This article was first published in the January 2019 edition of BBC History Magazine


Q: What exactly is ‘demography’, and why do you think it is an enlightening way to look at history?

A: In some ways demography is quite simple, and that’s part of its appeal. It’s essentially about three things: the people entering the world, the people leaving it and the people moving across it – births, deaths and migration. So why does it have such an impact? Because the number of people in any given area, and the age and ethnic composition of that population, affect an area’s politics, economics, society and culture. In fact, it’s very hard to think of aspects of life that are not impacted by demography in one way or another.

Q: Your book looks at population trends over the last 200 years. What have been the biggest changes in that time?

A: Throughout human history there’s always been population growth and decline, but before the 19th century things were rather random. Around 1800, however, a pattern started emerging, which sees death rates falling while fertility rates stay high, meaning that a population grows until eventually the birth rate falls and the population stabilises. Why did this happen? Modernity. When you start to get basic public health measures and education on how to implement them, death rates fall very quickly. This pattern began in Britain, and then spread across Europe and the world.

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Queen Anne, based on a work by Sir Godfrey Kneller, c1702–10. Anne's reign saw women take centre stage in fierce political debates. (Photo by Bridgeman/National Trust Photographic Library)

Q: How did this pattern affect the balance of global power?

A: It’s very important that the first population explosion happened in Britain. Britain had a number of environmental, cultural and institutional advantages that meant it was the first significantly-sized country to go through modernisation. In the 19th century, Britons became better educated, better housed, better fed and were more likely to get basic medical care. This meant they experienced an early fall in death rates, so the population ballooned. Without its first-mover advantage, Britain could never have become ‘the workshop of the world’ – the industrial revolution couldn’t have kept its momentum up without a large and growing population. This early population boom also essentially led to the British empire, with a huge movement of people from the British Isles to far flung parts of the globe. The world we know today, full of English-speaking countries, is the product of that rollercoaster of Anglo demography – population explosion and mass emigration, which then spread across Europe.

Today, of course, the migration is the other way around. At several points in the 21st century, we’ve seen hundreds of thousands of people a year move to the UK. Similarly, if you told somebody in France in 1900 that by 2018 we would have huge Algerian populations in Paris and Marseille, and no French populations in Algiers, they would have been absolutely astonished.

Q: Tell us about the connection between population and war.

A: On a very basic level, the number of fighters you can throw onto the battlefield is hugely significant. If you look at the battles on the First World War’s western front, it was a grinding competition of pouring ever more men into the trenches. When the quality of the soldiers’ training and armaments was broadly similar, numbers mattered enormously. That gave the Allies an edge, and when America entered the war it was the final straw. You could say that the First World War was determined in the cradles of the 1880s and 1890s.

But it’s more complex than a pure numbers game. The age of a population is another factor: young populations can result in a lot of conflict, violence and fanaticism. It’s certainly true that if Syria (which has a median age of 20) had a population the age of Switzerland (where it’s well over 40), things would have turned out differently there. When you get to a certain age, you have interests: you’re more likely to be married with children and have more of an economic stake in society. Something you almost exclusively find is that when a population gets old, it has less crime, violence and civil strife.

There is also some evidence to support the argument that as family sizes decrease, parents value their children more intensely. Families with one son are less willing to send him off to fight than a family with four sons. However, my sister has four sons, and I imagine she would disagree with that!

A young population is more likely to result in conflict, violence and fanaticism

Q: You suggest that populations can be remarkably resilient…

A: I don’t mean this to sound heartless or cruel, as I do recognise that every life is valuable. But yes, these big cataclysmic events don’t actually have as much impact as you might think. For example, the First World War and the 1918 Spanish flu pandemic: these did slow population growth in Europe, but even the millions of deaths they caused weren’t enough to stop that growth entirely.

A current example would be Syria. Syria’s population is about 20 million, and the country has lost around half a million in war casualties (not including people who have emigrated). Just in raw numbers, those losses could be recuperated in a very small space of time. Syria could see its population growing at 2 or even 3 per cent a year.

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Q: What is the most important factor in population change?

A: For me, it has to be birth rates. Where contraception and education are available, and women have a choice, it’s a given that they have smaller families. Outside sub-Saharan Africa, there’s barely a country in the world where women have more than four children now. The fall in fertility rates across the globe in recent times is staggering. What I call the ‘infertile crescent’ now stretches from Spain to Singapore. One statistic that floors me is that between 1970 and 1980, China’s birth rate fell from 6 to 3 in a decade, and that was before the one-child policy was introduced. You simply can’t get much faster falls in fertility than that. Decisions like how many children to have feel very personal, but the individual choices you make are shaped by big social forces. And what’s fascinating is how different cultural, social and economic settings lead people to make different choices on aggregate.

Q: You talk about ‘demographic engineering’ – what does that involve?

A: Demographic engineering is when groups in conflict use demography in order to strengthen their hand against the other side. I talk about two types: hard and soft.

Hard demographic engineering is when you change a population through demographic factors themselves – attempting to manipulate birth rates, death rates or migration. In its most extreme form it could even include genocide. One example of hard demographic engineering would be Northern Ireland’s Protestant establishment encouraging Catholics to emigrate in the 1960s and 1970s. This was a rather deliberate strategy to counter high Catholic birth rates and strengthen Protestant numbers. Another example would be the elevated birth rates of both Israelis and Palestinians when compared to similar groups – what could be termed ‘competitive breeding’, driven by a group’s desire to reinforce their numbers in a time of conflict.

Soft demographic engineering is when you try and change a population through non-demographic means, such as redrawing boundaries or manipulating cultural or national identities. To take another example from Northern Ireland: when the state was founded, there was a decision to include six rather than nine counties, as those six counties constituted a much more sustainable Protestant-majority population. It was about defining the state in a way that favoured one group over another.

Q: What does the future hold?

A: I use the analogy of three colours: more grey, less white and more green.

Firstly: more grey. Almost every society on the planet is ageing. In many ways, an older global population is a positive thing – it’s definitely more peaceful. But it also raises lots of economic problems, such as a falling working-age population and rising health care costs.

Secondly: less white. The huge expansion in white populations we previously took for granted is now retreating, and historically majority-white countries are becoming much more diverse. Mass migration into Europe and America has changed the face of those continents, and identities will surely continue to shift in these nations over time. Towards the middle of the current century, the percentage of the US population that belongs to minority groups is expected to be more than 50 per cent, and that will surely have an impact. If you look at the ethnic makeup of Trump voters and his slim electoral victory, it’s clear he would not have been elected if America was less white.

At the same time, Africa is about to have a huge population explosion – by 2100, there are very likely to be six or seven times as many Africans as Europeans. We’re in the middle of a massive shift in the global balance. The world is set to become much more African, and it will be very interesting to see how that will affect things.

My last and perhaps most controversial prediction is: more green. The best UN data suggests that by the end of the century, population growth will be slowing towards zero. As the amount of additional agricultural output we need slows, coupled with rising agricultural productivity, there’s an opportunity for nature to take back some space. In countries with declining populations, such as Japan or Bulgaria, you can already find abandoned villages where wolves and bears are returning. So once we reach population stability, we could have a greener world as well.

Q: Should we feel hopeful then?

A: Having said all of this, you never know where things are going – there are always kinks in what we think the pattern is going to be. In 1798, Thomas Malthus described a world in which expanding populations would outstrip food supplies, and everyone would be living on the brink of starvation. But almost exactly as he was writing, the system he so beautifully described was collapsing and we started to see this amazing demographic transition emerge. Likewise, the postwar baby boom caught everyone by surprise. And now we’re living in uncharted waters. Take the rise in acceptance of LGBT+ rights for example – it will be interesting to see what that will mean in terms of demography.

But who knows – we might get a population explosion we didn’t see coming. Or we might all be wiped out by a meteor or plague.

Demography likes to play some funny tricks when you least expect it.


Dr Paul Morland is an associate research fellow at Birkbeck College, University of London, specialising in demography. He is the author of Demographic Engineering: Population Strategies in Ethnic Conflict (Routledge, 2014). His new book, The Human Tide, is his first title intended for a non-academic audience.