IN THE once-seedy district of Soho, about 10 minutes鈥 walk from 快猫短视频鈥榮 London offices, a pump, a plaque and a pub commemorate one of the greatest ever breakthroughs in human history: a decisive step made almost 200 years ago towards conquering infectious disease.
Our current global health crisis is a reminder of how little we want to return to the days when deadly infections carried away most of us. Yet also in some way, advances back then were a first step on a path towards planetary perdition. The success against infectious disease, alongside other major developments, dramatically improved our survival and set humanity鈥檚 numbers soaring, from little more than 1.25 billion people back then to 7.7 billion now.
Now, climate change, biodiversity loss, the degradation of the biosphere and, yes, coronavirus are forcing us to consider the legacy of that success. The pandemic is becoming the latest focus for an old, uniquely contentious question: are there just too many of us on the planet?
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The basic argument is hard to deny. With fewer of us around, there would be fewer greenhouse gas emissions, less pollution and waste, more space for both us and the rest of the natural world to survive and thrive.
So let鈥檚 bite the bullet. Let鈥檚 talk about population 鈥 where it is heading globally, what that means for the planet, and what, if anything, we should be doing to limit its growth. Be warned, however: finding answers isn鈥檛 nearly as easy as posing questions. And with scenes of sexism, racism, nationalism, misogyny and eugenics, what follows at times makes for uncomfortable viewing.
The boom in our ranks over the past century or so has one source: progress. In 1854, when local doctor John Snow worked out how cholera was being transmitted through an infected water pump handle on Broad Street in Soho, more than a half of all deaths in England were caused by infectious disease. Average life expectancy hovered around 40.
But starting in the 19th century in rapidly industrialising economies, a series of leaps in health and sanitation began to depress mortality across the globe. Meanwhile, more efficient methods of agricultural production and improved nutrition allowed more people to live more comfortably, for longer, without extreme hunger. In 1860, . Today, it is around 4 per cent, and a fraction of a per cent in advanced economies. In western Europe, . In sub-Saharan Africa, , up from 44 half a century ago.
This change in death rates marks the first stage in the 鈥渄emographic transition鈥: a seismic change in which nations shift over decades from high birth and death rates to lower rates of both. Few people have a problem with its first stage. 鈥淓verybody is happy with mortality decline,鈥 says Diana Coole, a political scientist at Birkbeck, University of London.
But as more people live longer lives, populations skyrocket. The global population of around 1 billion in 1800 had doubled by the late 1920s , it had doubled again, approaching 4 billion. Half a century later, it is about to have doubled again, .
鈥80 million
The expected global population growth in 2020鈥
And so it goes on. This year, more than twice as many people will be born as will die. Humanity鈥檚 numbers will swell by something like 80 million, pandemic or no pandemic. The United Nations Population Division鈥檚 that 9.7 billion people will be on the planet in 2050 and 10.9 billion in 2100. These figures are based on the average global fertility rate, defined as the number of births per woman. Increase that rate by half a child, and you hit a 鈥渉igh variant鈥 of almost 16 billion people at the end of the century (see graph below).
鈥淭here鈥檚 not a lot of difference in population projections over the next 30 or 40 years,鈥 says , head of the UN Population Division. 鈥淏ut they start to diverge in the second half of the century and, honestly, nobody knows for sure. Nobody can know in that kind of time interval.鈥
That鈥檚 not exactly reassuring. 鈥淵ou can鈥檛 read the high-population variant without thinking, 鈥極h my God鈥,鈥 says Coole.
On the face of it, fewer people means less impact. Take climate change, perhaps the most immediately pressing of our many environmental problems. In 2017, and her colleague Seth Wynes at Lund University in Sweden studied the measures people in advanced economies could take to reduce their carbon footprint. Once they accounted for the generational effect 鈥 that every child a person has is likely to have children themselves 鈥 , saving 120 tonnes of carbon dioxide a year for the average US citizen. The next-biggest impact, living car-free, came in at 3 tonnes of CO2 a year for the average person in the US. Trailing in behind that were avoiding flying, buying green energy and switching to a plant-based diet. 鈥淗aving a child is a huge life decision personally and professionally and financially and every other way,鈥 says Nicholas. 鈥淚t has a huge impact on the carbon legacy that we leave in the atmosphere.鈥
It isn鈥檛 just carbon emissions. 鈥淒eclining biodiversity is both an issue of increasing human number and unsustainable consumption,鈥 says Edu Effiom at the Cross River State Forestry Commission in Calabar, Nigeria. She was lead author for the Africa section of the 2019 UN-backed report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, which . That human numbers are a major driver in this too seems undeniable: you can draw a graph showing human numbers and species extinctions growing in lockstep. Our ravaging of safe spaces for nature is thought to provide new avenues for 鈥渮oonotic鈥 diseases such as the new coronavirus to jump over from other species to our own.
鈥淭he bottom line is, there is an overshoot in our demand for nature,鈥 says economist at the University of Cambridge. Our environmental impact is primarily determined by three things, he says: how much each of us consumes, the efficiency of our technology in converting natural resources into products we consume and how many of us there are. But we don鈥檛 tend to talk about the final point. 鈥淲e miss out this one factor, number,鈥 he says.
Public discourse hasn鈥檛 always been so coy. Concerns about the ability of the planet to sustain so many of us date back at least two centuries, to the . In the 1960s, the first wave of the environmental movement brought soul-searching about global population numbers when they were barely half what they are today. In 1972, the Club of Rome, a grouping of prominent politicians, economists, scientists and diplomats, published , a report that used computer modelling to predict the collapse of global systems in the mid-to-late 20th century if then-current trends of population growth and resource consumption were to continue.
鈥10.9 billion
The UN鈥檚 median world population projection for 2100鈥
They did continue, and civilisation hasn鈥檛 so far collapsed. The 鈥済reen revolution鈥 in agriculture began to kick in from the late 1960s, allowing more people to be fed more securely. And the second phase of the demographic transition began in earnest, as birth rates started to fall worldwide. The drivers of this process are complex, but relate to increasing urbanisation, education and material progress. Rising levels of education lead to more people having fewer children and at a later age. Healthier, better educated women are more likely to stake their rights to opportunities beyond bearing and caring for children. Widespread availability of abortion and contraception assist those trends.
If we are looking for reasons why the mid-20th-century wave of population worry receded, it is that, from a high point of well over 2 per cent a year in the late 1960s, the global rate of population growth has now . Across large swathes of Europe and South America, fertility rates are at or close to the 鈥渞eplacement rate鈥 of 2.1 children per woman, the level that ensures a stable population. In some parts of the world, notably Japan, South Korea, Russia and some nations in eastern and southern Europe, fertility is below this rate, and population is declining. But even in those places where it is still increasing 鈥 South Asia, Africa, the Middle East 鈥 fertility is going down.
One basic problem in talking about human population is not knowing where those trends are going next. UN projections are largely based on applying models of the second phase of the demographic transition, the fall in birth rates, in places that have already been through it to places that haven鈥檛.
is a demographer at the International Institute for Applied Systems Analysis in Austria, and one of 15 scientists selected by the UN to produce its latest , released in September 2019. He is an outspoken critic of that approach. 鈥淚 call it blind statistical extrapolation,鈥 he says: modelling with insufficient real-world data from the countries in question.
Lutz and his colleagues did, and the UN models are too crude to take account of that. 鈥淲e鈥檝e seen this in every Asian country, and now we鈥檙e seeing it again in every African country,鈥 says Lutz. 鈥淰irtually everywhere, women with higher education have a lower fertility, lower birth rate, than the less educated,鈥 he says. And nowhere, at least before the pandemic, has access to education been improving faster than in parts of Africa.
Ups and downs
Lutz鈥檚 latest model of population growth, published in 2018, traces future possibilities according to five for global development. They look very similar to the UN scenarios up to 2050, but then diverge rapidly 鈥 downwards. In all but one, ; in the 鈥渕edian assumptions scenario鈥, at around 9.5 billion in 2070. In two cases, it ends up below where it is today.
This optimistic picture has acquired some traction, with books such as 2019鈥檚 . So could it be that population is a problem that is about to solve itself?
Not according to Wilmoth. 鈥淭here鈥檚 really no argument for saying that change in the future will be faster than it was in the past,鈥 he says. 鈥淚f anything, I think what we worry about at the UN is that the pace of change may be slower than what we鈥檙e predicting.鈥
The worsening climate crisis would certainly seem to suggest caution: rising population is still rising population. Coole is also sceptical that we are reaching the closing scenes of a grand historical narrative that ends inevitably with low mortality and fertility rates. In fact, she is worried recent trends might be about to go into reverse. Everyone is happy about mortality decline, but it is a different story with fertility decline.
There are many reasons why people and groups across the world adopt 鈥減ronatalist鈥 positions arguing for higher fertility. One is that, while environmental considerations might suggest that lower fertility rates are good, economic considerations often suggest they aren鈥檛, at least on models of economic growth based on more people creating more demand for goods and services. Developing economies are certainly reaping the rewards of young, dynamic populations as their workforces boom 鈥 just as today鈥檚 advanced economies did earlier. 鈥淚f you go to India, it鈥檚 incredible the change in 10 years,鈥 says Coole. 鈥淵ou can see why they feel this is something they want to have.鈥
鈥淩ising levels of education lead to more people having fewer children and at a later age鈥
Nations further along the demographic transition, where fertility rates are bumping along at replacement level or below, are grappling with the opposite problem. With fewer people around, economic growth, stable finances and societal cohesion become harder to maintain. In states with highly developed welfare systems, this becomes a slow-burn issue of a growing 鈥渄ependency ratio鈥: a large, ageing, economically inactive population supported by tax receipts from a dwindling band of working people.
The solutions to these problems 鈥 higher taxes, less generous welfare provision, later retirement 鈥 have themselves turned into political hot potatoes in many advanced economies. One alternative 鈥 higher levels of immigration to maintain working-age populations 鈥 is even more fraught. Japan has gone down a different route: pursuing robotics as a way of replacing people not being born.
The challenges associated with ageing populations are a big factor in the success of nationalist populist movements in many parts of the world. Certainly, rhetoric advocating population growth as a matter of national destiny is on the rise in countries including Hungary, Italy, Iran and elsewhere.
Another such nation is Turkey. Under president Recep Tayyip Erdo臒an, it has pursued policies in favour of population growth and has been trying to roll back women鈥檚 rights to achieve it. Access to abortion, although still a legal right until the 10th week of pregnancy, has been de facto limited in many places, says a political scientist at Bilgi University in Istanbul. 鈥淭his period has also witnessed a political emphasis persistently put on the family as a social institution in a way which puts women in a secondary position, defining them as mothers and caretakers, and threatening their individual rights and capabilities,鈥 she says. In Poland, which also has a vocal pronatalist contingent, a high court just ruled to ban nearly all abortions.
This is a depressingly familiar story, says Coole. 鈥淩ight across the world, we see women鈥檚 rights being curtailed by people trying to increase population.鈥 That has a certain irony about it, because a desire not to interfere with women鈥檚 reproductive rights is another reason why, starting in the 1970s, talk about population control receded.
Pronatalist sentiment does bring together often bizarre coalitions of otherwise irreconcilable interests. Populists who dream of national glory are united with pluralists who support the right of all countries to develop as they see fit. Free marketeers who reject notions of state regulation share common cause with advocates for comprehensive social welfare systems worried about the effect of ageing and declining populations. Social and religious conservatives who oppose abortion and contraception find their interests aligned with those of feminists fighting for a woman鈥檚 right to choose how many children she has.
The influence of religion is worth dwelling on a while. In 1968, Pope Paul VI condemned artificial contraception. This interdiction, while widely disregarded, still stands for the planet鈥檚 1-billion-plus Roman Catholics. Meanwhile, under pressure from religious and social conservatives, every Republican president in the US since Ronald Reagan has ruled out giving funding to any aid organisation that supports abortion, even in principle 鈥 including the UN Population Fund.
Those who suggest there might be a case for reducing population growth must certainly be prepared for a sometimes personal backlash. Nicholas stumbled onto this thorny territory with her study of the carbon effects of having one fewer child. Some, mainly male, critics, including the right-wing shock jock Rush Limbaugh, , while some feminist critics suggested she was attempting to shift the blame for climate change from corporations and governments to women鈥檚 reproductive choices.
鈥160:1
The relative climate impacts of average citizens from the US and Ethiopia鈥
鈥淭he decision to have a child is a deeply personal one, as it should be,鈥 says Nicholas. 鈥淥ur study provided information to inform choices, but people react very strongly and emotionally if they feel their decisions are being threatened or attacked.鈥 Coole says she has had similar experiences if she seemed to imply limiting reproductive freedom: 鈥淚f I mentioned it, say, in the States, feminists would treat me as if I was some kind of Nazi.鈥
That word is extreme, but it crops up a lot in discussions that touch on limiting human numbers. The genocides committed by the Nazi regime followed on from a long history of Western scientists advocating eugenics to 鈥渃leanse鈥 populations of supposedly undesirable traits. That history dogs the conversation today. 鈥淚t really caused problems among Western intellectuals,鈥 says Dasgupta. 鈥淭he moment you talked about population, you were talking about coercion.鈥
No one who talks thoughtfully about population today is advocating that. In 1967, the UN recognised , and how many, as a fundamental human right. Anti-natalism via coercion has been tried several times, with generally disastrous consequences for human rights. Sterilisation programmes across the US during the 20th century disproportionately targeted women from minority communities. China鈥檚 infamous one-child policy, in place from 1979 to 2013, led to widespread selective abortion of female fetuses, as well as the enforced sterilisation of women. In some parts of India, more than 6 million men with more than two or three children during a state of emergency from 1975 to 1977. Partially funded by aid money from the US and elsewhere, it was widely seen to have had an anti-Muslim agenda. The spectre of eugenics, again.
鈥淪ometimes countries have reacted with such aggressive measures that they became violations of human rights,鈥 says Wilmoth. 鈥淭hey became convinced that it was necessary for the collective good and invading people鈥檚 bedrooms and women鈥檚 wombs was justified to control population growth.鈥
So talking about population is fraught. But it is at this point that we need to take a closer look at the trap we have been skirting for some time while doing just that. Call it the 鈥渢hem鈥 versus 鈥渦s鈥 trap.
Most of us, when asked to think about our own lives and those of the people around us, would probably find ourselves taking an instinctively pronatalist position. I don鈥檛 have children myself, but I certainly wouldn鈥檛 tell a relative or friend that they shouldn鈥檛 have a child if they want to. I would be even less happy if any third party, state or otherwise, were to start telling me or anyone close to me how many kids we could have.
Yet if we say that global birth rates are too high and need to be brought down, we are sailing dangerously close to saying something similar would be OK elsewhere. 鈥淭he discussion is almost always: we want to see fewer people of the other kind, of the other race, of the other nationality,鈥 says Lutz. 鈥淵ou always want to see fewer of the other and more of your own.鈥
Back to basics
It is the case that in places like the UK, fertility rates bump along below the replacement rate 鈥 and . Meanwhile, in parts of the globe, notably parts of central Africa, fertility rates are still running at three, four, five or more children per woman. In the UN medium-variant population scenario, half of the global population increase by 2100 comes from just nine countries, eight of them developing economies: India, Nigeria, Pakistan, the Democratic Republic of the Congo (DRC), Ethiopia, Tanzania, Indonesia and Egypt. The US, with high levels of immigration and a relatively young population for an advanced economy, comes in at number nine.
But for Lutz, arguments based on raw numbers alone are flimsy. 鈥淧eople are focused way too much on world population size, which is in a way a figure that affects nobody鈥檚 life, because what you experience is the population growth in your neighbourhood, or at most in your country,鈥 he says.
It is here we need to go back to basics. The justification for talking about population in the first place is our concern about humanity鈥檚 impact on the planet, so we have to look at where that impact is coming from. In the case of climate change, that is pretty clear. 鈥淚f you look historically over time at what has driven the increase in carbon emissions in the atmosphere, sure, population growth has been an important factor, but a larger factor has been the change in per-capita emissions,鈥 says Wilmoth. 鈥淒epending on how you measure it, over which time period, for which population and so forth, it鈥檚 something like two-thirds versus one-third: two-thirds behaviour and one-third human numbers.鈥
That switches the spotlight away from fertility rates in 鈥渙ther鈥 parts of the world back to the consumption levels of people sitting in relative prosperity in advanced economies. 鈥淧oor people in Africa where the population is growing most rapidly are not contributing at all to greenhouse gas emissions,鈥 says Lutz.
Let鈥檚 put some numbers on that. The World Bank says that, in 2014, the last year for which comprehensive figures are available, . For China, it was 7.5, for the US, it was 16.5, for Australia 15.4. For the average member of advanced-economy club the Organisation for Economic Co-operation and Development, that figure was 9.6. The equivalent numbers for the eight developing economies projected to have the largest population increases according to the UN鈥檚 figures are these: India 1.7 tonnes per capita, Nigeria 0.5, Pakistan 0.9, the DRC 0.1, Ethiopia 0.1, Tanzania 0.2, Indonesia 1.8 and Egypt 2.2. To take, admittedly, the most extreme of those numbers, around 160 citizens of Ethiopia or the DRC have a lower climate impact than one US citizen.
Such simplistic calculations have flaws, of course. Emissions from advanced economies have been declining or flatlining in recent years, whereas those from developing economies are rising as they develop and gain a consumption-hungry middle class. The lifetime difference in emissions between the average person born in India and the US today, for example, may be smaller than the numbers suggest.
Nor do greenhouse gases say everything about our impact on life鈥檚 support systems. And while not all of the destruction of the Amazon rainforest, say, is down to rapacious multinationals satisfying the demands of Western consumers, a basic equation holds: while the number of people on the planet is important, says Effiom, 鈥渦nsustainable consumption by the developed region of the world is a major factor in biodiversity decline鈥.
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鈥120 tonnes
Reduction in annual carbon dioxide emissions by an average US citizen having one child fewer鈥
As for pandemics, while our destruction of nature and encroachment on wild habitats undoubtedly doesn鈥檛 help, it is difficult to pinpoint a causal link between their likelihood or severity and
the number of us on the planet: deathly pandemics have, after all, occurred throughout recorded human history, Coole points out. Nor is it easy to argue that more people living cheek by jowl in cities necessarily spurs them. The John Snow story shows how urbanisation has over history provided people with access to modern sanitation and medical knowledge and care that can limit the spread of disease. One facet of high consumption, meanwhile 鈥 criss-crossing the world on planes 鈥 almost undoubtedly did facilitate the virus鈥檚 spread.
The looming climate change emergency gives us another reason to hold back from suggesting population control as the solution to the world鈥檚 woes. Given the impact of having more children extends over generations, having fewer of them won鈥檛 help us in the decade or so we have to get emissions down and avoid catastrophic global warming. 鈥淧opulation is an important long-term factor in how much warming we eventually experience, but for the climate we live out our lives in, as well as what future generations inherit, it is absolutely critical to stop today鈥檚 climate pollution,鈥 says Nicholas. That suggests the emphasis for people in advanced economies should be rethinking their consumption-fuelled economic models, while helping people elsewhere to develop more sustainably.
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The number of children we have is part of that consumption calculation. 鈥淛ust as people are thinking more about their diet and about flying around the world, the good thing would be for people to appreciate the impacts before they start thinking about reproduction,鈥 says Coole.
But there is a limit to how far we can take those discussions. 鈥淲e have to accept population trends to a certain degree,鈥 says Wilmoth. 鈥淲e have to accept the changes that are going to take place, and the world has to adapt its ways of living. Unless you stop people from having babies entirely, and that would have enormous consequences we don鈥檛 even want to think about.鈥
Instead, we need to press for more of what works in reducing population growth where population growth is high: education, and support for family planning and gender equality. 鈥淚t means supporting programmes to give people access to modern contraceptives all round the world,鈥 says Wilmoth. Effiom agrees, citing the importance of, for example, stronger measures against polygamy and forced marriage. 鈥淚t鈥檚 about enhancing girls鈥 education and empowering them to make choices for themselves,鈥 she says.
鈥淗aving fewer children won鈥檛 allow us to get emissions down fast enough鈥
That doesn鈥檛 mean we shouldn鈥檛 talk about population. But if we do, perhaps we should ask ourselves a series of questions first. Is our motivation concern about the fate of the planet and the impact of humanity on it? If so, are we taking steps to limit our own impact, and supporting public efforts to do the same? Do we accept that humanity鈥檚 impact is an 鈥渦s鈥 problem, not just a 鈥渢hem鈥 problem? Do we support the right of individuals, especially women, to choose how they live their lives, and aren鈥檛 tacitly advocating draconian measures being applied to people that we wouldn鈥檛 accept being applied to ourselves? If we can sincerely answer 鈥測es鈥 to all those questions, then let鈥檚 talk 鈥 while acknowledging there may be more productive ways to move from our path of planetary perdition.
