World Population Prospects 2019 – good news or bad?

By Jane O’Sullivan

The new United Nations projections for global population tempt complacency by lowering the estimate for growth across this century, but lacks justification for this lower figure. This could perversely counter the UN’s own message that these projections depend in increasing global efforts to ensure “further improvements in access to family planning information and services.”



Last week the United Nations Department of Economic and Social Affairs (DESA) released its biennial report on the world’s population, ‘World Population Prospects 2019’. This should be big news. With so many ecological crises around the world driven by human impacts, it is vital to know how much population growth we need to accommodate, and what prospects there are for minimising it.

What is newsworthy about this release?

  1. Population growth

The estimates of global growth to date are virtually unchanged from two years ago, which is a reprieve from the steady upward revisions we have been used to since 2004. This is best seen by comparing the annual increase in population (Figure 1 – solid lines are historical estimates, dashed lines are projections). As the chart shows, each edition revises not only the future projections but also estimates for the recent past. This highlights the problems of poor data from many countries, which might not have had a census for many years. Pakistan’s last census found 11 million more people than the UN thought they had! The unexpected slow-down in fertility decline since the 1990s meant that growth since 2000 was progressively revised upward – up to this year, which closely matches the 2017 estimates.

Figure 1. Jane
Figure 1. Annual increase in global population to 2100, projected in the UN’s World Population Prospects, 2010 to 2019 editions and in IIASA’s SSP2 scenario (2013)


Since recent estimates are more projection than measurement, we should be a little sceptical about the downturn it presents. It is too early to say whether growth is actually tapering off. The UN has avoided reporting ever-bigger increases each year by revising the past, so that the unexpectedly larger number is spread over more years. The Population Reference Bureau, which also collates international data on population growth, has increased its estimate of global population by more than 90 million per year for the past decade. The Lancet’s massive global study of population and fertility published last November estimated 93 million more people present in 2017 than the UN. When they say that this release “confirms that the world’s population continues to grow, albeit at a slowing rate”, they are referring to the “relative growth rate”, or percentage growth. This has been falling since around 1968, but only because the annual increase (which has risen) is divided by an ever-bigger total population. We should not take false comfort from this.

Despite this lack of change in recent estimates, the projected population for the end of this century (10.9 billion) is down by some 300 million people, and just reaching its peak, whereas the 2015 and 2017 projections reached 11.2 billion with continued growth beyond 2100 (Figure 2). This would be good news if we could trust that it is justified. But there is nothing in the trends to date to suggest that growth is decelerating faster than previously expected.

Figure2 Jane
Figure 2. Gglobal population, projected to 2100 in the UN’s World Population Prospects, 2010 to 2019 editions and in IIASA’s SSP2 scenario (2013)

As can be seen from Figure 3, this steeper deceleration later in the century represents a distinct shift from earlier projections. Up to 2015, an increase in the current estimate resulted in an increase in the projected population for 2100. In 2017, the 2100 population was unchanged, despite recent growth being greater than anticipated. This was achieved by assuming faster fertility decline than in previous revisions. In 2019, the growth rate is falling even faster. This appears to be a purely arbitrary assumption.

Figure2 Jane
Figure 3. Annual increase in global population to 2100, projected in the UN’s World Population Prospects, 2010 to 2019 editions and in IIASA’s SSP2 scenario (2013)

Each of the above figures also shows, in green, the “business as usual” (SSP2) projection generated in 2013 by the Wittgenstein Centre of the International Institute for Applied Systems Analysis (IIASA). This projection is the basis for the climate change socioeconomic scenarios used by the International Panel on Climate Change (IPCC). It is controversially much lower than the UN’s projection. The IIASA defend their rationale as superior to the UN’s, but the above charts should make it clear that history has moved on, and the IPCC’s modellers should do the same. Their work has already demonstrated that higher population scenarios make it very unlikely that we can reduce emissions enough to stay under two degrees of global warming, and to end deforestation. Recognising that we are actually on a higher path should increase priority for population growth reduction.

  1. Fertility

As the UN report says, “Future population growth is highly dependent on the path that future fertility will take.” The report states, “Total fertility has fallen markedly over recent decades” but omits making the more important observation that its fall has virtually stalled in the past decade. From more than one child per woman decline in the 1970s, global fertility fell only 0.1 in the most recent decade. Of course, we would expect it to slow down, as increasing numbers of countries reach below-replacement fertility. But it has slowed more than anticipated, and this is what led to the extra billion added to the expected peak population since the 2010 projections.

It should be noted that fertility could fall in all high-fertility countries, but still rise at the global level. This is because the high-fertility countries are rapidly becoming a bigger share of global population. To stabilise global population, their fertility needs to fall quite fast. Just falling is not enough.

There is good news and bad news on the fertility front. Several countries, where family planning efforts have been ramped up, have declined faster than anticipated in previous UN projections. These include Malawi, Kenya and Timor-Leste. But others, like Rwanda, Ethiopia, Oman and Pakistan, which had shown promising signs of rapid decline, have slowed up. Some have even rebounded to higher fertility, particularly in North Africa and Central Asia.

Remembering that the most recent fertility figures, like the most recent population estimates, are a mixture of measurement and projection, we can take some declines with a grain of salt. As Figure 4 shows, not only future levels (dashed lines) but also the recent past (solid lines) are prone to revision.

Figure 4. Jane
Figure 4. Fertility levels in the Democratic Republic of the Congo and in Pakistan, contrasting the 2010 and 2019 editions of UN’s World Population Prospects

The UN’s medium projection is usually interpreted as the most likely future. But, as the UN stresses in its report, it depends on continued improvement in the provision of family planning:

“The substantial reductions in fertility depicted in the medium variant seem likely to occur if there is continued progress in all facets of development noted above, especially in the least developed countries. Further improvements in access to family planning information and services will enable women and couples to achieve their desired family size, which is likely to continue falling with increased levels of development. If the international community does not follow through on its commitment to ensure that all men and women are informed and have access to safe, effective, affordable and acceptable methods of family planning of their choice, then future fertility declines may occur more slowly, and future population growth may be faster than what is depicted in the medium variant. Conversely, an accelerated expansion in access to family planning information and services could result in a more rapid fertility decline and a smaller global population in the future than projected under the medium variant.”

The biggest determinant of family size is not the availability of family planning, but the parents’ desired family size. The problem is, the UN expects high-fertility countries to experience fertility decline at similar rates to the countries which blazed the trail of family planning in the 1970s and ’80s, but it is relying solely on “increased levels of development” to drive down desired family size. Those earlier family planning countries were much more proactive in promoting the benefits of small families, not merely providing “access to family planning” (as The Overpopulation Project has documented for Indonesia, Iran, South Korea and Costa Rica). This was just as well, because very few countries have actually achieved “increased levels of development” while their fertility remained high. The economic burden of rapid population growth was just too great. But now we have the absurd situation where everything depends on people wanting small families – most of all, the health and security of the parents and children themselves – but nobody is willing to say anything to them that might influence their fertility choices, for fear of this being labelled “coercive”. We are to treat their choices as purely personal, as if they didn’t impinge on the prospects for their children, and the other people and other species who will share the planet with them.

I hope that fertility does fall at least as fast as the UN predicts. But without clear communication to promote small families, access to contraception alone is not guaranteed to bring fertility below the “replacement level” of 2.1 children per woman. As this report shows, a number of countries have stalled or increased their fertility before reaching the replacement level. Some, including Mongolia, Tunisia and Kazakhstan, have rebounded from below-replacement to above. Without explicit motivation to end population growth, the fertility transition remains very uncertain.

  1. The importance of rhetoric

Although presented with a tone of clinical objectivity, the report uses value-laden terms in ways which are unhelpful for motivating greater action to curb population growth. This is particularly true of the press release, whose wording is reproduced in most media reporting of the publication.

When discussing future population growth, the documentation uses language that is carefully neutral, giving no impression whether a higher or lower population is good or bad. Only with reference to the poorest high fertility countries do they say that, “population growth brings additional challenges in the effort to eradicate poverty, achieve greater equality, combat hunger and malnutrition and strengthen the coverage and quality of health and education systems to ensure that no one is left behind.”

Apart from this, the reader would get the impression that population growth is a good thing, or at least that population decline should be avoided. Much of the report is dedicated to documenting the rise in proportions of older people, with strong emphasis that this is problematic, rather than a triumph of the demographic transition, reflecting the astounding achievement that most people born lead long and healthy lives.

The UN’s press release states, “A fertility level of 2.1 births per woman is needed to ensure replacement of generations and avoid population decline over the long run in the absence of immigration” (emphasis added). Could it be that what we really need is to embrace population decline and make the most of its advantages? Would it not be more useful to say, “A fertility level below 2.1 children per woman is needed to avoid ongoing population growth and environmental strains”?

The UN report presents the “demographic dividend” (the economic boost hypothetically attainable due to a higher proportion of working-age people) as “growth of the working-age population” rather than “decline in the proportion of dependent children.” This is problematic, because many governments, particularly in Africa, have been celebrating their youthful, growing populations as an advantage they have over aging Europe. The demographic dividend discourse does not prioritise reaching fertility levels below replacement, and perversely discourages the promotion of small families for fear of population aging.

Yet we read at length about “support ratios” – the ratio of working-age to older and younger people – a metric discredited because it says little about what people actually give and take in terms of social support.

Unmentioned are the many positive effects of aging and declining populations, such as lower resource use, improved employment, cheaper housing and less crime. Instead the focus is on the “unprecedented” ratios of older to younger people, noting, “Falling proportion of working-age population is putting pressure on social protection systems.” Yet no evidence is provided of this pressure, or of the implied fall in the actual workforce. In fact, no developed country has yet experienced a demonstrable shrinkage of workforce due to aging. So far, they have adapted with less unemployment and higher workforce participation, particularly of older workers. It might be postulated that rising proportions of elderly (in contrast to falling proportions of working-age residents) put pressure on social protection systems, but to substantiate this, we should balance increased care needs against decreased spending on infrastructure, housing, education and law enforcement as populations peak and decline. Such balance is not offered.


We should be grateful that the latest UN population report has not revised upward the recent global population estimates. Perhaps fertility decline is finally “getting back on track”. However, we should be sceptical about its downward revision of the global peak population, which does not appear to be supported by evidence. As the publication is intended to advise policy-makers, it is far too heavily focused on demographic aging for my liking, and misses the opportunity to present the end of population growth as a desirable goal.

8 thoughts on “World Population Prospects 2019 – good news or bad?

  1. Thank you for your strong piece. It is even harder to have an opinion about this as a man, as I swear this is now considered a patriarchal issue too. Men influencing in women’s rights. No worry that constantly keeping women pregnant or at home caring for children is a form of control, and that children (and women) have demonstrably better quality of life with few children in the household.
    Finally we are talking about climate change, but the idea that population growth isn’t the clear and main driver of this degradation is Lysenkoism, pure and simple.

  2. I disagree with every person who is writing or who has written in the past about the exploding human population. Humanity has reached the point that is has one and only one choice–coercive population control on a worldwide basis or the collapse of civilization with the deaths of billions, and even the extinction of humanity, in the very near future. Please contact me at and I will send you essays that, in my view, support the position I have taken

  3. Professor Milton Siegel, who for 24 years was the Assistant Director-General of the World Health Organization, speaks to Dr. Stephen Mumford in 1992 to reveal that although there was a consensus that overpopulation was a grave public health threat and would be a major cause of preventable death not too far in the future, the Vatican successfully fought off the incorporation of family planning and birth control into official WHO policy.


    And here is a link to a predictable analysis from the BBC,which mentions, briefly ,a doubling of the human population since 1970, and then goes on to consider the ways in which mass extinctions of our flora and fauna might be averted or stalled, without considering the urgent need for population reduction.

    Politically correct sensitivities are banishing the elephant in the room,as always.

    Thank you for this excellent article; I’ve been an admirer of your work for many years now and I just wish more people would take heed.

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