On the future: An interview with Martin Rees

Martin Rees has been Astronomer Royal since 1995. As a member of the UK’s House of Lords and former President of the Royal Society, he is much involved in international science and issues of technological risk. One of the world’s foremost cosmologists, he has studied the Big Bang, black holes, galaxy formation, and gamma ray bursts. In this interview he discusses his 2018 book On the Future: Prospects for Humanity with Robert McLachlan.

RM: Amongst scientists, cosmologists surely have the most cosmic view of time and space. Has that influenced your view of our present situation?

MR: The main reason that a cosmologist has a distinctive view is that we have an awareness of the far future. Most people, unless they are fundamentalists, are aware of the four billion years of cosmic evolution in the past, but many of them somehow think that we humans are the end of the process, the culmination. I think no astronomer could believe that, because we know that the sun is less than halfway through its life, and the universe may go on forever. So we see the future as being more long term. That makes us even less willing than most people to discount it.

RM: Does that change how you value the present?

MR: Not very much, because the main issue in environmental debates is to get people to think fifty or one hundred years ahead.

RM: It’s been a spectacular few decades in astronomy – it’s always a golden age in astronomy – gravitational waves, extrasolar planets, dark energy. What do you think is the most exciting or significant discovery?

MR: I’ve been lucky to be at the subject for fifty years now. When I started in the late 1960s, it was exciting: the first evidence for the Big Bang, black holes, neutron stars, …

Bob Wilson and Arno Penzias in front of the antenna with which they accidentally discovered the remnant radiation from the Big Bang in 1964.
High resolution map of the cosmic microwave background measured in the 2000s by satellite. These tiny fluctuations, seen much as they were when the Universe was 1/40,000th of its present age, evolved to become galaxies.

RM: That’s right, the cosmic microwave background was only discovered in 1964! So recent!

MR: Yes, an exciting period. And it was a good time for young people like me to join the subject, because when things are happening fast, the experience of the old guys is at a discount and young people can make an impact quickly. But looking at what’s been happening in the last five years, I think those entering the subject now are just as lucky, for all those things you mentioned. The opportunities for new discoveries are higher than ever now.

RM: You’ve worked on supermassive black holes. That must have been pretty special to see an actual photograph of a supermassive black hole.

The Virgo cluster of galaxies, 53 million light years distant. It spans the apparent width of your fist held at arms length. At the lower left is Messier 87, one of the most massive galaxies known, which contains at its core a supermassive black hole, also the most massive known (6 billion solar masses). This was the first black hole to be photographed directly, in April 2019.

MR: That picture didn’t really surprise us very much, because we had indirect evidence of what was there.

RM: Amazing resolution though!

MR: It is an amazing technical achievement what they did, to link together data from telescopes around the world and mesh it together, not in real time but much later.

RM: Turning to your book, “On the future: Prospects for humanity”, you wrote that your theme is optimism and anxiety. You’re trying to balance those two things. It seems to me you must have been influenced by the times, you would have come of age at the most anxious period of the cold war, you’ve seen all these technological improvements…

MR: I think so. One point about the cold war is that most of us weren’t aware of just how dangerous it was. When we read the memoirs of people who were active at the time, it was a very dangerous period, for the northern hemisphere anyway. But what’s made me concerned about the issues I address in my book is that during the last twenty years I’ve had the opportunity, through being president of the Royal Society and a member of the House of Lords, to get up to speed on various other policy questions, and this has made me slightly better informed about some of them, and to worry about some of the implications.

RM [laughs] And how did that tilt the balance between anxiety and optimism?

MR: It makes me a technical optimist, but a political pessimist. The advances in science are very exciting, and already we know enough to provide a good life for everyone on the planet. The fact that we’re not doing that is a political and ethical indictment. I do worry about the environmental effect of a larger global population, all empowered by technology using more resources. It’s very hard to deal with because it does require concerted global action. But I also worry about the misuse of bio and cyber technology. What’s new about those is that they allow a small group, even a single person, to have an impact that could cascade very widely and globally. This is something new. I like to say “the global village will have its village idiots” and they now have a global range. To cope with that, the new challenge is to balance attention between privacy, security, and liberty. For the next ten or twenty years, that’s my main concern. Disruption of that kind is going to be more frequent and is going to weaken the fabric of society. It’s going to be very hard to cope with that, because everyone says, “you have to have regulations”, but enforcing those regulations globally is really as hard as enforcing the drug laws globally or the tax laws globally. It’s not like nuclear, where you have large special-purpose facilities and you can monitor and verify what’s happening. You can’t monitor what’s happening in every biotech lab or everyone who has access to the internet.

RM: You mentioned “consequences”. All of these complex phenomena suffer from cascading consequences.

MR: We’re all connected. You probably know the Jared Diamond book Collapse. The difference with his scenarios is that now if there were collapse in one continent it would go global. That is rather scary.

RM: You mentioned Johan Rockström’s idea of nine Planetary Boundaries, which is a very powerful framework for looking at environmental issues. We’re living at the point where we’re running right up against those boundaries. Wasn’t this inevitable, that given economic growth and expanding power and consumption of resources, we were bound to run into this problem eventually?

MR: The population of course is growing. It’s doubled in the last fifty years. Fortunately, partly due to biotech, food production has kept pace with the rising population, so the doomsters of the late 1960s like Paul Ehrlich and the Club of Rome were overpessimistic. They thought there would be mass starvation by now. Although there is more pressure on world food supplies, that has been met by advanced technology. Famines still occur, but they’re due to maldistribution or conflict, not overall shortage. Even though the population is certain to rise to something like nine billion by mid-century, I don’t think there needs to be extreme pressure on food or resources (although there may well be). Everyone says that economic growth is going to use more and more resources. But economic growth can be of a kind that doesn’t use more raw materials, nor more energy. The most rapid economic growth is in electronics, and apart from pressure on a few rare earths, which is a serious constraint, that doesn’t consume much in the way of resources compared to old-style massive factories.

RM: When I run my eye down these planetary boundaries, many of these problems were not predicted. Ocean acidification was discovered in 2003, the ozone hole in 1985, the instability of the Antarctic ice sheets 1978. Given the power of science, isn’t that surprising? Is it related to unpredictability and tipping points?

MR: These topics were understudied. People didn’t study these issues enough. They only became mainstream science in the last twenty years. One message is that there may be other things that we are not aware of yet which will be just as concerning twenty years from now.

RM: Carbon dioxide dissolving in the sea to form an acid isn’t very complicated science.

MR: It’s consequences are still controversial, the coral reefs in Australia…

RM: Just astonishing. 2500km long and a quarter of the Great Barrier Reef is dead already.

        Speaking of nine billion population, I wanted to read from your book.

“On the other hand, 20 billion could live sustainably with a tolerable, if ascetic quality of life, if they adopted a vegan diet, travelled little, lived in small, high-density apartments, connected by a super internet and virtual reality. This latter scenario is plainly improbable and certainly not alluring.”

        I’m afraid that that is exactly the civilisation that we’re heading towards!

MR: It’s not clear, because in two-thirds of countries, and globally, the birth rate is going down. The reason the population is going to be higher by mid-century is because the demographic transition hasn’t happened in Africa, and secondly, because most people in the world are young, because of the growth in the last fifty years. And they’re going to have longer lifespans. So the prediction is confident to 2050. After that, there are some UN projections in which the growth does continue, but it may be that the population peaks soon after 2050 and starts going down. Surely we would like it to go down. If people are going to have decent lives and enough space, then, even though we can’t define a carrying capacity for the world because it does depend hugely on lifestyle, I think most people would say a less populated world  – 5 billion – would be better, and would give a higher chance of everyone having reasonable space and a reasonable share of resources. That’s what I hope. The biggest concern is what happens in Africa, where the demographic transition hasn’t happened. In rural regions, women are still having seven children. Their population is going to double by 2050. In some scenarios, if the birthrate doesn’t fall, there is another doubling, from 2 billion to 4 billion, by 2100. Nigeria would have a population of 900 million, equal to Europe and North America combined. If, as a consequence, Africa remains in the poverty trap, that’s surely bad news for the world: massive global instability, massive migration. Even though there will be some technical advances, it’s not at all obvious how the inequality between Africa and the more prosperous regions could be reduced. There are two things working against it. One technology that has percolated widely in Africa is IT and mobile phones. That means they are less fatalistic about their fate. They know what they’re missing. They know what it’s like in the rest of the world. This is a recipe for greater embitterment and disaffection.

RM: Which is what we’re seeing now.

MR: Yes, understandably. And the other point is that they don’t have the opportunity that the so-called East Asian Tigers had, to have an economic spurt by undercutting wage costs in manufacturing. Now there’s what’s called re-shoring of manufacturing, with robots doing that sort of work. That means it’s hard to imagine how Africa is going to catch up. I think it’s going to mean that, not just for altruistic reasons, but in our self interest, the prosperous countries ought to subsidize development in Africa. It’s a mega version of what’s been suggested by the Oxford economist Paul Collier, to deal with the Syrian refugees. There are several million of them in Jordan and other places. He points out that they don’t really want to come to England as refugees, they would like to earn a good living in Jordan, with a reasonable hope of going back to their homes sometime. We may need a version of the Marshall Plan to help Africa catch up with the rest of the world.

RM: And there’s another scenario, in which we do rein in population but still struggle with resource use.

MR: Yes, we’ve got to make sure that people are sparing of resources, because the world couldn’t support even three or four billion people if they all lived like middle class Americans or Europeans.

RM: So it almost needs a complete revolution in our attitudes and the way we live. At the moment, as soon as people get richer they want to fly more.

MR: There will have to be constraints. Still, the development of IT will diminish pressure on resources.

RM: Possibly, but that points to your scenario in which we’re living in virtual reality in little box apartments and not valuing what has been lost. The Shifting Baseline phenomenon was pointed out by the fisheries scientist Daniel Pauly: it refers to a failure to notice slow change, and also to a failure to appreciate what has been lost. Once a species has gone extinct, it’s sad, but it’s also too late, it’s out of people’s lives.

MR: I think that’s true. It’s an interesting question to what extent economic advance has actually made us happier and more fulfilled in our lives. We’ve lost as well as gained. One consequence of growth has been greater inequality as the demand for certain kinds of work has gone down. If you look at the lifestyle of the average blue collar worker in Western countries, in many respects it’s got worse: housing costs have gone up faster than their real wages, they’ve got less job security, less status. The only thing which has improved their lives is access to IT. Those are products where there’s a large consumer surplus: what we have to pay is less than we’d be prepared to pay. I’d be prepared to pay more for access to Google than to run my car. 

RM: You go on to talk about this short termism problem. That seems to be extremely fundamental. It’s got a philosophical component – what do we actually owe the future – and a political component: how to actually value the future more.

MR: We have short termism because of politicians worrying about the next election, and that also means their concerns are parochial rather than global. In business, the quarterly company report, and CEOs being incentivized by share options. And because everything is changing so fast, some people use that as an excuse for not planning ahead. “We don’t know what it will be like, so how can we plan?” And that’s true to some extent, because the changes are much faster than they were in earlier centuries. I quote in my book the cathedral builders, who, despite their far more limited horizons in space and time than us, built cathedrals that wouldn’t be finished in their lifetime. The reason they were prepared to do that was partly, despite their constricted horizons, they thought their children and grandchildren would lead lives rather similar to theirs. They would appreciate the finished cathedral. I think we have far less confidence predicting the lifestyle of people fifty years from now.

Then to another point, politicians will think long term, and make the right decision on environmental issues, if they feel the public is behind them. That’s why we should welcome all these campaigns like Extinction Rebellion, and also we should welcome the importance of charismatic figures. There’s a nice quote from the anthropologist Margaret Mead, who said, “It takes only a few determined people to change the world. Indeed nothing else ever has.” And that’s true if you think of slavery, women’s suffrage, civil rights, gay rights. All those things start with a few people. Once there is a sufficient fraction of the public concerned, then politicians will take it on board.

Religions can also make people think long term. I quote in my book the Pope’s encyclical in 2015, which did have a big effect on helping to forge a consensus at the Paris climate conference. He has his billion followers, he had a standing ovation at the UN.

More parochially, in this country, Michael Gove has banned plastic straws. He wouldn’t be doing that had it not been for the influence of our secular Pope, David Attenborough, whose programmes were seen by millions and sensitized people to care about this. It wasn’t on the public agenda at all previously.

RM: Cambridge University certainly seems to have been able to adapt to the present while keeping an eye on the long future.

MR: It’s been around for 800 years! It’s the number one science university in Europe, it should care about these things. That’s why I helped to start the Centre for the Study of Existential Risk, to think about long-term planning and long-term risk.

RM: In the book you talk about the responsibility of academics to speak up.

MR: We have the freedom and the opportunity to do this. But still there are far too few people thinking about catastrophic scenarios. There are lots of people thinking about carcinogens in food, and small risks, but fewer thinking about these big ones. Cambridge has an anarchic and flexible structure where it’s quite easy for bottom-up initiatives to gain traction.

RM: When we think about some difficult issues, say climate change and biodiversity loss, people can get pessimistic and start saying that our whole society is wrong and that we have to “end capitalism” or that democracy is fundamentally ill-suited to dealing with these issues. Can we work within our present system and strengthen our institutions sufficiently to address long-term challenges?

MR: Issues like climate change have to be addressed globally. So we do need more organizations like the World Health Organization or the International Atomic Energy Agency to deal with climate and energy and to verify compliance with pledges made at the Paris conference. We’re not moving in the right direction at the moment.

RM: They need to have power and be trusted.

MR: We need to improve our politics and our democracy. First, we’ve got to depend more on the public sector. To digress, one of the things one worries about is changes in employment caused by automation and AI. The owners of the robots have to be taxed and the money used to provide fulfilling jobs for those who are displaced by the robots. It could be a win-win. The people who are now working in call centres or Amazon warehouses – pretty mind-numbing occupations – could have dignified secure employment as teacher aides or carers. In order to have a society where everyone feels respected and useful, probably there has to be greater redistribution of wealth.

RM: Your book discusses AI in the short and long-term. There’s no consensus about how quickly that’s coming. But we are already having trouble with the stability of the systems that we’ve built, for example with Russian interference in elections. Are we building a system that’s very complicated and also very fragile and difficult to control?

MR: We are. This is like the problem of cyberattacks. We are in an arms race between the attackers and the defenders. They will be AI attacks in the future. It will be a continuing disruptive force. It’s hard to know what to do about that, or about biothreats. It’s going to be ever more difficult to manage. We have to minimize the number of people who have a justifiable grievance against the world. All too many do now, because of the huge inequalities which prevail.

RM: You move on to the cosmic significance of life in the universe. There, we have learned something in the last few decades. We now know that planets of all types are common in the galaxy, and we also know that the galaxy is not full of easily decodable high-power radio signals from other civilisations. 

MR: Yes, and we will soon understand enough about how life began on earth, which biologists don’t understand at present. They understand evolution, but not the transition from complex chemistry to the first metabolising reproducing things we call life. I think that will come within twenty years. That will tell us whether the origin of life is a rare fluke or not. We’ll also know whether these other planets around other stars have biospheres. We’ll be able to analyse their atmospheric spectra and look for the ‘red edge’, a discontinuity in the albedo.

RM: Wouldn’t you be willing to bet that the universe is in fact teeming with life?

MR: We know too little to make an informed bet. I’d be disappointed if we don’t find life. Although it would be a cause for a less cosmic modesty if we are really unique. It’s realistic to hope for some evidence of life in the next twenty or thirty years. 

One challenge would be to find another Earth. Having just celebrated the fiftieth anniversary of the Apollo moon landings, and the famous picture of the Earth from the Moon, an aspiration is that by the centenary of that famous image, which will be 2068, we might have an image, equally iconic, of another Earth, orbiting another star.

Whether there’s intelligent life is another question. I think it’s worth a search. Can we conceive what forms it might take?

RM: Some believe that intelligence has the destiny to spread through the universe.

MR: This is the Fermi paradox. Stephen Webb at the Open University wrote a book with 50 counterarguments to the paradox; in the second edition, 75 counterarguments. They’re all rather weak. It remains an open question. My view is, if we look at what has happened here on Earth, and what might happen, within a few centuries, posthumans, probably electronic, will take over. They’ll be near immortal, they won’t need a planet. I suspect that if we do detect evidence for intelligence, it won’t be a civilisation like ours. Even if there are other Earths that have had an evolutionary past like ours, it’s unlikely that they’d be synchronised. Either they’d be far behind, in which case we’d see no evidence, or they’d be far ahead, in which case what we would detect would be their near-immortal electronic progeny.

Darwinian evolution has favoured two things, intelligence and aggression. These electronic entities, as a consequence of intelligent design instead of evolution, might not have any motives that we could understand. They could be living entirely contemplative lives. 

RM: Your overall conclusion is that we need more science, and that we also need to make wise choices about what we do with the science and which sciences to develop. We need better education. 

MR: All rather platitudinous I’m afraid!

RM: My only criticism is that everything in the book would have been true twenty years ago, but now we are seeing disturbing developments like ‘post-truth’. As a scientist, it’s hard to understand how that can be a thing.

MR: But how fundamental a change is that? Is it just a phase? In the past, people got their information via mass media, which were organised by people who knew what they were doing. Now there is so much information being disseminated on the net, it’s very hard for people to find good information. If you’ve got some medical complaint and you look on the internet you’ve got no way of deciding what is rubbish and what is good advice.

RM: The institutions that we evolved over hundreds of years to ensure some kind of proper knowledge base have been subverted and dissolved.

MR: You’re right, this is one of the down sides of the internet. It’s something we have to cope with. Yet the internet allows benign mass movements to develop fast as well, it’s not all bad news!

RM: And this is just the dawn of the internet. But we always feel like we’re living in the present, we really don’t know what’s around the corner.

MR: That’s true, in most contexts we can’t predict thirty years ahead. In some areas, like climate, we can, and that’s what’s scary. In technology, we can’t: twenty-five years ago a smart phone would have seemed magical. There could be some biological development in the next twenty-five years that we’re not even aware of which could have a similar transformative consequence.

On the other hand, it’s not always true that things change fast. There has to be a political or commercial pressure. Many things go in a sigmoid curve, they go fast and then level off. Just thinking of the 50th anniversary of Apollo, fifty years ago many people thought there’d be footprints on Mars long before today. We know why that hasn’t happened, it would have been exorbitantly expensive and robots have made the case weaker. So that technology has languished. Two other things happened that same year – the first test flight of Concorde, we know what happened to that,  and also the first commercial flight of the jumbo jet, which hasn’t changed hugely in the last fifty years. The previous fifty years went from Alcock and Brown’s transatlantic flight to the jumbo jet. Quite a lot happened! Cars also have changed a lot less in the last fifty years than in the fifty before that. So the question is, will IT and bio continue to develop, or will they get stuck?

One area where I think people are losing enthusiasm is driverless cars. Will I ever have a driverless car so that I can sit in the back and relax, as on the train? People are pessimistic that having driverless cars mixed up with the traffic in London would improve anything. Progress will be slow.

RM: You mentioned Mars. In the book you write that you hope to see humans on Mars this century. What is that? Are you sure you’re not nostalgic for the Apollo era?

Earth photographed by NASA’s Curiosity rover in 2014. Visit Mars in Google Earth.

MR: The practical need is getting less. That’s why I wouldn’t spend any taxpayer’s money on human spaceflight to Mars. NASA and ESA are risk-averse. Look at the shuttle – launched 135 times, two failures, each a big national trauma, whereas a 2% failure rate is entirely acceptable to test pilots and adventurers. My scenario is that if Elon Musk and others want to spend private money, accepting much higher risk, then we should cheer them on, just like we cheer on adventurers who walk across the Antarctic.

RM: Even New Zealand has a private space launch capability now!

MR: And you’ve also got some billionaires who have bought properties in New Zealand to escape the catastrophes.

RM: We do. Martin, thank you for your time today.

One thought on “On the future: An interview with Martin Rees

  1. Congratulations! Do you have a recording of the interview that you can share – podcast perhaps? Cheers,

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