PUBLIC LECTURE
Challenges for the next 50 years
Thursday 25 March 2010
Martin Rees is Professor of Cosmology and Astrophysics and Master of Trinity College at the University of Cambridge and President of the Royal Society. He holds the honorary title of Astronomer Royal. After studying at the University of Cambridge, he held postdoctoral positions in the UK and USA, before becoming a professor at Sussex University. In 1973, he became a fellow of King's College and Plumian Professor of Astronomy and Experimental Philosophy at Cambridge (continuing in the latter post until 1991) and served for ten years as director of Cambridge's Institute of Astronomy. From 1992 to 2003 he was a Royal Society Research Professor.
He is a foreign associate of the National Academy of Sciences, the American Philosophical Society, and the American Academy of Arts and Sciences, and is an honorary member of the Russian Academy of Sciences, the Pontifical Academy, and several other foreign academies. His awards include the Balzan International Prize, the Bower Award for Science of the Franklin Institute, the Cosmology Prize of the Peter Gruber Foundation, and the Crafoord Prize of the Royal Swedish Academy. He is currently on the Board of Trustees of the National Museum of Science and Industry, the Institute for Public Policy Research and the Princeton Institute for Advanced Study, and has served on many bodies connected with education, space research, arms control and international collaboration in science. In 2005 he was appointed to the House of Lords.
He is the author or coauthor of more than 500 research papers, mainly on astrophysics and cosmology, as well as seven books (five for general readership), and numerous magazine and newspaper articles on scientific and general subjects. He has broadcast and lectured widely and held various visiting professorships.
Challenges for the next 50 years
I have given myself a rather ambitious title – ‘Challenges for the next 50 years’ – and I should say at the start that I am not an astrologer, I have no crystal ball and you should not take my forecasts with too much confidence. But I do want to focus on the question of how science can be applied to address the global problems which we are surely going to confront in the next 50 years.
The past record of scientific forecasters is rather dismal: Lord Rutherford averred that nuclear energy was moonshine; the chief executive of a major computer company said in 1975 that nobody would ever need a computer in their home; and one of my predecessors as Astronomer Royal famously said that space travel was utter bilge – and so I won’t add to this inglorious rollcall. In fact, in science, the most transformational advances are the hardest to predict, and that has always been so. Francis Bacon, the great inspirer of the Royal Society 400 years ago, realised this and he adduced gun powder, silk and the mariner’s compass – all Chinese inventions, of course – as examples of big leaps forward that could not have been predicted. And our lives today are moulded by three technologies which gestated in the 1950s but whose pervasive impact could not have then been foreseen. It was in 1958 that Kilby and Noyce built the first integrated circuit, the precursor of today’s ubiquitous silicon chips, and this was perhaps the most transformative single invention of the past century. It has led to consumer items like mobile phones that would have been seen as magic back then. These technologies advance apace, contributing to human welfare in both the developing and the developed world in ways that are less demanding of energy and resources than most that contribute to economic growth and, therefore, are especially benign. In the same decade, the 1950s, Watson and Crick discovered the bedrock mechanism of heredity: the famous double helix. This launched the science in molecular biology, opening up exciting prospects in genomics and synthetic biology, whose main impact still lies ahead.
And to the third technology, space, which is closer to my own scientific interests. It is just over 50 years since the launch of Sputnik. This event, of course, led President Kennedy to launch the Apollo program in response, which eventually led to men landing on the moon. Kennedy’s prime motive was, of course, superpower rivalry. Cynics could deride it as a stunt, but it is an extraordinary achievement when we look back at this, more than 40 years ago. You have to be middle-aged to remember when men last walked on the moon. Indeed, young people today learn that the Egyptians built the pyramids and the Americans landed men on the moon, and these both seem rather strange events motivated by bizarre national goals. But this enterprise had an inspirational aspect too: the distant images of Earth, with its delicate biosphere of clouds, land and oceans contrasting with the sterile moonscape in the foreground, have been iconic ever since the 1960s for environmentalists.
There was no real follow-on after Apollo. There is no practical or scientific motive adequate to justify the huge expense of NASA-style manned space flight and it has lost its glamour. Indeed, the case for sending people into space is getting weaker with every advance in robotics and miniaturisation. Nonetheless, I hope that one day people will walk on Mars, but they will have to go in the mode of explorers and adventurers – accepting much high risk and maybe a oneway ticket, in my opinion. But, of course, there has always been a dark side to space technology. The initial motivation for rocketry was to provide missiles to carry nuclear weapons, and those weapons were themselves the outcome of a huge enterprise: the Manhattan Project – even more intense and focused than the Apollo program. And the nuclear age inaugurated a new era, what some have called the Anthropocene era, the first in our planet’s entire history where one species – ours – could determine, for good or ill, the entire Earth’s future.
There are other concerns, perhaps less dramatic than nuclear war, which are threatening to the planet and these are going to be the theme of part of my talk. Despite the uncertainty of forecasting, there is one fairly confident prediction that we can make: barring catastrophe, there will be a lot more people on the Earth by mid-century than there are today. Fifty years ago, the world’s population was below 3 billion and by the turn of the millennium, it was 6.1 billion; it is now about 6.8 billion and is projected to reach about 9 billion by 2050. By then the world’s physical and intellectual capital will be concentrated in Asia and the Pacific Rim, not in Europe or the US. There’s going to be a tremendous shift of world power.
In most countries fertility has now fallen below replacement level. The average woman has less than one female child, and we all know the demographic and social trends that lead to that: declining infant mortality, availability of contraceptive advice, women’s education and so forth. The transition has been quite sudden and many countries with high fertility have now made the transition. Indeed, one of the most remarkable is Iran, where over 30 years it has dropped from 6.5 children per mother to just over two – and this has already happened in most countries. If the transition quickly extended to all countries, then the global population, though destined to rise until 2050 – as most people now alive are young – would then start to decline, and that might surely be benign.
But one problem is that the demographic transition has not yet occurred in Africa, where there could be a billion more people by 2050 than there are today. In 1950, Europe had nearly three times Africa’s population; in 2050, Africa will have nearly three times Europe’s population. There has been a big relative shift there. And it is in Africa that most of the world’s bottom billion, financially, are concentrated, those living on less than one dollar a day – Paul Collier’s ‘bottom billion’ – and many of them are still trapped in poverty. It is good news that in this context the US administration has now reversed the Bush administration’s constraints on supporting family planning initiatives in Africa. Today’s population could not be fed by yesterday’s agriculture and perhaps a second green revolution will be needed to feed tomorrow’s population – to grow enough food, despite water shortages. Failure to achieve this would be a tragedy of continental proportions, especially in Africa.
The challenge of feeding a growing population is aggravated by climate change – and now a word about that, because a second firm prediction is that the world will be warmer by mid-century. The consequent shifts in weather patterns and eventual rising sea levels impact most grievously on those countries least able to adapt and places that in themselves have contributed minimally to CO2 emissions.
The consensus on the science underlying climate change has, I think, gradually firmed up. There are fewer deniers and fewer day-after-tomorrow doomsters. But there is still controversy. There is particular controversy about the climate over the last 50 years – how much it has warmed or not. For those who are interested in that subject, if you look on the internet you get a whole lot of conflicting views. But I think you should bear in mind what you would do if you had some sort of illness. You might look on the internet and find all kinds of views – not all of uniform quality – but, if you were prudent, you would look at the credentials of the doctor whom you finally went to. I think, similarly, even though you see a tremendous diversity of views on the internet, one should look into the credentials and take more seriously the views of those who have credentials in the subjects and among them you will find a greater consensus.
But, even if there is controversy about how much warming has happened up until now, I think that that is only secondary to the most important fact which is relevant to climate change, which is the carbon dioxide concentration. The measurements of carbon dioxide concentration in the atmosphere – the measurements are straightforward and entirely uncontroversial – are going up. In the measurements made in Hawaii over the last 50 years you see a gradual trend upwards and you also see an annual up and down. That is because there are more trees in the northern hemisphere than in the southern hemisphere and, when the leaves fall off those trees, that increases the carbon dioxide; that’s the oscillation. So there’s no doubt that this is a reliable measurement and the carbon dioxide is rising. And this rise is also known to be due to the burning of fossil fuels. It has also been known since back in the 1850s, with the work of Sir John Tindal, that carbon dioxide is a greenhouse gas: it absorbs in the infrared; it is transparent to visible light; and the more of it there is, the warmer the planet will get. That is the qualitative statement.
Carbon dioxide levels over the last 60,000 years have been in a fairly narrow range. It is predicted that, if we go on burning fossil fuels at the projected rate with no conversion to other sources of energy, it will reach double the preindustrial concentration of carbon dioxide by mid-century and possibly three times by the end. This is something which is going to lead to a temperature rise; by just how much is, of course, uncertain. The IPCC’s first volume from its fourth report has a projection of a whole lot of models. The rise is between 1°C and 5°C, depending on the details of the model.
Incidentally, in discussions on climate change people talk about a temperature rise of 2°C, 3°C or 4°C. That may not seem very much, but that figure is just an index for what are actually large-scale changes in global weather patterns. The climate models that correspond to a 4°C rise in mean temperature give rise to a 10°C rise in parts of Africa. So 4°C may not seem very much, but it is a lot in some areas. In the depth of an ice age, the mean global temperature was only 5°C lower than it is today.
So that is the science. There are big uncertainties in just how sensitive the carbon dioxide concentration induced warming is and that is the big uncertainty in the IPCC results. But the science, I think, is already certain enough to justify precautionary action, although we need more detailed models obviously.
But the science, although intricate, is really a doddle compared to the politics and economics of climate change, and that is for two reasons. First, unlike more familiar kinds of pollution, the effects of CO2 emissions in one part of the world are not just local but go into the general atmosphere; therefore, for any action to be effective, it has to be global and not just local – the benefits do not accrue locally for any local cutback. The second feature of global warming is the time lag. The effects of enhanced carbon dioxide are often delayed by decades: it takes decades for the oceans to come to a new equilibrium et cetera. This is a problem politically, of course, because the ‘urgent’ always trumps the ‘important’, and that is the second reason why it is very hard to get any consensus on climate change action. The Stern report, produced for the British government three years ago, argued that all developed nations should commit substantial resources now to pre-empt much greater costs in future decades and that equity to future generations renders a commercial discount rate quite inappropriate. There has been a lot of debate about the economics, which is genuine debate even if you accept the science.
There are, of course, precedents for longterm altruism in public policy. For instance, in discussing the disposal of nuclear waste, experts talk with a straight face about what might happen more than 10,000 years from now, thereby implying a zero discount rate. That might seem to be a bit over the top in worrying about a post-human era, as it were, but I think history will judge us harshly if we discount too heavily what might happen when our grandchildren grow old. We are mindful of the heritage that we owe to centuries past and should surely plan at least a century ahead.
Well, it is still uncertain, as I said, just how sensitive the climate is to the CO2 level and what parts of the world will be affected most, but what should make us especially anxious is the significant probability of a really drastic climatic shift triggering a grave and irreversible global trend: rising sea levels due to the melting Greenland icecap, runaway release of methane in the tundra and so forth. The target espoused by the G8 was to reduce global carbon emissions by a factor of two by 2050, because it was thought that that is what is needed to keep the global temperature rise below about 2°C. Cutting the global CO2 emissions by half is quite demanding because it would correspond to 2 tonnes of CO2 per year from every person on the planet, or half a tonne of carbon – because carbon is about a quarter of the mass of CO2. In contrast to that figure, Americans are now emitting 20 tonnes of CO2 per year or 5 tonnes of carbon, Europe and Australia about 10 tonnes, China about 5 tonnes and India about 1.5 tonnes. To meet this target, everyone has to converge on two. That is the nature of the challenge.
It is a huge challenge to achieve this global target without stifling economic growth in the developing world. It is therefore urgent to develop cleaner and more efficient technologies soon enough that the Asian per capita emissions never need to rise to ours and that ours go down to converge towards theirs. We get part of the way with present technology. Indeed, most countries can actually cut their emissions substantially and save money by, for instance, insulating buildings better.
But, if we are really to achieve the cuts of 80 per cent – which are needed in a country like Australia or Britain if we are to meet the 2050 target – present technology is not enough; we need more R&D in energy. And I think R&D in energy needs to be funded on the same scale as R&D in health and medicine; it is still far, far lower worldwide. In fact, Tom Friedman in his recent book says that the American energy utilities are spending less on R&D than the American pet food industry is – and that is really not good enough. Indeed, I cannot think of anything that could do more to attract the brightest and best into science than a strongly proclaimed goal by all developed countries to provide clean energy for the entire world. In the US, President Obama has taken a big step forward; he has appointed a dream team of science advisers and declared that energy R&D should have the same national priority as the Apollo program had in the US in the 1960s.
What are the clean energy options? Well, carbon capture and storage is important because coal-fired power stations – China is building 100 of them a year – have a lifetime of 30 years and, if they spew out carbon dioxide for that whole period, it will be very hard to meet these targets. The only way to cut back in less than 30 years would involve carbon capture and storage, which is a technique where surely R&D and the developing of demonstration plants are necessary, even though we cannot be yet quite sure how well it will work. Other technologies depend on which country you are in. In the UK, I think we could take a lead in wave and tidal energy; we have the geography and also the marine technology from the North Sea oil and gas. I was in New Zealand earlier this week, where geothermal is important; and it is different here again. What about biofuels? There has rightly been ambivalence about first-generation biofuels but, in the long run, genetic technology may have a lot to offer. Another general need is for improved energy storage: lithium batteries and super capacitors for transport to smooth over peaks and troughs in demand and to complement unsteady power sources, such as sun and wind.
What is the role of nuclear power in all of this? Again I think it depends on what country you are in. In the UK, I would favour having a replacement generation of power stations and boosted R&D into fourth generation reactors. But the non-proliferation regime is fragile and, before being relaxed about a worldwide program of nuclear power, one would surely require the kind of fuel bank and leasing arrangements that have been proposed by the International Atomic Energy Agency and to make sure they can be enforced. And nuclear fusion deserves to remain an important area of research that could work in the long term. For Europe, my favourite bet would be large solar collectors in the Sahara, spread around Europe by a DC grid – and that is a realistic possibility.
Incidentally, some pessimists argue that the international community will never meet these carbon reduction targets and, therefore, as a fall-back, we should contemplate a kind of ‘Plan B’: being fatalistic about the rise in CO2, but intervening to combat its warming effects by, for instance, putting aerosols in the upper atmosphere and even vast sunshades in space. Well, some of these ideas are not completely crazy and they could be done, but they have problems because they would commit the world to keeping these going. Also there are other effects of rising CO2, like ocean acidification, which they would do nothing to ameliorate.
There is a different kind of geoengineering: direct extraction of CO2 from the atmosphere – a macro version of the sort of scrubbing technologies used in submarines. If that ever became feasible, it might be more politically acceptable; but that is a long way downstream. The Royal Society, in fact, published a report a few months ago on geoengineering, emphasising that it will not solve the problem of climate change. However, I would expect that geoengineering will be higher on the agenda towards 2050 if we don’t achieve cuts in CO2, although it would be another issue for international disputes of contention if we did not agree on how we wanted to change the climate.
Some years ago, I wrote a book which I called Our Final Century? The publishers left out the question mark. Then the American publishers changed the title to Our Final Hour – Americans want instant gratification and, I guess, the reverse. That book addressed some of the issues I have just discussed, emphasising that this is the first century when one species can determine the planet’s future. But there are other concerns. Human activities are severely ravaging the biosphere by rapid changes in land use and deforestation. There have been five great extinctions in the geological past and we are causing a sixth. The extinction rate is about a thousand times higher than the average and it is increasing. We are, as it were, destroying the ‘book of life’ before we have read it. Biodiversity, which is manifested in forests, coral reefs and all Earth’s other ecosystems, is often proclaimed as a crucial component of human wellbeing and economic growth, and it manifestly is. But, for environmentalists, these instrumental and anthropocentric arguments are not the only compelling ones. For them, preserving the richness of our biosphere has value in its own right over and above what it means for us humans.
Overall, our lives are getting safer and healthier. We fret unduly about some risks – carcinogens in food, a one in a million chance of being killed in a train crash and so forth – but we are in denial about others that should loom much larger. I have talked about some collective risks that we face, but there are others. For instance, infectious diseases are a growing hazard. I am not an expert on this, but certainly it is on the cards that a global pandemic could kill many millions of people and cost trillions of dollars. If we apply to pandemics the same prudent analysis that leads us to buy insurance, multiplying probability by consequence, then we would surely conclude that measures to alleviate this kind of extreme event need a higher priority. In the case of pandemics, effective prevention and early warning have to be a fully international endeavour because whether or not a pandemic gets a global grip may hinge on how quickly a Vietnamese poultry farmer, for instance, can diagnose or report any strange sickness. In the coming decades there will be a kind of arms race between ever-improving preventative measures and the growing virulence of the pathogens that could plague us, the latter augmented by risks of bioterror or bioerror. The spread of epidemics is, of course, aggravated by rapid air travel plus the huge concentration of people in mega cities with fragile infrastructures.
And in our ever more interconnected world, there are new concerns. We are all precariously dependent on elaborate networks – electricity grids, air traffic control, the internet, just in time delivery and so forth – and it’s crucial to optimise the resilience of all such systems because, in the future era of vast individual empowerment by biocyber and nanotechnology, even one malign act could be one too many. And we’re kidding ourselves if we think that technical expertise is always allied with balanced rationality; it can be combined with fanaticism – not just the traditional fundamentalism that we’re so mindful of today but New Age irrationalities too. I’m thinking of the Raelians, extreme ecofreaks, violent animal rights campaigners and the like; the global village will have its village idiots. Overall our world may now be safer, but something has changed in the kinds of risk we should worry about. The old risks were localised. If a boiler explodes – and many did in the early days of steam – it’s horrible. But, in our much more interconnected world, there are new risks which consequently could be so widespread that even a tiny probability is disquieting. So these low-probability high-consequence risks, I think, will loom larger on the political agenda.
Let me now inject some optimism, some good news. Obviously, healthcare is improving at a global level; indeed, there has been a welcome rebalancing of effort. Traditionally, the focus was on diseases of the rich – cancer and cardiovascular disease – but tropical diseases are now receiving much more attention, and that is thanks substantially to the Bill and Melinda Gates Foundation. Mindful of where Bill Gates’s money has come from, let’s recall the silicon chip, which has allowed miniaturisation and spawned the worldwide reach of mobile phones, promoting economic growth while being sparing of energy and resources. Mobile phones in Africa have already made a tremendous impact.
Another safe prediction technologically is that computer networks will become ever more powerful and pervasive. Each mobile phone today has far more computer power than NASA had for the entire Apollo program. If advances continue at the same pace, computers may by 2050 achieve human capabilities. Of course, in some respects, they already have – long ago. The most basic pocket calculator can do arithmetic better than we can, and IBM’s Deep Blue computer beat Kasparov, the world chess champion, back in the 1990s. But not even the most advanced robot can yet recognise and move the pieces on a real chess board as adeptly as a five-year-old child. There is a long way to go before interactive human-level robotic intelligence is achieved; but, when that happens, everyone’s lifestyle and work patterns will surely be transformed. There will be interesting ethical issues. If robots become intelligent, do we have to give them the same respect as we would to intelligent animals? Do we care about exploiting them? Should we be concerned if they are bored or unemployed et cetera? There will be entirely new issues like that.
And, for scientists, some kind of mental prosthetics provided by powerful computers may be essential if we are to crack some of the big scientific challenges: a unified theory of physics, understanding consciousness et cetera. These things might be beyond the powers of unaided human brains, just as surely as quantum theory is beyond a chimpanzee. Indeed, as a digression, there is no reason to believe that our brains, which evolved to cope with life on the savannah a few hundred thousand years ago, should be matched to understand the deepest aspects of reality. It is rather remarkable that we have got so far with our brains, which have not changed significantly in the last 100,000 years.
Another speculation in the next 50 years – and the real wild card in population projections – is that a human life span could be greatly extended. Some extension is very likely, but some people believe in a really substantial extension. Indeed, there are some Americans who are worried that they will die before this Nirvana is reached and they bequeath their bodies to be frozen on their death, hoping that some future generations will resurrect them or download their brains into a computer. The cut-price version is to have just your head frozen; that is a lot cheaper. But, for my part, I would still opt to end my days in an English churchyard and not a Californian refrigerator.
But flaky futurologists are not always wrong – I tell my students that they will derive more stimulus from first-rate science fiction than from second-rate science – and we should keep our minds open or at least ajar to concepts on the fringe of science fiction. In this century, novel mind-enhancing drugs, genetics and cyborg techniques may start to alter human beings themselves; the post-human era may beckon sooner than we think.
But, coming back on to firmer ground, I would make one generic forecast that is important to the public and politicians: there will surely be an ever-widening gulf between what science enables us to do and what applications it is prudent or ethical to pursue. There will be more doors that science could open but which are best left closed. Opinion polls show that there is anxiety that science may run away faster than we can properly cope with it. Nonetheless, these polls show a positive attitude towards scientists. They are among the most trusted professionals – up there with doctors, the clergy and teachers and way above bankers, car salesmen, journalists and even, I am afraid, some politicians. But scientists, to maintain their esteem, have an obligation to engage with policymakers and ensure that decisions are based on the best scientific advice. As President Obama acknowledged, scientific advice should be heeded – and I quote – ‘even when it is inconvenient; indeed, especially when it is inconvenient’.
But the decisions that politicians have to take – whether about energy, gene technology, stem cells, mind-enhancing drugs or whatever – are never solely scientific; strategic economic, social and ethical ramifications enter as well, and here scientists must accept that they have no special credentials. Everyone deserves a voice on issues like should we build nuclear power stations or windmills; should the law allow designer babies; how much should computers take over our lives; and what is the right trade-off between surveillance and privacy? But, for public debate on these questions to get above the level of tabloid slogans, citizens all need at least a feel for science and a realistic attitude to risk – and that is not an unrealistic aim. Science seems forbidding because of its technicalities and jargon, and specialists need to master those; but it is the key ideas and not the details that matter for everyone else. I believe that these can – if scientists make the effort to communicate well – be made accessible to everyone. In terms of public engagement, in regard to genetics work in the UK, we have had good and bad examples. Ongoing dialogue with parliamentarians led to a fairly good framework on embryo and stem cell research in the UK; on the other hand, the genetically modified crops debate went wrong in the UK because scientists came in too late, when the prime minister was already polarised between eco-campaigners on the one side and commercial interests on the other. We in the UK – in the Royal Society, in particular – have tried to do better on nanotechnology by raising the key issues upstream of any legislation or commercial development.
I would like to conclude by speaking not just as a worried member of the human race but as a scientist and to assert that there is another reason why we need wide public education in science – not simply because citizens need it but also because science is part of our culture. Indeed, science is the only truly universal culture. Protons, proteins and Pythagoras are the same from China to Peru. All races throughout human history have gazed up at the same night sky and wondered at it, and it is an intellectual impoverishment not to appreciate the panorama offered by modern cosmology and Darwinism – the chain of emerging complexity leading from some mysterious beginning to atoms, stars, planets and biospheres, and brains able to ponder the mystery of it all. This common vision should transcend all differences of nationality and faith and give us all a cosmic perspective.
It is sometimes wrongly imagined that professional cosmologists like me must be serenely unconcerned about next year, next week and tomorrow, but I would like to conclude with a cosmic perspective which actually strengthens my own concern about the here and now. Ever since Darwin, we have been familiar with the stupendous time spans of the evolutionary past – it is nearly 4 billion years from the first life to us – but most people still somehow think we humans are necessarily the culmination of the evolutionary tree. No astronomer could believe that. Even Darwin didn’t believe that; he’s quoted as saying, ‘Not one living species will transmit its unaltered likeness to a distant futurity.’ He believed in future evolution. We now know that our sun is less than halfway through its life: it has been going for 4½ billion years and will keep going for another 6 billion – and that is just our sun. The expanding universe will continue perhaps forever – and, as Woody Allen said, ‘Eternity is very long, especially towards the end.’
And it will not be humans who witness the sun’s demise 6 billion years hence; it will be entities as different from us as we are from a bug. But, even in this concertinaed time line extending millions of centuries into the future as well as into the past, this century is very special: it is, as I said before, the first when one species has the future in its hands and could jeopardise not only itself but life’s immense future potential.
Suppose that some alien should be watching our planet from afar for its entire history; what would they have seen? Over nearly all of that immense time – 4½ billion years – Earth’s appearance would have altered very gradually: the continents drifted; the ice cover waxed and waned; and successive species emerged, evolved and became extinct. But, in just a tiny sliver of the Earth’s history – the last one millionth part, a few thousand years – the patterns of vegetation altered much faster than before. This signalled the beginning of agriculture, and the pace of change accelerated as human populations rose. Then there were other changes, even faster. Within 50 years – little more than one-hundredth of one-millionth of the Earth’s age – the carbon dioxide in the atmosphere began to rise enormously fast and the planet became an intense emitter of radio waves, the total output from all TVs, cell phones and radar transmissions. And something else unprecedented happened: small projectiles launched from the planet’s surface escaped the biosphere completely: some went into orbit around the Earth and some went to the moon and planets. If they understood astrophysics, the aliens could confidently predict that our biosphere would face doom in a few billion years when the sun flares up and dies. But could they have predicted this unprecedented fever, this spike, less than halfway through the Earth’s life – these human-induced alterations occupying, overall, less than a millionth of the elapsed lifetime and seemingly occurring with runaway speed? If they continue to keep watch, what might these hypothetical aliens witness in the next hundred years: will a final spasm be followed by silence or will the planet itself stabilise and will some of the objects launched from Earth spawn new oases of life elsewhere? Well, the choice depends on us and wise choices will require the idealistic and effective efforts of natural scientists, environmentalists, social scientists and humanists, all guided by the knowledge that 21st century science can offer.
Discussion
Question: Thanks very much for your address. I was wondering whether you are aware of your predecessor’s – Lord Florey, Howard Florey, the inventor of penicillin – interest in population growth issues. I think one of his initiatives as president of the Royal Society was to establish a population study group and yet it is something that seems to be glossed over in almost every biography I have read of Florey’s, where the medical profession sort of seems to relegate it to a minor interest. I am just wondering how that kind of interest can be rekindled, because it is such an important topic.
Lord Martin Rees: Well, I fully agree, and I would like to say that the Royal Society is at the moment embarking on a study of the world’s carrying capacity – and, of course, that depends on the lifestyle of people. It is clear that the world cannot handle more than 1 billion people if they all live like present-day Americans; whereas, if on the other hand we all just ate nothing but rice and stayed at home watching virtual reality, it may be 20 billion. So one has to consider the carrying capacity in different contexts. But I think you are right: it is an under discussed topic. The collective academies of the world had a meeting in New Delhi in 1993 where they addressed this topic, and I think it is now time to readdress it and that is why the Royal Society is doing this. I think, of course, the subject has a slightly bad reputation because of Mrs Gandhi and also the Chinese onechild policy. But, nonetheless, it seems to me that, if you talk about places like Africa, there are allegedly 200 million women who do not have access to contraceptive advice; to empower them is surely something which noone, except hardcore Vatican people, can be against. So the case for doing that is certainly very, very strong. That is an investment which would not only improve human welfare but also probably do far more to effect the post-2050 population than anything else we could do. So I share your view: it is understudied. We in the Royal Society are hoping to do a survey of the issue.
Question: Thank you very much for that fascinating address. I would like to ask a question about carbon capture and sequestration. As you pointed out, chlorophyll has been doing this for the past 3.7 billion years and humans have been busy, through agriculture and so on, clearing it, and at the moment there is a pandemic of forest clearing for biofuels or grazing, which seems to be highly unethical. Do you think that more attention should be paid in the political and economic scheme of things to persuade nations to stop clearing forests, not only because they biosequester carbon but also because they contain so much biodiversity and, perhaps most important of all, they provide wonderment for humans to see nature as it was during their evolutionary past?
Lord Martin Rees: I strongly resonate with that for some of the reasons I have mentioned. I mean, clearly preserving biodiversity for its own sake and also the effect on carbon dioxide et cetera – for all those reasons, we should. That, as you say, is a problem with the biofuels of the present time – that they are perhaps not the best use of land. Carbon sequestration of the kind that happens in a power station is a different matter. The problem there is, first, the cost, but also the issue of finding suitable places to deposit the carbon dioxide underground. I think that is going to be what makes it difficult perhaps to implement this on the necessary scale. But, as you say, nature does this.
Question: What would your advice be to a room full of scientists on how we can assist, in our research and as individuals in the next 50 years, to address the sorts of questions you have raised this evening?
Lord Martin Rees: Well, I think scientists obviously should pursue what they are good at; it is a challenging matter and they need to devote their lives to it in order to be effective. But, of course, it is important that they should communicate the results of their work to politicians and to the public, and that is so that the public can be informed and the politicians can have the best advice. But also I would say that it is an extra satisfaction. I work in an area of rather academic science – cosmology and astrophysics – and I would derive far less satisfaction if I could only talk about it to a few fellow specialists. I find it a bonus that there is wide public interest in the general ideas and I believe that one can convey the general ideas to people who do not have the technical expertise to understand the details. That is even more important, of course, when the science is something which is directly relevant to human health.
But I think we also have to emphasise the uncertainties of science, and some of the things that ought to be simple are very hard. I can talk with confidence about a galaxy a billion light years away, which might seem rather arcane; on the other hand, I think we all know that you should not take very seriously anything you are told by an expert on diet or child care. That is not because the people who work in those subjects are incompetent; it is because it’s much harder to do any human science than to understand the inanimate world. So things like diet and child care are very difficult topics. I think the problem for the public is to have a feel for which areas of science are those where scientists can speak very confidently and which areas of science are those where they should suspend judgement.
Question: How does the potential for people to live much longer affect overpopulation? Won’t it be skewing the population to much more elderly people, with the declining number of youngsters coming through with the decline in birth rate? That seems a bit strange to me – that, if people are living longer, the population is not going to be coming down very quickly.
Lord Martin Rees: Well, obviously, even with the birth rate at the replacement level, if the lifetime is extending, the number of people living at any one time is going to go up. But, of course, the social consequences depend crucially on whether there is an extension in active lifetime as well as in overall lifetime. This is an issue which is confronting all of us now. Already people are living to their eighties and the idea of getting a pension from the age of 60 seems completely anomalous in a way that it did not in the past. So obviously, if lifetimes are now extended, that means that working lifetimes have to be extended.
Question: I was very encouraged by your comments about the increasing degree of consensus around the fundamentals of climate science but would comment that that is not the way that the public debate is going, at least in certain places and at least in recent months, as a lot of attention or airtime is being given to a very few individuals with some rather non-mainstream views. I wonder if you could comment on, first of all, why that is happening; and, secondly, if you have any advice for those of us who are trying to communicate the science of climate change and also the urgency of action on climate change.
Lord Martin Rees: Well, I think the controversy is focused on the past history of climate over the last hundred years; I think that is less clear-cut and more complicated than the future projections. That is why in my talk I said that the key fact, in my opinion, is the rise in carbon dioxide. If we knew just that plus simple physics, it would be reason for precautionary action. The past climate and the degree to which climate change has already manifested itself is a more complicated situation, and that is where the focus of the debate is.
But I think the other way to answer your question is to say that the media obviously like a good debate. There were many other areas in the UK – there was the MMR vaccine episode – where you would get one person against a consensus view, and the media always make it appear that there are two sides with equal credentials. I think that is the kind of thing that is happening. Again, as I said in my talk, if you look on the internet, you get a huge range of views on any subject, which implies that everything is controversial. What one has to do really is to focus on the views of those who have genuine credentials. But I think there is a problem because naturally for the media there is greater interest in a good row, as it were, and making everything seem controversial, even when the arguments and the balance of expertise are very unequal.
Question: A lot of questionable decisions on climate change have been made by politicians around the world recently and you have said that more scientists should talk to politicians; but you, yourself, are a member of the House of Lords. Rather than talking to politicians, shouldn’t more people like you actually be politicians; shouldn’t more scientists be politicians themselves?
Lord Martin Rees: Well, I think they should interact with politicians. I do not know whether you are in academia but, if you see how academics run their own affairs – they cannot claim greater wisdom and common sense than the average members of the public. So I think they should be aware that politics is a very difficult art indeed. But I think in the UK we have been very fortunate in that we have had two prime ministers who have been very committed to these issues and three ministers – the Miliband brothers and Hilary Benn – in key ministries who have all given high priority to environmental issues and climate and energy issues. So they have done this, and I hope the fact that they interact quite a lot with scientists has helped to give them their own attitudes. But it is very important indeed that, even though scientists are not active politicians, those of us who are privileged to have the chance to meet politicians should do all we can to ensure that they are as well informed as possible.
Question: You mentioned that the public has a high degree of trust in scientists and yet, as we have just been commenting, if you read the media, science seems almost to be under siege with the climate change debate and the debate about evolution. So I wondered if you think this is just a transitory thing because of the politics around those issues at the moment, or is it something that is likely to lead to a more sustained undermining of trust in science; and I am interested in what you think scientists themselves and the broader community should be doing about that.
Lord Martin Rees: It is certainly depressing that large numbers of people claim that they do not believe in evolution and claim that there is no evidence that motivates concern about climate change; I think this is indeed a problem. I think the media could perhaps do more by, as I say, not giving equal weight to all opinions. But I think the evolution debate is more surprising because it is astonishing that the evidence for evolution is not taken seriously by seemingly 40 per cent of people. Given that, I am not at all surprised that the evidence on which climate policy is based is not accepted by everyone – because it is rather indirect, it is rather arcane and the effects are as yet small; they are based on measurements, like carbon dioxide measurements which are hard to make. So I am less surprised that people are sceptical about climate science than I am that they are sceptical about evolution.
But I think the other point about climate science is that the way in which politicians rightly respond to climate science is to make suggestions which might seem to involve some sacrifice by people and that, of course, makes people naturally very sceptical. For that reason, I think it is very important that, in politics, one should focus on the short term and the ways in which we can actually improve energy efficiency and save money and develop new technologies; and any country that gets a lead in developing clean technologies will have a tremendous economic advantage. So I think what politicians should do, whether they are motivated by climate change or not, is push very hard for improved efficiency in energy use and energy generation, because that is something which, on all grounds, is surely a good thing to do; and that should demand a consensus in a way that perhaps the more arcane argument does not.
