After immersing myself in Henry Gee’s spectacular The Decline and Fall of the Human Empire, I found myself returning to a manuscript I’d read some time ago (no, not Gibbon) but now see with sharpened eyes—Vollset et al.’s landmark 2020 analysis in The Lancet, which forecasts population, fertility, mortality, and migration through the year 2100.
The manuscript, part of the Global Burden of Disease study, offers a nuanced, data-rich counterpoint to the simplistic narrative of unending population growth. While the 20th century was defined by rapid expansion—peaking in 1964, when the global population was growing at an astonishing 3.2% annually, the highest rate in recorded human history—this paper suggests a profound demographic pivot. Our population is projected to peak in 2064 at around 9.7 billion, before entering a long, likely irreversible decline, ending the century with 8.8 billion people globally (95% UI: 6.8–11.8B) .
This moment in 1964—the demographic “apex of acceleration”—now appears to be the hinge point of the Anthropocene. Just as 1969 marked our moonshot moment, 1964 was our peak in planetary fecundity. Since then, global fertility has dropped, and it is predicted to fall well below replacement levels across the majority of nations by mid-century, driven by expanding education for women and increasing access to contraception.
In the reference scenario projected by Vollset et al., more than 150 countries will fall below the replacement threshold (TFR <2.1) by 2050. By 2100, that number is projected to rise to 183 countries. Perhaps most striking: nations such as Japan, Spain, and Thailand may see their populations shrink by over 50%. Even China’s population is projected to halve, with long-term socioeconomic implications, from labor force contraction to eldercare burden .
This resonates deeply with the thesis advanced by Gee: that humanity is not necessarily headed for a cataclysmic fall, but rather a quiet dwindling. Not with a bang, but with a whimper—through “the demographic transition,” which is already baked into the current generation’s reproductive behavior.
If there’s a call to action here, it may be to shift our emphasis from growth toward resilience, from expansion toward sustainability. As our global age structure transforms—with more people over 65 than under 20 by 2100—we will be challenged to reimagine everything from urban design to healthcare, from pension systems to notions of productivity and care.
To quote Gee: “Extinction is the default destiny of all species.” But perhaps, with foresight and compassion, we can script a different kind of decline—graceful, humane, and punctuated by innovation. Let’s work to delay decay, together! Our goal (as we’ve mentioned innumerable times): more hospital-free, activity-rich, dignity-filled days.
Citations:
2. Gee H. The Decline and Fall of the Human Empire.
3. Armstrong, DG, et al, “Repair, Regeneration, and Replacement, Revisited (Redux)”, Diabetes Sci Technol 2025 Mar 15:19322968251326906. Online ahead of print. doi: 10.1177/19322968251326906
