Part 2 Review of “Empty Planet: The Shock of Global Population Decline”

Empty Planet: The Shock of Global Population Decline claims that (a) life on earth is stressed but coping with the present level of human impact; (b) global population will peak in 2050; (c) subsequent population decline will alleviate ecological problems; and (d) countries with populations that are only slowly growing should act now to boost their population size. Part 1 of this review argued that point (b) is misleading since a peak in 2050, while desirable, would require rapid changes in policy and culture to promote a small “ideal family size” in countries which have high birth rates. Part 2 will explore the book’s other claims, and suggests that even if the population peak does arrive early, their national growth boosting advice would still be unhelpful.

By John McKeown

fig 1.
Figure 1. The book lacks any graph or table but gives numbers for 2050 and 2100, compared here with the UN Medium projection. Source: UN DESA World Population Prospects 2019.

The authors of Empty Planet are Darrell Bricker, the CEO of Ipsos, and John Ibbitson, a leading journalist. For point (a), they grant that “the current population is straining the environment,” but they believe “nothing apocalyptic is on the horizon” (page 32). Combining their forecast of population decline to 7.7 billion by 2100 and their sanguine view that “We’re chugging along with that number right now” (page 44), they foresee only a few decades of strain, followed by relief. That idea could be challenged anthropocentrically by weighing the risk of degrading human welfare, but I will look at a picture bigger than one species. Our impact on wildlife is “apocalyptic” already. For example, the Living Planet Index (LPI), based on four thousand wild vertebrate species (mammals, reptiles, birds, fish, and amphibians), shows that population sizes have on average declined by 60% since 1970.[1] The losses are not evenly spread, and when a species’ population sinks extinction becomes more likely.

The rate at which species have gone extinct over recent decades is many times higher than the background rate. The IUCN Red List (including non-vertebrates, fungi, and plants) identifies the big threats as exploitation (logging, hunting, fishing) and habitat loss (agriculture, housing, tourism, industry); while lesser threats include invasion and disease (often anthropogenic, e.g. ship-borne rats), pollution, fire, climate change, mining, and roads.[2] Impact is not simply proportional to human population since it depends on activity, but neither is it decoupled from human numbers. For example, tropical forest conversion is caused by large-scale commercial agriculture and by subsistence farming, in a 4:3 ratio,[1] and wild plant gathering threatens 557 species.[2] The human enterprise is too large. Lacking an index specifically measuring each country’s impact on wildlife, this review uses the Ecological Footprint which converts a broad range of consumption into a notional land area, the standardised global hectare (gHa).[3] Biocapacity is the footprint that can be sustained long-term. The world footprint is already too big. Also, because many species have small geographical distributions the footprint of each country should not exceed local biocapacity.


For point (c), after 2050, when global population peaks according to Bricker and Ibbitson, the world “will be cleaner, safer, quieter. The oceans will start to heal and the atmosphere cool—or at least stop heating” (page 225). Recovery may take longer than they think. Looking beyond peak population, the authors imagine that “once that decline begins, it will never end” (page 2). Remember, the Empty Planet scenario does not include global catastrophes raising mortality, so decline happens only through persistent low birth rates. They expect a parabola mirroring pre-peak growth. But other possibilities are a plateau, slow decline, or oscillation, because there are forces counter-acting fertility decline. For example, some governments that have experienced natural decrease, or even just a non-growing population, have responded with policies to raise birth rates. Also, evolutionary perspectives challenge never-ending population decline because fertility is between 0.2 and 0.4 heritable.[4] Even without genetics, mechanisms of cultural evolution have an effect, for example birth rate decline is slower in some types of religious group such as the Amish and Hutterites, and high birth rates also appear in new sects inside mainstream religions.[5] Nationally aggregated birth rates do not track variation between groups within a population, and small differences (a fraction of a child) can, over time, change a national population’s composition, leading to more births than forecast. At a global scale, even if in the future most countries have declining populations, one “renegade” country with a higher birth rate can restart global population growth.[6]

For point (d), the authors worry that “small families are hard on an economy” (page 101), because young people are better consumers. Aging is a problem for businesses which gain “tremendous value in hooking a young person on your product” (page 104). They dislike aging because “the young consume … Japan’s economy has been mostly stagnant for going on three decades in part because its aging population consumes less and less” (page 82), which they regard as a bad thing. Bricker and Ibbitson also claim that “it’s hard to innovate when your society is old” (page 83), and ludicrously argue that “the Walkman [1979] represented the peak of Japanese creativity … And it’s been mostly downhill ever since” (page 79). To the contrary, Japan continues to innovate technologically. It also has an opportunity to enhance wellbeing through a “depopulation dividend”.[7] Most countries can improve welfare and prosperity through population shrinkage.

Empty Planet argues that wealthy countries would gain economically if they increased their national birth rates though incentive subsidies (page 71), but the authors warn that because such policies are expensive they will not deliver as many extra people as wanted (page 101). Also their ideals constrain this method because “governments telling women they should have more babies for the sake of the nation seems to us repugnant” (page 239). So they recommend an additional source of people: migration. This weakly affects aging because “migrants aren’t all that young; their median age is thirty-nine” (page 152), and the young become old. But immigration does one thing reliably: it grows a country’s population and, consequently, its total GDP. National power, geopolitical clout on the world stage, is another reason to boost continued growth. “The United States could and should, for its own good, be taking in far more than the one million people who arrive annually” so they advise tripling that to three million new immigrants every year. This would grow the USA to “450 million in 2100 … closing in on a much-diminished China … demographically the American advantage is decisive” (pages 188-9). Immigration added to births “will secure the American hegemony” (page 178), so there is “no reason to believe the twenty-first century will not belong to America” (page 234). However, if consumption in the USA stayed at 8.4 gHa per person,[3] those 450 million Americans would use 3,780 million gHa, exceeding national biocapacity, and demanding 31% of global biocapacity.

Figure 2. Canada population from 1901 with Medium projection to 2068. Sources: Canadian Historical Statistics, StatCan 1983; Quarterly Population Estimates, StatCan 2019; Population Projections for Canada, StatCan 2019.

Canada, while smaller in number than its American neighbour has also grown. Bricker and Ibbitson are Canadian and they hope “Canada’s global standing could improve simply because of the size of its population” (page 235). With current levels of immigration Canada will grow to 52 million by 2060,[8] but the authors mention a goal of growing to 100 million by 2100 (page 208), advocated in Ibbitson’s newspaper, the Globe & Mail. Other wealthy countries “must adopt the Canadian Solution: an immigration level of 1 percent of population annually” (page 209). The authors point out that “Canadians have accepted levels of immigration … decade after decade, that would flummox people in most countries” (page 208). But their chapter explaining why this works well (selection by economic merit and a multiculturalism rooted in dual French-English colonial history) downplays another reason: Canada has a comparatively low population density. Though its population has grown sevenfold since 1900, given its vast 540 million gHa biocapacity (in 2014) there were still 15.2 gHa available per person. The authors suggest Japan is missing a trick by not accepting mass immigration, but Japan’s biocapacity, shared between 126 million people, is only 0.72 gHa per person, or twenty times less than is available for each Canadian.

The future path of global population size will largely be determined by the pace of fertility decline in countries which now have high birth rates. The authors assume that mass emigration has no effect on those countries of origin, but I suspect it has many effects, some negative and some positive. The sum will vary by country, but overall mass emigration slows the pace of fertility decline in the place of origin because it alleviates social status stress. Stress theories build on the observation that mortality decline has preceded fertility decline in onset timing, but the number of years lag varies by country. This theory, that lower child mortality is the cause, mediated by stress mechanisms, of a lower birth rate, can explain the historical cases in which “substantial fertility decline has happened in populations that have not industrialized, urbanized or experienced much economic growth”.[9] When child mortality drops, household size rises, stressing parents and wealth inheritance. Also a larger cohort of young workers competes for relative status.[10] In a multi-phasal response people change their occupation, move to places of opportunity, or reduce births (by delaying marriage, or contraception). Consequently “other things equal, the greater the prospects for out-migration, the later will be the process of fertility decline”.[9]

Empty Planet has minor errors, for example regarding the Philippines’ TFR (Total Fertility Rate) they claim: “Today it’s three, and falling at a rate of about half a baby every five years” (page 52), in the present tense. However, Figure 3 using UN DESA data shows that 0.5 rate of decline belonged to the period 1970-85, not the present. They also write that the Philippines’ total population “is expected to increase from its current level of 101 million to 142 million by 2045, and will then probably start to decline” (page 53). For this they cite a government report, but its first paragraph forecasts that, while the growth rate will slow, population in 2040-45 will be growing at +0.67% annually, and the report’s forecast ends at 2045.[11] The IIASA Medium projection has the Philippines’ population peak around 2075.[12]

Figure 3. Philippines TFR change over five year periods. Source: UN DESA World Population Prospects 2019, using the UN wpp2019 R package.

Empty Planet provides a lively Canadian perspective on global demography, which is useful as a discussion starter. The authors rightly perceive that “the current population is straining the environment, contributing to species extinction and global warming,” and they wisely see that a global population of “eight billion” is “more than enough” (page 32). Bricker and Ibbitson acknowledge that overfishing and pollution harm marine species and their environment, and that “reducing the size of the human population is the best prescription for protecting the seas” (page 229). They also see that the “solution to producing less carbon dioxide might ultimately be producing fewer humans” (page 230). Unfortunately, their ambitions for GDP growth often overwhelm their genuine concern for life on earth.

John McKeown (PhD Liverpool, M.Sc. UWE Bristol) worked at an environmental non-profit for 14 years, and previously at the University of Gloucestershire.


  1. WWF & ZSL. Living Planet Report; 2018.
  2. Maxwell et al. Biodiversity: The ravages of guns, nets and bulldozers. Nature 536 (2016).
  3. Lin, D. et al. National Footprint Accounts. Global Footprint Network; 2018.
  4. Collins, J. & Page, L. The heritability of fertility makes world population stabilization unlikely in the foreseeable future. Evolution and Human Behavior 40 (2019).
  5. Kaufmann, E. Shall the Religious Inherit the Earth: Religion, Demography and Politics in the 21st Century. Profile Books; 2010.
  6. Warren, S. Can human populations be stabilised? Earth’s Future 3 (2015), pp.82-94.
  7. Matanle, P. Japan’s depopulation dividend: searching for an alternative to growth at all costs. The Overpopulation Project; 2018.
  8. Statistics Canada. Canadian Demographics at a Glance, 2nd edition; 2016.
  9. Dyson, T. Population and Development: the Demographic Transition. Zed Books; 2013.
  10. Macunovich, D. Relative cohort size: source of a unifying theory of global fertility transition. Population and Development Review 26 (2000) 235–261.
  11. Philippine Statistics Authority. Highlights of the 2010 Census-Based Population Projections; 2016.
  12. Lutz W., Goujon, A., Samir KC, Stonawski, M., Stilianakis, N. Demographic and Human Capital Scenarios for the 21st Century: 2018 assessment for 201 countries. IIASA; 2018.
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4 thoughts on “Part 2 Review of “Empty Planet: The Shock of Global Population Decline”

  1. Excellent article. But, in my opinion, you give the book (and the authors) much more respect and attention than they deserve. Hit the main fallacies in the core premise, and then stop. Big lies require simple responses.

  2. Thank you Stephen. The book (published by Penguin Random House, and still actively being promoted internationally by authors) has reached a large audience. For example, recently I was at a sustainability conference in the UK and when in conversation I mentioned Population as an issue, the other person responded by telling me about the book Empty Planet.

  3. Do these “Canadians” know why 95% of Canadians live in the southern 5% of the country? And why 5M of us spend half our time in Florida? It’s hell for 10 months of the year! And where will they send these 65 million immigrants – Toronto and Vancouver where you have to be a millionaire to own a condo! We are already fully polluted, thank you.
    Growth at all costs, sounds like cancer.

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