The world’s population at the end of the century is confidently predicted to be 8.8bn, but the population will peak at 9.7bn in 2064.


In 1894, the Times newspaper confidently predicted that “in 50 years, every street in London will be buried under nine feet of horse manure”. At the time, London relied on more than 50,000 horses to pull all the Hanson cabs and buses, a number predicted to rise hugely over the next 50 years as businesses expanded. As each horse produced between 15 and 35 pounds of manure per day, you can see how the multiplication and extrapolation produced this extraordinary prediction. London wasn’t the only city to be worried about being buried. Around the world the situation was so dire that when the problem was discussed in 1898 at the world’s first international urban planning conference in New York, no solution could be found. The world was doomed.

Except that it wasn’t.

Within a few years the problem with no apparent solution was solved. The conference had failed to notice that the combustion engine had arrived. All the horses would be replaced by motorised vehicles and the streets of London were saved, except of course from the new problem, pollution!

I always recall the Times’ story whenever I come across new predictions of population changes, which I treat with extreme caution and no little scepticism. Many of these are based on simple Malthusian extrapolations which ignore the human predilection for change. Take fertility rate, for example. The average number of children a woman gives birth to is one of the key factors, perhaps the biggest, in predicting population changes. If the fertility rate is 2.1, the population will be constant. In 1950, women were having an average of 4.7 children in their lifetime, a figure which gave rise to an alarming UN forecast of a world population of more than 17bn by the end of the century. Since then, social progress has led to far more women in education and work. Together with greater access to contraception, this has led to women choosing to have fewer children resulting in a dramatic fall in fertility rate, nearly halving to 2.4 in 2017.

The latest report on population appeared last week in The Lancet journal, and certainly passes the “smell-test” for credibility. Carried out by researchers at the University of Washington’s Institute for Health Metrics and Evaluation, this huge study was funded by the Bill and Melinda Gates Foundation. What impressed was the detailed methodological analysis, covering mortality, fertility and migration. From the mass of information analysed, not only is the world’s population at the end of the century confidently predicted to be 8.8bn, but the population will peak at 9.7bn in 2064. This dramatic reduction from past predictions is due mainly to the average fertility rate falling below 1.7 by the end of the decade. The result will have a “jaw-dropping” impact on societies with a global crash on the number of children being born and many countries having shrinking populations.

Japan’s population, for example, which peaked at 128 million in 2017, is projected to fall to 53 million by the end of the century. Over the same timeframe, Italy will experience a population crash from 61 million to 28. These are just two of the 23 countries, which also include Spain, Portugal, Thailand and South Korea, which are expected to see their populations more than halve. At the other end of the scale, Nigeria’s current population of 206 million will rise to a whopping 790 million by 2100 and not peak until well into the next century, putting enormous strains on the country’s society and infrastructure.

These strains are not only confined to countries with rising populations, they are also experienced by those with dramatically falling numbers. Low fertility rates go hand in hand with ageing populations and a rising tax burden to pay for pensions and healthcare. Here Japan again is an extreme example, with the highest proportion of elderly citizens in the world. With one of the world’s lowest fertility rates, 1.4 in 2016, combined with the highest life expectancy, 88.5 for females, it is experiencing a “super-aging” society in both urban and rural areas. In just 30 years the median age will be 55 and there will be 1.5 working age people for every one elderly person. Contrast this with Nigeria, where the median age is 18.1 years and life expectancy is just 54 years.

India’s neighbour China, currently the most populous country in the world, will peak at 1.4bn in four years’ time, before nearly halving to 732 million by 2100, a drop which will create huge fiscal problems for the government. China’s damaged demographic profile, caused by the “one-child per family” policy, has resulted in a “race to become rich before it gets old”. Beijing is desperately trying to increase fertility rates without success. The marriage age has crept up and women have become more educated and want to work. Having complained about the former policy, couples are now paradoxically restricting themselves to one child because of the prohibitive costs of raising children.

By contrast, India is extremely well positioned and will replace China as the world’s most populous country in 2024. India’s peak population will be 1.6bn and will occur in 2048, before falling back to around 930 million at the turn of the century, still the world’s largest. With live births per woman at an almost perfect 2.2 this year, and a life expectancy of 72 for women, 69 for men, India will benefit from a natural demographic profile, avoiding many of the population pressures experienced by most countries over the next 80 years.

Countries, including the UK, have used immigration to boost their population and compensate for falling birthrates, but this stops being the answer once nearly every country’s population is shrinking. It’s even likely that governments will go from the period when it’s a choice to open borders or not, to frank competition for migrants, as there won’t be enough! India’s self-contained population profile will happily preserve the Lutyens Zone from such problems until at least the end of the century.

John Dobson is a former British diplomat and worked in UK Prime Minister John Major’s office between 1995 and 1998.