Falling fertility rates below replacement (2.1 children per woman) in two-thirds of humanity are driving global population shifts toward depopulation by 2100. UN projections show populations in major economies declining 20-50%, with age structures inverting from pyramids to obelisks: fewer youth, more seniors.
Demographic shifts are transforming population pyramids into shallots or obelisks, with fewer youth and more seniors. The world’s countries are grouped into ten regions: Advanced Asia, Central/Eastern Europe, Emerging Asia, Greater China, India, Latin America/Caribbean, Middle East/North Africa, North America, Sub-Saharan Africa, and Western Europe. In advanced economies, population structures are increasingly top-heavy, resembling obelisks, due to declining fertility and aging populations.
First-wave regions (advanced economies and China) face immediate impacts, with working-age shares dropping from 67% to 59% by 2050. Later-wave regions (emerging Asia, India, Latin America, Middle East/North Africa) peak in the 2030s; Sub-Saharan Africa, the exception, peaks post-2080.
The story of collapsing demographics starts in Luxembourg, the first country the United Nations recorded as having a fertility rate below replacement in 1950, when it first started collecting data.
Luxembourg’s fertility rate rebounded in the 1950s, however, making Serbia and Croatia, both part of Yugoslavia at the time, the first countries where fertility permanently dropped below the replacement threshold, in 1963 and in 1968, respectively. Within a year, fertility rates in Denmark, Finland, and Luxembourg had followed suit. None of these countries has had a fertility rate equal to or above replacement since then.
Twenty years later, most countries in Advanced Asia, Europe, and North America had crossed the replacement fertility threshold.
Subsequently, fertility rates in countries at varying levels of economic development around the world have fallen below replacement—in Thailand in 1989, Mexico in 2015, and India in 2019.
Sub-Saharan Africa is the one region of the world today where fertility rates remain high and are likely to stay above the replacement rate beyond the next quarter century.
Economic
consequences include slowed GDP per capita growth by 0.4% annually on
average in first-wave regions through 2050, unless offset by levers:
doubled-to-quadrupled productivity growth, 1-5 extra weekly work hours
per person, or migration boosting working-age populations. Senior
dependency rises, with support ratios (working-age per senior) falling
from 6.5 globally to 3.9, widening the "senior gap" (consumption minus
income) by 1.3-1.5 times. Public pensions, covering 40-80% of gaps,
strain finances; asset appreciation (e.g., real estate) has supported
seniors but may falter for future generations.
Global Fertility Rate and Annual Population Growth: Top and Bottom 20 Countries in 2025.
Consumption shifts: seniors drive 25% of global spending by 2050 (double 1997), favoring healthcare (up 5-29% per capita) over education (down 4-33%). Labor markets age, with 50+ workers comprising 37% of hours worked in first-wave regions by 2050.
Later-wave regions must "get rich before old," accelerating productivity (median $13/hour vs. $60 in high-income) via investment, human capital, and job creation to capture demographic dividends before they vanish. Two-thirds may not reach high-income thresholds before matching first-wave aging.
Responses: Boost productivity through AI/automation; adapt workforces for seniors via flexible hours, retraining; target senior consumers with tailored products (e.g., adaptive clothing, fall sensors); reform pensions by raising retirement ages; enhance female participation and migration integration. Societies must rethink norms on fertility, caregiving, and intergenerational equity to avert lower growth and eroded wealth flows.