Our latest Freakonomics Radio episode is called “Two (Totally Opposite) Ways to Save the Planet.” (You can subscribe to the podcast at Apple Podcasts, Stitcher, or elsewhere, get the RSS feed, or listen via the media player above.)

The environmentalists say we’re doomed if we don’t drastically reduce consumption. The technologists say that human ingenuity can solve just about any problem. A debate that’s been around for decades has become a shouting match. Is anyone right?

Below is a transcript of the episode, modified for your reading pleasure. For more information on the people and ideas in the episode, see the links at the bottom of this post.

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Charles MANN: At one point I was going to call the book Toblerone For Ten Billion. That was vetoed by my editor, for some reason.

Charles C. Mann is a journalist who writes big books about the history of science. His current interest is:

MANN: The modern environmental movement, which I would argue is the only successful ideology to emerge from the 20th century.

By the middle of the twenty-first century, the global population is expected to reach 10 billion.

MANN: And the question is, are we going to be able to satisfy all their demands for food, water, energy.

Also: Toblerone.

MANN: Because in addition to food and water and the basics, they’re going to want occasional treats.

And there’s one more big concern.

MANN: How are we going to deal with climate change? Those are the big challenges.

The future of food, water, energy, and climate change — big challenges indeed. How will those challenges be met?

MANN: There have been two ways that have been suggested, overarching ways, that represent, if you like, poles on a continuum. And they’ve been fighting with each other for decades.

That fight, and those two worldviews, are the subject of Charles Mann’s latest book, which he wound up calling The Wizard and the Prophet. The prophet sounds the alarm and wants us all to cut back. The wizard urges us to charge forward, confident that technology will solve our problems. Surely you’ve heard these prophets and wizards, speaking to us — and usually speaking past each other.

Al GORE: The next generation would be justified in looking back at us and asking, “What were you thinking? Couldn’t you hear what the scientists were saying? Couldn’t you hear what mother nature was screaming at you?” Nathan MYHRVOLD: The way to have a dramatic message is to say we’re all going to die.

The prophet encourages a return to nature.

Mary ROBINSON: We need to replant and save rainforests.

The wizard finds the prophet’s suggestions naïve.

MYHRVOLD: Well, that argument is so absurd on so many levels that the miracle is that there are people who can say it with a straight face.

The prophet sees grave danger in the immediate future:

ROBINSON: We’re going to be into tipping points. The Arctic is going to go. We’re going to see a sea-level rise that will wipe out islands.

The wizard is more optimistic:

MYHRVOLD: I think that if we put our heads together, we will come up with ways to cope. But that’s no fun compared to saying we’re all going to die next Thursday.

Today on Freakonomics Radio: are you more prophet or wizard? Why? And: is anyone right?

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When Charles Mann was in college, there was a book that showed up on the reading list in several classes.

MANN: Ecology, you know, political science, demography.

So he had the chance to read it several times. It was called The Population Bomb. There was a warning on the cover. “While you are reading these words,” it said, “four people will have died from starvation. Most of them children.”

MANN: And it really hit home, and I thought, oh my gosh. The edition I read, which is the first edition, said there would be massive famines in the 1970’s. Basically, it said we are in deep, deep trouble.

And then, in the 1980’s:

MANN: In the 1980’s, I sort of noticed this hadn’t happened.

So were the famine predictions simply wrong? Or: was the doomsaying a calculated strategy, designed to shrink the Earth’s population before it was too late? Environmentalists were saying humankind was pushing the Earth’s limits; technologists, meanwhile, said those limits were nowhere in sight.

MANN: The world is finite, obviously, and the real question is not whether there are limits, but whether the limits are relevant. At some point, we do run out of planet. But what exactly that limit is and when we’re going to hit it — I think it’s much less well-known than either side says it is. DUBNER: So did you come to feel then that both camps — rather than wizards and prophets, we can call them techno-optimists and environmentalists — do you feel that both camps to some degree intentionally misrepresent their strengths in order to engender support, when in fact the reality — and indeed, most solutions — is probably much more nuanced than that? MANN: I think so. I’m not sure about intentionally, because people get convinced. I think that neither side truly appreciates how much of a leap in the dark jumping into the future is. They’re both overly confident that we know what we’re doing. Take energy for instance. The best solution for the prophets is this whole sort of neighborhood solar thing. But that depends on there being innovations in computer technology and innovations in energy storage, in energy transmission, that simply aren’t here yet. Maybe they can be done, but do we actually know how to do it? No. Similarly, the wizards, they typically imagine very large numbers of next-generation nuclear plants. And they argue, totally rationally and totally correctly, that these have the smallest environmental footprint of any form of energy generation. They’re completely right about this. But I’m not actually seeing that happening. Nobody seems to be building these things. Next-generation nuclear plants have been around for 30 or 40 years, at least on the drawing board, and only a few of them have actually ever been tried. So you wonder, how is that going to happen? Both of these: how is this going to happen?

While wrestling with the best ways to move forward when it comes to energy, food, water, and climate change, Charles Mann found himself looking backward. Specifically, to two men — the wizard and the prophet who make up the title of his new book. Its subtitle is: Two Remarkable Scientists and Their Dueling Visions to Shape Tomorrow’s World.

DUBNER: Let’s start with your prophet, William Vogt. So tell us briefly about him, and why he was the one who qualified to become the prophet in your book. MANN: Well, he is, more than anyone else, the progenitor of the modern environmental movement. And the basic idea of it is one of limits. He called it carrying capacity. And this is that the Earth, the environment — another idea he invented, the environment — is governed by these ecological processes and we transgress them at our peril. And therefore we have to hunker down. We have to put on our cardigan sweaters and turn down the thermostat and eat lower in the food chain and all that sort of stuff. And he put this all together in a book. It’s now forgotten, but it was hugely influential, called Road to Survival. It was published in 1948, and it’s the first modern “we’re all going to hell” book, if you know what I mean. DUBNER: As apocalyptic as his beliefs and predictions were, the title itself connotes at least survival, if not prosperity. Was the road to survival, basically, hope that a lot more people don’t get born and/or a lot of people die, and we have enough to go around, and we get small? MANN: Much of the book is a passionate screed for population control, sometimes written in language that makes you cringe. Another big chunk of the book is about how we should do things in a way that fits better within nature, and that’s things like stop farming within marginal land. It’s paying attention to erosion. It’s not overusing fertilizer. DUBNER: So when you say that his discussion about population growth makes you cringe, was it from a classist perspective, the cringing comes from, or racist — how would you describe it? MANN: I would say yes, both. He was, basically, pretty misanthropic. And it’s hard to avoid noticing that although he was very, very hard on rich, white people and overconsumption and being wasteful and destructive and so forth, that the brunt of the population-reduction stuff he’s talking about are on poor, brown people in other parts of the world. And he sometimes described them in language that is really kind of appalling — he talks about Indians breeding with the irresponsibility of codfish, and so forth. In this he was very much a man of that time, unfortunately. And this is something that environmentalists today should be aware of and think about. Their movement has some pretty deep roots in some pretty bad places.

William Vogt’s work inspired the first best-selling environmental book: Silent Spring, by Rachel Carson. Here’s Carson:

Rachel CARSON : Can anyone believe that it is possible to lay down such a barrage of poisons on the surface of the earth without making it unfit for all life? MANN: And books like The Population Bomb; Al Gore’s first book, Earth in the Balance; The Limits to Growth. All these great environmental classics all stem directly from his work. That’s why I picked him.

William Vogt was born in 1902 on Long Island, New York, back when it was largely bucolic.

MANN: And then it was just engulfed by suburbanization. So he tried to find nature, he ends up in a Brooklyn slum, and is plucked from that and goes to one of those schools they have in New York where the deserving poor are given special education.

He becomes the first college graduate in his family — with a degree in French literature.

MANN: And a degree in French literature was probably as useful in career building then as it is now. And he turned to ornithology. He was a passionate birdwatcher. I should mention that he had polio, as well, and he went all over the place despite finding great difficulty in walking and having canes and braces and having to be hauled around and so forth. He was a gutsy guy. And through a whole series of unlikely circumstances — he ends up becoming the official ornithologist of the Peruvian government on these guano islands off the coast of Peru. And these islands have had seabirds roosting on them for millennia upon millennia. And the seabirds do what they do, which is to eat fish nearby and excrete huge quantities of bird poop. I’m allowed to say that on your podcast? DUBNER: Sure are. Absolutely. MANN: You guys are just, you know, hang loose, right? DUBNER: We’re very pro-poop. MANN: Okay. And this, in the 1850’s, became the origin of today’s hugely important fertilizer industry, these vast heaps of bird poop that were on these islands off the coast of Peru. And they became very important to the Peruvian government. To maintain the supply of poop, you need to maintain the supply of birds. In the 1930’s, the supply of birds started declining, and they brought him in, as he said, “to augment the increment of excrement.” And he spent three years there, and he actually did a remarkable piece of ecological science, a foundational piece. He realized that there is an oscillation of the currents there, it’s called today, El Niño, La Niña. And he argued that when the warm water came in, when the El Niño phase came in, the anchovetas, which were the fish that the birds ate on these islands, swam far out into the Pacific to avoid the warm water. They like cold water. And the birds couldn’t reach them. And this recurring phenomenon put a cap on the number of birds that you could have on these islands. And you could not augment the increment of excrement — that nature set these bounds. And if he did increase the bird supply, it would just mean that things would be worse when the next El Niño came in. And this was this powerful insight for him. This is the way nature worked. And he put it together. And then he made two big steps, which I think are enormously important. One is that he said, this kind of phenomenon, which is called a carrying capacity — means that only so much can be produced because of these natural limits — could be stretched like taffy to cover the entire world. The world can be thought of as a single environment with a single carrying capacity. And the second, he said, is that we’re exceeding it. Or we’re about to exceed it, and that’s going to bring us into trouble. DUBNER: William Vogt predicted, specifically, personally, he predicted famine, which as you write, hasn’t come true. So in the 1940’s, the global famine death rate was about 785 people per 100,000 — so, call 800 per 100,000. It’s now 3 per 100,000. So let me ask you this: as a prophet, do you need to be right? Or is it enough to sound the alarm? Because obviously on that dimension at least, a prediction of famine and population wipeout, Vogt was wildly wrong. MANN: Now, I think there are two responses to it. The first is, “Okay, you’re right, it didn’t happen, but it will happen eventually. We just got the timing wrong.” And the second response, which, to my way of thinking at least, is more nuanced, is, “You’re right, we didn’t get that right, but a lot of the other things they predicted, we did get right.” And that is true. Nitrogen pollution is a huge issue. I mean, about 40 percent of the fertilizer that’s been used didn’t get absorbed by plants, and it got — either went up in the air, where it interferes with the ozone layer, not a good idea, or it becomes nitrous oxide, closer to the ground, in the air, which has caused all kinds of health problems. Or even worse, it goes into the streams, which goes into the rivers, which goes into the ocean, causes these enormous blooms of algae and other aquatic plants. These die, they fall down to the bottom. Microorganisms consume them, it’s sort of an orgy of breakfast, and they metabolize so quickly they suck all the oxygen out of the air and you get these huge dead zones in coastal areas around the world. And you can go on and on. All that stuff, if you point to that, they’re looking better.

At the same time as William Vogt, the prophet, was sounding the alarm on overpopulation and what he saw as the resultant famine, there was another scientist whose discoveries would lead to a dramatic growth of the global population. This is the wizard in Charles Mann’s book; his name: Norman Borlaug.

MANN: He was born in a very poor family in Iowa, poor soil, terrible, hardscrabble farm, worked like a dog. He was determined to get off of that, he really hated it, clearly. He thought his way to do it, because he didn’t think he was very smart, was athletics. To do that, he needed to go to college, which he was able to do, really, thanks to the fact that Henry Ford had invented the cheap tractor. DUBNER: Which let his family free him up from the labor, yes? MANN: Right, freed him up from the labor. And even more important, when you have horses, and oxen and so forth doing the labor for you, you have to grow food for them, and you have to tend to them. And they’re just huge time sinks, and they’re land sinks. And a typical small farmer in those days, about 40 percent of the family’s land was devoted to growing the food for the animals. DUBNER: That was one of my favorite statistics in your book. I mean, it’s one of those things that, the minute you see it, it makes perfect sense. But I never would have imagined it. MANN: Exactly. It’s almost like doubling your land. And of course your land becomes more productive. A tractor is a huge, huge deal. DUBNER: On two dimensions at least, right? In terms of making more available land and, obviously, increasing the pace of the labor. MANN: Right, and making people’s lives better, and also being able to accomplish more, just, — it’s vastly better.

Thanks to that tractor, Borlaug did go to college; he studied forestry and eventually got a Ph.D. in plant pathology and genetics. During World War II, he worked at DuPont, trying to make water-proof ration boxes and mold-proof condom wrappers. Then he got a job with the Rockefeller Foundation, trying to boost the production of wheat in Mexico.

MANN: And the remarkable thing is, he succeeded, despite not knowing Spanish, never having been out of the country, never having bred wheat before, hardly having worked with wheat before. And the wheat genome is terrifically complicated, it’s five times as many genes as there are human genes. And because plants can do weird things that mammals can’t, there’s three copies of each genome in every cell. There’s six different versions of each gene. It’s just a mess. DUBNER: So his breakthrough came about from what you described as shuttle breeding. Can you describe A, why that was unusual, why more people didn’t try that; and B, why it worked? MANN: More people didn’t try it because it was literally written in the textbooks that it wouldn’t work. And the thing is, he was so ignorant — very occasionally, ignorance is good. And what he thought to do was — plant breeding is very slow, because in most places there’s only one crop of wheat that you grow a year. It’s either called winter or spring wheat, and you have to wait an entire year to grow the next. And there had been a dogma that you have to breed the crop in the area in which it’s going to be grown. And he thought, “Wait a minute. What if I grow one crop in the south of Mexico and one crop in the north of Mexico, where it’s warmer? And that way, I can do two a year and make things go twice as fast.” DUBNER: Well, Borlaug found a way through, as you said, grit and luck, and a handful of other things, to make wheat a much, much, much more productive and more flexible crop. And this gave way to what we came to call the Green Revolution, and Borlaug went on to win the Nobel Peace Prize. So talk to me about the consequences of, really, this one man and what he helped produce, good and bad consequences. MANN: Well, the good consequences are really striking. If you look at the data, shortly after the Green Revolution, wheat production in Mexico just soars. It basically quadruples. The same techniques come to the American middle west, and that’s when the American middle west becomes a huge agricultural powerhouse. Our yields just increase enormously. It goes to India and Pakistan. Same thing. Then, the Rockefeller and Ford Foundations are excited by what they’re seeing in wheat, and they set up the International Rice Research Institute outside the Philippines, and they resolve to do the same thing with rice. And yields triple there. And the world just grows enormously more food. And sometime in the 1980’s, for the first time in recorded history, the average person on earth has enough food year-round. And famine — except for famine induced by war — basically ends. It’s a huge moment. And I sort of think this should be taught in all the schools. So that’s the good part, and it’s a huge good part. DUBNER: Okay, so let’s talk about the downsides of the Green Revolution. One of them, you write, is that it essentially fueled income inequality. Land became more valuable. It just created a lot of leverage. On the other hand, the alternative would be that everyone gets to be poor and hungry, other than maybe, warlords and kings, right? So how much credence should we give inequality as a downside of the Green Revolution? MANN: I think you should give quite a bit of credence to it, because when we say, “inequality,” it sort of minimizes the actual experience, just as we are talking about, when a small holder’s farm is able to grow four times as much food, the land becomes four times as much valuable, and it becomes worth stealing. And in countries with very weak institutions, which is unfortunately most of the world, it was stolen, often with the active support of the elites in the government. And huge numbers of people were pushed off the farms and forced into slums, and communities were broken up. DUBNER: And what about the environmental costs of the Green Revolution? MANN: The big environmental costs of this are nitrogen pollution. What we talked about before. DUBNER: So did Borlaug, later in life, acknowledge the costs of the growth that he helped produce? MANN: Kind of. There’s a way that, when you’ve accomplished something, and somebody is carping, that you say, “Well yes, but,” and you acknowledge what they do and then you brush past it. He said, “Wait a minute, the work that we’ve done has saved hundreds of millions of people from starvation. That’s a big deal. And there’s no upside without a downside. So yeah, there’s a downside, but holy cow.” And I think that’s pretty easy to understand. I should tell you that I talked briefly with Borlaug before his death. An article had just come out that was trying to estimate the impact of the Green Revolution, and said that Borlaug and his people, if you looked carefully, had saved 600 million lives. So I put this to him, and he was an exceptionally modest guy, a very personally attractive guy. And he said, “Oh, I think that number is exaggerated, and it was a whole bunch of people, and it wasn’t just me,” and all the things you’d expect him to say. And I said, “Look, suppose that they’re off by an order of magnitude, and you yourself are only responsible for saving 60 million lives. How does that feel?” There’s a long pause. “You know what? It feels pretty good.”

Norman Borlaug died in 2009. But the legacy of his wizardry lives on, in force — not only in the modern-day miracle of global agriculture, but in the belief that science and technology can save lives.

MYHRVOLD: You know, there was no golden age of mankind that was better than today. That’s the first point.

William Vogt died way back in 1968. His legacy also roars on, with countless prophets warning us of the coming dangers.

ROBINSON: How could we be mad enough, cruel enough, insane enough to have a world for our children and grandchildren which will be unlivable? And that is what we’re headed toward at the moment.

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DUBNER: So, you called your book The Wizard and The Prophet, not The Wizard Versus The Prophet. But in some ways, it is asking us as readers to judge the two men and the movements that they helped create against each other. It strikes me a little bit as an unfair fight, in that wizards actually do stuff — they invent things and they push new ideas and systems and products, whereas prophets, it seems at least to me, primarily shake their fist against the sky and urge people to stop doing things. MANN: Well, I failed if I have completely convinced you that the prophets don’t do anything, because I don’t think that’s really true. I think there is certainly a lot of decrying and fist-shaking going on. That’s absolutely right. But they are arguing for, really, a different way of life. And, if you like it, a different kind of technology. So there is this clash, but it really represents a preference for different kinds of technology — which need to be invented and supported — rather than an idea of a technology versus decrying technology. Although you’re absolutely right, there is that overtone.

It’s time now to hear from a modern-day prophet. One with impressive credentials:

ROBINSON: My name is Mary Robinson. I’m president now of the Mary Robinson Foundation: Climate Justice, former president of Ireland, former U.N. High Commissioner for Human Rights. DUBNER: Let’s talk for a moment about what you’ve been doing between the U.N. position and now you’ve just written a book called Climate Justice. I’d love to know about the road in politics that led you to this topic. ROBINSON: Well, in a way I’m quite late coming to the importance of climate change in undermining and negating human rights. When I finished my seven years as president of Ireland in 1997, I became high commissioner for human rights. I don’t remember making any significant speech because another part of the U.N. was dealing with climate change. It was when I started work in Africa on behalf of a small N.G.O. and everywhere I went in Africa people kept saying, “things are so much worse.” And it was the unpredictability of the weather. People didn’t know when to sow and then their harvest would be destroyed, and the rainy seasons wouldn’t come. And I realized, my goodness, I missed this. This is a huge issue of human rights, and it’s so unjust, so unfair, and that’s why I don’t talk about climate change. I talk about climate justice. DUBNER: You argue that our environmental problems are at heart human-rights injustices, largely committed by big rich countries like the U.S. against small and poor countries. And that’s an argument I’m sure resonates for many, many people. On the other hand, the technology and resources from rich countries also have a lot of benefits — food production, just to take one. How do you find the middle ground to have conversations that are not so accusatory toward the big, rich, polluting countries? ROBINSON: I think that “climate justice” finds a very good balance in this, because we do acknowledge the injustice of the fact that the emissions have been caused, historically particularly, by the richer countries and now also by the emerging, the Chinas and the Indias and Russias, etc. And that has a big negative impact on food security, on life security, on health, on so many things for poorer developing countries who are not responsible for the emissions. But we also say that we want — when we move to this renewable-energy world, which would be so much better for health, for jobs, etc. — that there is a fairness in ensuring that the poorer countries, and particularly the poorer people in those poorer countries, get the benefit. We need to get to those one billion people who never switch the switch for electricity. We’ve now got off-grid solutions. We need to get to the women, in particular, who cook on open fires with animal dung, coal, wood and ingest and die in very large numbers from that inhalation, and we need to make this an engagement of people in solidarity with other people. DUBNER: It’s a really interesting — not a conflict, quite, you raise, but a two-headed problem, I guess. Technologists — and I guess you could include economists in there — they often advocate for a different set of solutions to problems, whether it’s famine or pollution or so on, than environmentalists do. And I think it mirrors political partisanship, whereby there’s very little middle ground and very little collaboration. Trying to convert people who are using animal dung as fuel — obviously that would require a technological solution that may require more energy from the grid. So can you talk about the two camps — if we consider it truly to be two camps, let’s say environmentalists on one side and real technologists on the other — what are some ways to accomplish a middle ground that you’ve seen in action, that you think are scalable? ROBINSON: I’m not so sure, as you put the issue that way, that we have the kind of middle ground you’re talking about. We have to get out of coal rapidly, period. We have to get out of oil and gas pretty quickly, and be out of all three by 2050 to have that safe world. And what is happening and, I have to say this quite unequivocally, the fossil-fuel world is using the tactics of the tobacco industry. It’s using these tactics to muddy the science, delay things, and deny that there is a real problem. And unfortunately, as we know, President Trump has put in quite a number of climate deniers. How do we understand that the new economy is the renewable energy economy? Solar and wind are becoming so much cheaper. They’re very competitive, far more competitive than coal. We need to have that shift. DUBNER: So you’re calling for the global community, however that can be created or defined, to come together to carry out climate justice. Talk to me about what you see as big previous successes in the global community coming together to solve problems. ROBINSON: Well, one example is when we knew there was a threat to the ozone layer, we came together with the Montreal Convention to make sure that what was causing that problem with the ozone would be completely banned. We need to have exactly the same attitude to climate change. I mean, it has been said, and said very eloquently, we’re the first generation to really understand the dangers of climate change and that’s why we have the Paris commitment to stay well below 2 degrees of warming and work for 1.5 degrees and be carbon neutral by 2050, meaning out of greenhouse gases: coal, oil, gas, etc. And we’re the first generation to understand all of this and the last generation with time and opportunity to make sure we do get out of it. We’re going to be into tipping points. The Arctic is going to go. We’re going to see a sea-level rise that will wipe out the islands. How could we be mad enough, cruel enough, insane enough to have a world for our children and grandchildren which would be unlivable? And that is what we’re headed toward at the moment. MYHRVOLD: The way to have a dramatic message is to say we’re all going to die.

That’s Nathan Myhrvold, the former chief technology officer of Microsoft and now C.E.O. of an invention-and-technology firm called Intellectual Ventures.

MYHRVOLD: If you said, “Oh my God, the changes in the food system mean we’re all going to die,” is a lot worse than saying, “Changes in the food system mean we’re all going to be at least five pounds heavier than we would ideally like to be.” I mean, you don’t get any oomph out of that. DUBNER: If you had to declare yourself, let’s say, x percent wizard and y percent prophet, with “prophet” representing environmentalist and concerned about population and the environment, and “wizard” representing technology and maybe techno-optimist, what are those numbers for you, Nathan Myhrvold? MYHRVOLD: Oh, probably 90-10. And if you push me it might be 98-2. The part where I would differ from many environmentalists is I understand that technology is not just a bad thing that got us in this terrible situation. Technology is also our salvation. And the notion that we have caused problems in our society which we have to fix, in least in part through technology, that is the story of mankind. DUBNER: So, The Economist has said that you have “an unshakeable belief that human ingenuity will sort everything out.” What’s that belief based on? Other than history? MYHRVOLD: Well, historical experience. What do you mean, “other than history?” Our species has faced many, many great challenges. And when we face a great challenge, one of the things that we fall back on is technology. And frankly, that is what distinguishes us from other creatures. Most animals have to undergo biological evolution. They can’t learn and undergo a cultural evolution. When we went from being hunters and gatherers to being agriculturalists, that wasn’t because we evolved new kinds of limbs meant for agriculture. What it meant was we learned how to sow crops and harvest them and build a civilization that could stay in one place because we had a regular food supply. Every time we have a really powerful technology that really changes the world, well of course there’s problems that come up. And you can blame technology, but I think the constant in that equation is humans. So, of course we will over-exploit things, of course we will do a set of things that is very much human nature, but for most problems, we wind up realizing it eventually and we fix it. DUBNER: But a prophet might say, “Well, just because technology or technologies were the solution to one set of problems doesn’t mean it will be the solution to the next set of problems.” And, indeed, if one makes the argument, as many prophets do, that these problems are actually the result of technologies, then, indeed, the most natural solution would be the opposite of that, which is some kind of reversion, some kind of return to a more natural state, a smaller population. So what do you say to that argument? MYHRVOLD: Well, that argument is so absurd on so many levels that the miracle is that there are people who can say it with a straight face. There was no golden age of mankind that was better than today. That’s the first point. There’s a lot of, “Oh, let’s hearken back to those wonderful old days. You know, when the feudal lord oppressed us, when the number-one killer of women was childbirth, when infant mortality was 50 percent.” Oh yeah, I really want those days back. In order to worship the past, you have to have a very bizarre filter on to filter out those aspects of the past that you don’t like. Look, the single biggest thing that would help world population is to get a higher standard of living in the parts of the world where it’s still crushingly bad. If the bottom two billion people in the world had a better lifestyle, ironically, that’s what would lower their population and help them have a better lifestyle going forward.

This is a point on which Myhrvold and Mary Robinson, wizard and prophet, happen to agree.

ROBINSON: We know exactly what will reduce population. It’s educating girls and women, and it’s having a health system that works — universal access to good health care. And we’ve seen in countries all over the world that the population comes down very rapidly when you educate girls and women and have a health system that functions.

On the issue of carbon emissions and climate change, meanwhile? Not much agreement between wizard and prophet there.

MYHRVOLD: I am not saying that global warming is a solved problem, I think is an incredibly hard problem to solve. So, I’m not saying all of our problems are trivial. Far from it. I think that if we put our heads together we will come up with ways to cope and maybe eliminate. And that is a really important thing.

Myhrvold has spent some time thinking about technological solutions to the climate-change problem.

MYHRVOLD: So, climate change is a 1-percent effect. Now all we have to do is make the sun 1 percent dimmer. Now I don’t literally mean changing the sun. But there are a variety of things that bounce sunlight back into space. Clouds are one of those things: white clouds bounce white light back up into space. It turns out that volcanoes throw ash and particles, if it’s a big volcano, very high in the atmosphere. That reflects some of that light. And in fact this happened in 1991 when Mount Pinatubo went off. It cooled worldwide temperatures by a degree, degree-and-a-half-Fahrenheit for 12 to 18 months. Well, my company has come up with some very practical and cost-effective ways of deliberately putting particles into the upper atmosphere. And on paper, it works out that you could nullify all of global warming that way.

These geoengineering ideas are, in many quarters, quite poorly received.

MYHRVOLD: People get extreme, some people anyway, get extremely angry, and they say, “Oh, technology got us in this problem, why are using technology to get us out?” And that’s where I come to think of saying, “Well, okay so are you sincere about worrying about global warming? Or are you using global warming as a stalking horse for your political agenda?” If you’re sincere about the harm of global warming, you say, “I don’t want my environment screwed up. I don’t want millions of people to die.” So, if you take that problem-oriented view, if we can stop that problem, that’s good right?

This is one characteristic of the wizard’s solution: a large-scale, top-down fix. Many prophets, meanwhile, think about small-scale, bottom-up.

ROBINSON: Well there’s a lovely story of this woman that I was very impressed by. She’s an anthropologist. Mrs. Tong, she was a professor who moved from Vietnam to Australia and could have had a very good living in Sydney, and came back to her country because she wanted to work with poor people in her region. She introduced me to the regional officer, she introduced me to the elders, she introduced me to the women, etc. They had broken down the level at which women could be involved comfortably. She said, “If we did it at the district level, women would feel disempowered.” So we broke down to eight families coming together and forming a co-operative, and we now have a number of co-operatives who are in charge of a certain part of the forestry to maintain that forest. And the regional officer, at her persuasion, had given them the right to the fruits of the forest as they say. The first fruits were medicinal and actual fruits. And then they said, “Next year, we’ll be able to cull some of the trees, but we will plant new trees. We will maintain the forest.” And this for me was a wonderful example, which I know is happening in indigenous communities all around the world. They actually save forests. And if we’d only listen to indigenous peoples, we would save far more forests. And we need to replant and save rainforests, and if we listen to those who really understand their neighborhood and their forests, we’ll do it much more quickly and more effectively. DUBNER: A lot of the solutions that you praise and suggest that we scale up are reliant, to some degree at least, on behavior change, on people deciding to make a different kind of consumption decision or whatnot. And as most of us know, even if just from our own personal experience — whether it’s a diet or exercise or spending/saving money, and so on — behavior change and self-discipline can be very difficult. And I’m curious whether you truly believe that relying on humans to “do the right thing” on a large scale will be successful enough to have the kind of effect in the climate realm that you hope for. ROBINSON: Well, I certainly think it is important that we change our behavior to a significant extent, and it is happening. People are recycling more. More young people are vegetarian or even vegan. There is a real acknowledgement that we need to do this, and actually women, in the home and in their community, are more likely to be leaders on changing behavior. That’s what we’re good at in the family. You may not always be successful, and I’m not the best myself. I’m more vegetarian than I was, but I’m not pure vegetarian, yet. I aspire to be. I love some West Ireland lamb, that sort of thing. But the point really is that we need to understand the health and the economic benefits that come from a change in vision about where we want to see the world, and that’s the most important thing. MYHRVOLD: I am skeptical that we will solve it by just doing the right thing. And I mean that somewhat facetiously. To give an example, there was a little book that was popular a few years ago called 50 Simple Things You Can Do to Save the Earth. Well, those are 50 simple things that you can do to feel self-righteous and none of them are going to save the world. And I think that approach, and that attitude, fundamentally mistakes what the problem is, and it creates a situation where people can feel good about themselves. “Oh, I unplugged my iPhone charger while I was away today.” And yet, no matter, even if all of us did that, it would not materially change what’s going to happen to global warming. We have to make actually very painful cuts, which our society isn’t very good at doing. ROBINSON: We need to be careful about how we will move rapidly to having renewable energy in developing countries. Developing countries have become very ambitious to get renewable energy. We’re learning that there are human-rights abuses occurring where clean energy is being put into a country in the wrong way. And the wrong way tends to be mega projects that don’t have any concern for land rights or water rights or indigenous people’s rights to consent locally. An example that I’m aware of was a big wind farm in Kenya, and it was on pastoral land belonging to Maasai pastoralists. Nobody thought they had land rights, but they had always brought their animals on this land. And these big, 365 wind turbines were being built, and they wouldn’t have even benefited from the energy, from the clean energy, the electricity. So they took a case in court in Kenya and blocked the whole thing until their rights were being properly recognized. MYHRVOLD: Well, then there’s nuclear power. So, nuclear power is a carbon-free energy source that absolutely works. The United States got scared of nuclear starting in the 1970’s and through the 1990’s. Then-Vice President Gore presided over the announcement of killing the last nuclear plant in the United States because we were going to build safe coal plants. Now we realize, inconveniently, that global warming is a threat. ROBINSON: Well, I’m not an expert on the nuclear issue, I have to admit that. The way I see it, nuclear energy has its own problems. We saw that in Japan when the nuclear power plants were flooded. What incredible problems, and they’re lifelong problems for the Japanese. There are problems at the end of the lifecycle that make it very expensive. There are problems in building nuclear power stations that make it very expensive. And meanwhile we have the much cheaper renewable energy coming on stream, and that I understand much better. So I’m not making a whole statement. I think it’s true that nuclear power does not produce greenhouse gas emissions and that’s important. France has nuclear energy and has benefited from it but also has the problems now of aging nuclear power stations and the cost to the economy of getting rid of those.

I went back to Charles Mann, author of The Wizard and the Prophet, about the nuclear-power conundrum.

DUBNER: Nuclear power is one of these things that a lot of environmentalists have come around to embrace as — MANN: At least, some. DUBNER: — and what’s interesting is that I look to that as an example of how the standoff between the wizards and the prophets can turn into inertia. Because if there had seen more collaboration and less grandstanding, rather than inventing a technology that then got old and got exported to Japan and France, we probably would have kept building a better technology that by now would be — whether universally accepted or not, who knows — but it seems that the environmentalist protest against nuclear was so strong that it really stymied invention or innovation. So that strikes me as one of the potentially worst paths of having wizards and prophets, or technologists and environmentalists, not sharing a language, sharing a middle ground. And I’m curious where you see this can go, or should go. MANN: Well, the present that we have, as you say, I think quite accurately is the worst of the many worlds, right, in which people are at loggerheads. I suspect that one of the underlying issues is that much of these discussions, the debates, the arguments, are couched in, I think what the philosophers call “prudential terms.” So the people who don’t like nuclear power say, “Well, we don’t like it because it’s unsafe. We don’t like it because of the waste. We don’t like it because of proliferation and so forth.” And those are all true. But they’re mainly pretexts. They don’t like it because they don’t like the path that takes you down, which they see as giant centralized facilities under state control, and further and further away from democracy. They don’t like it for the same reason they just don’t like big corporations. The fundamental arguments are really about values. And we typically argue them on the basis of practical things, as if that is actually what is fueling the debate. I’ve never seen, to my knowledge, a nuclear power person saying, “What if we built compact nukes with smaller scale and shorter life spans that can be used as a bridge fuel in the way that people talk about natural gas?” and say, “Okay, we’ll have this nuclear power plant for 30 years and that will buy us time so that the renewable stuff can kick in.” DUBNER: Why do you think that conversation isn’t happening? Is that a failure of one camp, or is it this construct that has been set up by people like William Vogt, and maybe by Borlaug as well, that we can’t escape? MANN: Well, there is a tendency for people to get really entrenched in their own walls. Our society is now so large that even advocacy groups have become an industry of their own. They have to protect their credibility and they start acting like the corporations that they decry. And it becomes more and more difficult for, not even it’s just a middle ground, but a creativity, to happen. And I think some of that is just a consequence of scale. DUBNER: Let me ask you one last question, I want to know what you think is the prophet’s view and the wizard’s view on colonizing Mars. Right? So I can see that appealing, maybe not equally, but quite robustly to each camp. Obviously it requires a great deal of technology, but for the prophets it’s a chance to start anew with a planet we haven’t screwed up yet. MANN: It’s interesting. I should say that I am — and ever, since I was a child, have been a space enthusiast. I think the kind of tradeoff there is — do you know the science-fiction writer Kim Stanley Robinson’s Mars Trilogy? DUBNER: No. MANN: It’s a fascinating look at exactly colonizing Mars, and, in a certain way it’s all about the clash between the wizards and the prophets, because it’s about how we should live on this new planet. And yes, we need all kinds of technological development. But what is the life that we’re going to have here? And also, how are we going to terraform it? How are we going to make it more habitable? And I think there’s a rich room for disagreement and argument there. You could put it inside a dome city, which would in a certain way be the most efficient way, or else you could really take the challenge of trying to transform the whole planet and make it breathable. DUBNER: If you were going to bring one science adviser with you on that establishment of a human colony there, would it be William Vogt, or would it be Norman Borlaug? MANN: Well, I hadn’t thought about this. What I’m thinking is, which person would I like to be locked up with a small vessel for several years? And Borlaug, I think had a better sense of humor. DUBNER: Yeah, that seems an easy answer. But forget about being locked up. So let’s say that personal confinement was not the one metric that you had to choose your scientist on, but would you rather have the guy who figured out a new dimension of botany? Or a guy who understood that resources are finite and carrying capacity is a concept that should be applied to the environment, and so on? MANN: You know, it’s funny. I think I would choose Vogt. And here’s the reason: that is a hostile environment. Mistakes will kill you. I’m starting out. I want somebody who’s hyper-aware of potential mistakes. I think I would probably have a chance of coming up with some of the innovations and so forth, I’d really want somebody who would point out how I might be on a path to killing myself. So if I could have Borlaug on the way over and transform him to Vogt when I’m there.

Charles Mann’s book is called The Wizard and the Prophet: Two Remarkable Scientists and Their Dueling Visions to Shape Tomorrow’s World. Thanks to him, and also to Mary Robinson and Nathan Myhrvold.

Freakonomics Radio is produced by Stitcher and Dubner Productions. This episode was produced by Harry Huggins. Our staff also includes Alison Craiglow, Greg Rosalsky, Greg Rippin, Alvin Melathe, Zack Lapinski, and Andy Meisenheimer. The music you hear throughout the episode was composed by Luis Guerra. You can subscribe to Freakonomics Radio on Apple Podcasts, Stitcher, or wherever you get your podcasts.