it's still building a few coal-fired power stations. But the really big story is how China has been principally responsible for bringing down the costs of renewable energy, particularly solar power.

You can now go to the most remote corners of rural Africa and you find people putting up their solar panels to recharge car batteries so that they can run their lights in the evening or whatever it is. And then you've got megacities operating using increasing amounts of solar power. India is getting on the bandwagon as well. It's got the fastest growing solar energy economy in the world.

In the real world, renewable [energy] is mostly cheaper than fossil fuels. It is also quicker to install, you don't have to build a huge power station, you can do it in bits and pieces, bolt bits on.

Yes, there are grid issues and they need to be addressed, and there are limits on operating. There are challenges, but renewables are just growing so fast, and it is growing so fast because it is so cheap.

And it's become so cheap, to put it very simply, because the Chinese 20 or 30 years ago decided this is what's going to happen. While everybody else was sort of talking about it and fussing about it and doing it in research labs, the Chinese kind of got to grips with it. I remember back in the 1990s talking about people who were going into China and coming back and telling me stories about how the Chinese are really serious about renewable energy. To be honest, I didn't quite believe them, but they were right, and 30 years on, the world is living with the benefits. That's true whether you're talking about Europe or rural Africa or big cities in Asia or wherever. It's coming.

There will be different solutions in different places and there are undoubtedly things that are harder to do than, you know, running our national grids on renewable energy, which is becoming really quite easy and something that everybody wants to do. The cement industries, fertilizers perhaps, some of these industries will take some more technical innovation. But it's happening, these are technical fixes that are working in the real world. Will we do it in time? Well, we're a bit late on the case, but we are on the case.

HO: We're now seeing a massive rise in AI data centers as well. Is this bad tech, shall we say?

FP: It's a serious issue. Partly because they're growing so fast — they can't just plug into the grid because the grid really can't deliver, so these companies are developing their own energy systems. Even in the U.S. they are very often renewable systems because they're cheaper. If you've got a data center out in Texas, then you're going to use wind power or solar power because it's cheaper and you're in control of it.

I suppose we reach a point where [we have to decide], do we want to reduce our use of energy or have almost as much energy as we want, but just green it and green it very fast. It is true that if all the renewable investment is going into electricity for data centers, that leaves less investment for other sectors of the economy, so I'm sure there are trade-offs, and I'm not saying that we should embrace data centers. But they can be a driving force for adoption of different forms of energy, renewable energy, and for perhaps changes in the grid systems as well.

I think we can have both. I think we need to have both because we're probably not going to stop the data engines, so we've got to find ways of greening them. There are issues and there are challenges ahead, and I don't want to diminish any of those, but you know, let's, let's be hopeful.

The title of the book uses the word hopeful rather than optimist because I don't want to sound Panglossian, but I do want to inject some hope.

HO: When you started writing the book, what did you hope people would take from it, and did that change after you'd finished?

FP: Well it kind of evolved. It began as an idea to sort of [be a] retrospective of my reporting, and then the publisher said, "Well, the story changes rather a lot along the way, so rather than just showcasing your reporting over 40 years, why don't you showcase the change, and be hopeful in the context of how things have changed over the last 40 years?"

That was [the] kind of starting point, and we sharpened up on it, as we went along it did become "Despite It All" and you know, the title is important, and not diminishing the "All." There's a lot of bad stuff out there, but despite it all we can have hope and we can find, develop and demand solutions.

HO: Did you find anything during the process of writing the book that surprised you?

FP: As I say, it started as a sort of retrospective project and going through it, [there were places I went years ago] and it did look bad, then I checked up on what had happened over the intervening years and suddenly things looked a lot better.

I went to Alaska and saw how the conflicts over managing caribou herds and the huge migrations that go on and it felt like that was doomed. I was talking to people who were hunting the animals and they were trying to protect them because they wanted to hunt them, therefore they wanted them still to be there, which is kind of counterintuitive for many environmentalists, but you know, they were the best defenders of the caribou because they ate them.

But it felt doomed, and yet 20 years later I checked out the numbers and the population of that herd has doubled and tripled. So stuff does happen and I suppose my surprise was how much good change I found when I looked into it further. Maybe that's me being better at looking for good news stories. I've written quite a lot of "bad news" books over the years and done a lot of "bad news" journalism over the years, so I certainly don't discount that. But if you step back and you think, well did good stuff happen? Well, yeah, sometimes it did.

The bison herds are coming back on the plains of parts of North America, if you go to Montana. The ranches are disappearing and big areas are being set aside for bison, and I've been seeing how farmland in parts of southern and eastern Europe has been abandoned over the years. It's not necessarily good news that we're abandoning farmland, but again, the way that nature comes back and woodlands are growing, there are more forests in Europe than there have been for probably centuries.

There's a lot of bad stuff to say. But it does seem to me that we have to not just cling onto, but embrace good stuff and try [to] take it forward.

Something I really hadn't thought about till I went back was what were the big issues in the 1980s, 1970s when I started out. Well, all our industrial rivers in Britain were filthy. Now our industrial rivers are relatively clean. It's our agricultural rivers that are filthy, so, I mean, there's been a big change there.

Nobody has to talk much about the ozone layer now. That was the number one issue in the mid 1980s, and the absolutely terrifying prospect if we hadn't fixed that. But it's been fixed.

We banned the chemicals that were doing it.

Remember acid rain, lead in petrol. They were hot topics, headline news, part of the rise of the environmental agenda in the 1980s — and they're the ones that we don't have to talk about anymore.

Now we're talking about climate change. I think there are other things coming up. I think the issue of nitrogen pollution is a fast growing one, and we need technical solutions to that.

The green revolution of crops, the high-yielding crops, which got us out of a cycle of ever worsening hunger and famines in the mid 20 century. That was a solution which created new problems. Those crops grew very well, but they required large amounts of inputs, including water, and water is now a growing issue — finding enough irrigation water, but also fertilizer and other agrichemicals. We're now reaping some of the bad effects of that, and we need to solve that. Scientists I know are working on, if you like, high-yielding crops that don't require so much fertilizer and don't require so much water.

It's doable because as I think I said at the start, we do a lot of things really very badly, but that does give us a lot of scope to do things a lot better, so let's get on with it.

This interview has been condensed and edited lightly for clarity.