Lord Rees of Ludlow is Astronomer Royal at the University of Cambridge's Institute of Astronomy, and founder of the Centre for the Study of Existential Risk. This blog post, the first in a three-part series, is based on a lecture he gave at the IPR on 9 February.
A few years ago, I met a well-known Indian tycoon. Knowing that I had the title of Astronomer Royal, he asked: ‘do you do the queen’s horoscopes?’ I responded, with a straight face: ‘If she wanted one, I’m the person she’d ask’. He then seemed eager to hear my predictions. I told him that stocks would fluctuate, there’d be new tensions in the Middle East, and so forth. He paid rapt attention to these ‘insights’. But I then came clean. I said I was just an astronomer – not an astrologer. He then lost all interest in my predictions. And rightly so; scientists are rotten forecasters – almost as bad as economists.
Nor do politicians and lawyers have a sure touch. One rather surprising futurologist was Lord Birkenhead, crony of Churchill and Lord Chancellor in the 1920s. He wrote a book entitled ‘The World in 2030’. He’d read Wells and Bernal – he envisaged babies incubated in flasks, flying cars and suchlike fantasies. In contrast, he foresaw social stagnation.
Here’s a quotation: “In 2030 women will still, by their wit and charms, inspire the most able men towards heights that they could never themselves achieve.”
I’m going to make forecasts, but – mindful of these precedents – very tentatively.
Astronomers think in billions of years. But even in that perspective this century is special. The Earth has existed for 45 million centuries – humans for a few thousand centuries. But this century is special: it’s the first when one species, ours, has the planet’s future in its hands. We’re deep in an era that’s called the Anthropocene. We could irreversibly degrade the biosphere, we could trigger the transition from biological to electronic intelligences, or misdirected technology – bio or cyber – could cause a catastrophic setback to civilisation.
Twelve years ago I wrote a book on this theme which I entitled Our Final Century? My publisher deleted the question-mark. The American publishers changed the title to 'Our Final Hour'. (Americans seek instant gratification – and the converse).
I didn’t think we’d wipe ourselves out. But I did think we’d be lucky to avoid devastating setbacks – and we’ve had one lucky escape already.
At any time in the Cold War era – when armament levels escalated beyond all reason – the superpowers could have stumbled towards armageddon through muddle and miscalculation.
Nuclear weapons are based on 20th century science. I’ll focus later in my argument on 21st century sciences – bio, cyber, and AI – which offer huge potential benefits, but also expose us to novel vulnerabilities
But before that let’s focus on the long-term threats that stem not from conscious decisions, bur from humanity’s ever-heavier collective ‘footprint’. Even with a cloudy crystal ball there are some things we can predict. For instance, it’s almost inevitable that by mid-century, the world will be more crowded.
Fifty years ago, world population was about 3 billion. It now exceeds 7 billion. But the growth is slowing. Indeed, the number of births per year, worldwide, peaked a few years ago and is going down. Nonetheless world population is forecast to rise to around 9 billion by 2050. That’s partly because most people in the developing world are young. They are yet to have children, and they will live longer. The age histogram in the developing world will become more like it is in Europe.
Experts predict continuing urbanisation – 70 percent of people in cities by 2050. Even by 2030 Lagos, São Paulo and Delhi will have populations above 30 million. To prevent megacities becoming turbulent dystopias will surely be a major challenge to governance.
Population growth seems currently under-discussed. That is maybe because doom-laden forecasts in the 1970s, by the Club of Rome, Paul Erlich and others, have proved off the mark. Up until now, food production has more than kept pace – famines stem from wars or maldistribution, not overall shortage. And it’s deemed by some a taboo subject – tainted by association with eugenics in the 1920s and 30s, with Indian policies under Indira Gandhi, and more recently with China's hard-line one-child policy.
Can 9 billion people be fed? My layman’s impression from reading the work of experts is that the answer’s yes. Improved agriculture – low-till, water-conserving, and perhaps involving GM crops – together with better engineering to reduce waste, improve irrigation, and so forth, could sustainably feed that number by mid-century. The buzz-phrase is ‘sustainable intensification’.
But there will need to be lifestyle changes. The world couldn't sustain even its present population if everyone lived like Americans do today– using as much energy per person and eating as much beef.
Population trends beyond 2050 are harder to predict. They will depend on what people now in their teens and 20s decide about the number and spacing of their children. Enhanced education and the empowerment of women – surely a benign priority in itself – could reduce fertility rates where they’re now highest. And the demographic transition hasn’t reached parts of India and Sub-Saharan Africa.
If families in Africa remain large, then according to the UN that continent’s population could double again by 2100 to 4 billion, thereby raising the global population to 11 billion. Nigeria alone would by then have as big a population as Europe and North America combined, and almost half of all the world’s children would be in Africa.
Optimists remind us that each extra mouth brings also two hands and a brain. Nonetheless, the higher the population becomes, the greater will be all pressures on resources – especially if the developing world narrows its gap with the developed world in its per capita consumption – and the harder it will be for Africa to escape the ‘poverty trap’. So we must surely hope that the global figure declines rather than rises after 2050.
Moreover, if humanity’s collective impact on nature pushes too hard against what Johan Rockstrom calls ‘planetary boundaries’, the resultant ‘ecological shock’ could irreversibly impoverish our biosphere. Extinction rates are rising; we’re destroying the book of life before we’ve read it. Biodiversity is a crucial component of human wellbeing. We're clearly harmed if fish stocks dwindle to extinction; there are plants in the rainforest whose gene pool might be useful to us. But for many environmentalists, preserving the richness of our biosphere has value in its own right, over and above what it means to us humans. To quote the great ecologist E O Wilson, ‘mass extinction is the sin that future generations will least forgive us for’.
The world’s getting more crowded. And there’s a second firm prediction: it will gradually get warmer. In contrast to population issues, climate change is certainly not under-discussed.
The famous Keeling curve shows how the concentration of CO2 in the air is rising, mainly due to the burning of fossil fuels. It’s still unclear how much the climatic effects of rising CO2 are amplified by associated changes in water vapour and clouds. The fifth IPCC report presents a spread of projections.
But despite the uncertainties there are two messages that most would agree on:
- Regional disruptions to weather patterns within the next 20-30 years will aggravate pressures on food and water, and engender migration.
- Under ‘business as usual’ scenarios we can’t rule out, later in the century, really catastrophic warming, and tipping pints triggering long-term trends like the melting of Greenland’s icecap.
But even those who accept both these statements have diverse views on the policy response. It’s important to realise that these divergences stem less from differences about the science than from differences in economics and ethics – in particular, in how much obligation we should feel towards future generations.
Economists who apply a standard discount rate (as, for instance, Bjorn Lomberg’s Copenhagen Consensus does) are in effect writing off what happens beyond 2050 – so unsurprisingly they downplay the priority of addressing climate change in comparison with shorter-term efforts to help the world’s poor.
But if you care about those who’ll live into the 22nd century and beyond, then, as economists like Stern and Weizman argue, you deem it worth paying an insurance premium now, to protect those generations against the worst-case scenarios.
So, even those who agree that there’s a significant risk of climate catastrophe a century hence will differ in how urgently they advocate action today. Their assessment will depend on expectations of future growth, and optimism about technological fixes. But, above all, it will depend on an ethical issue – in optimising people’s life-chances, should we discriminate on grounds of date of birth?
(As a parenthesis, I’d note that there’s one policy context where a discount rate of essentially zero is applied – radioactive waste disposal, where the depositories are required to prevent leakage for 10,000 years. This is somewhat ironic, when we can’t plan the rest of energy policy even 30 years ahead)
Consider this analogy. Suppose astronomers had tracked an asteroid, and calculated that it would hit the Earth in 2080, 65 years from now – not with certainty, but with (say) 10 per cent probability. Would we relax, saying that it’s a problem that can be set on one side for 50 years – people will then be richer, and it may turn out then that it’s going to miss the Earth anyway? I don’t think we would. There would surely be a consensus that we should start straight away and do our damnedest to find ways to deflect it, or mitigate its effects.
What will actually happen on the climate-policy front? The pledges made at the Paris conference are a positive step.
But even if they’re honoured, CO2 concentrations will rise steadily throughout the next 20 years. By then, we'll know with far more confidence – from a longer timebase of data, and from better modelling – just how strong the feedback from water vapour and clouds actually is. If the so-called ‘climate sensitivity’ is low, we’ll relax. But if it’s large, and climate consequently seems on an irreversible trajectory into dangerous territory, there may then be a pressure for 'panic measures'. This could involve a 'plan B' – being fatalistic about continuing dependence on fossil fuels, but combatting its effects by either a massive investment in carbon capture and storage, or else by geoengineering.
It’s feasible to inject enough aerosols into the stratosphere to cool the world’s climate – indeed, what is scary is that this might be within the resources of a single nation, or even a single corporation. There could be unintended side-effects; moreover, the warming would return with a vengeance if the countermeasures were ever discontinued – and other consequences of rising CO2 (especially the deleterious effects of ocean acidification) would be unchecked.
Geoengineering would be a political nightmare: not all nations would want to adjust the thermostat the same way. Very elaborate climatic modelling would be needed in order to calculate the regional impacts of an artificial intervention. (The only beneficiaries would be lawyers. They’d have a bonanza if nations could litigate over bad weather!).
I think it’s prudent to explore geoengineering techniques enough to clarify which options make sense, and perhaps damp down undue optimism about a technical 'quick fix' for our climate.
Many still hope that our civilisation can segue smoothly towards a low-carbon future. But politicians won't gain much resonance by advocating a bare-bones approach that entails unwelcome lifestyle changes – especially if the benefits are far away and decades into the future. But three measures that could mitigate climate change seem politically realistic.
First, all countries could improve energy-efficiency, insulate buildings better, and so forth—and thereby actually save money.
Second, we could target cuts to methane, black carbon and CFC emissions. These are subsidiary contributors to long-term warming. But unlike CO2, they cause local pollution too – in Chinese cities, for instance – so there’s a stronger incentive to reduce them.
But third, nations should expand R&D into all forms of low-carbon energy generation (renewables, 4th generation nuclear, fusion, and the rest), and into other technologies where parallel progress is crucial – especially storage (batteries, compressed air, pumped storage, flywheels, etc) and smart grids. That’s why an encouraging outcome of Paris was an initiative called ‘Mission Innovation’. It was launched by President Obama and the Indian Prime Minister Modi, and endorsed by the G7 nations, plus India, China and 11 other nations. It’s hoped they’ll pledge to double their publicly funded R&D into clean energy by 2020 and to coordinate efforts. There’s been a parallel pledge by Bill Gates and other private philanthropists.
This target is a modest one. Presently, only 2 per cent of publicly funded R&D is devoted to these challenges. Why shouldn’t the percentage be comparable to spending on medical or defence research?
The faster these ‘clean’ technologies advance, the sooner will their prices fall so they become affordable to developing countries – where more generating capacity will be needed, where the health of the poorest billions is jeopardised by smokey stoves burning wood or dung, and where there would otherwise be pressure to build coal-fired power stations.
It would be hard to think of a more inspiring challenge for young engineers than devising clean energy systems for the world.
All renewables have their niches – wind, tides, waves and hydro here in the UK, for instance. But an attractive scenario for Europe might be large-scale solar energy, coupled with a transcontinental DC smart grid network (north-south to transmit power from Spain or even Morocco to the less sunny north, and east-west to smooth over peak demand in different time-zones) with efficient storage as well.
Of course the unique difficulty of motivating CO2 reductions is that the impact of any action not only lies decades ahead, but is globally diffused. In contrast, for most politicians the immediate trumps the long term; the local trumps the global. So climate issues, which gained prominence during the Paris conference, will slip down the agenda again unless there’s continuing public concern.
For more information on Lord Rees' IPR lecture, please see our writeup here.
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