Fertility rates have dropped sharply since 1990. On average, women today have one less child than 30 years ago. More than half of all countries are now below the replacement rate of 2.1 births per woman — the threshold needed to sustain population size without migration. In many regions, the rate has fallen even further, with some countries averaging fewer than 1.4 births per woman. As populations age and fewer young people enter the workforce, businesses face growing complexity in planning around labor, demand and shifting community structures.

For a long time, population trends were broadly consistent, with slowly decreasing childbearing in higher income countries, and high childbearing across the rest of the globe. Supply chains could be modelled assuming a relatively steady pool of both workers and consumers. But the last few decades have seen a rapid fall in fertility rates, especially in Asia and Europe, an aging population, and competition for skilled migrants. Additionally, climate events are making some areas less viable to live and work in. The combination is pushing demographic volatility to the forefront.

Taken together, these factors are leading to a direct constraint on how supply chains are designed, scaled and staffed. The workforce that companies have historically relied on might not be there in the same way, or in the same places, in the years ahead. The assumptions that once held are now the risk.

Fertility Is Falling — Fast

This isn’t just a developed-market issue. Fertility rates are declining almost everywhere. Even countries like China, India and Brazil that once drove global labor growth are now below replacement. China’s birth rate just hit a record low. And most projections show a steep drop in the working-age population over the next two decades.

That’s not a distant scenario. It’s already reshaping the labor pipeline. For supply chains, this means that the pool of young, physically mobile, entry-level workers is shrinking, and unlikely to return. That matters whether you're running a warehouse, staffing a distribution center or planning for workforce needs two or three years out.

We’re entering an era where labor availability can’t be assumed. It has to be designed for.

People are working longer, and they’re working differently. One in five Americans over 65 is still in the workforce, the highest share in more than 60 years. While many older workers feel they have to remain economically active due to financial concerns, many others remain in the labor force because they wish to. 

One consequence is the need to rethink the design of our working practices, from where we work to how we work, to the very design of our physical working environment. We need new roles, tools and processes that can flex across age, capability and experience.

The companies that figure this out early when it comes to ergonomics, training, workload and design will gain an edge in the new labor market where age diversity isn’t a just a bonus, it’s a given.

Migration as Volatile Safety Valve

In most high-income countries like the U.S., Japan and in Europe, birth rates haven’t been high enough to maintain the working population. But overall numbers haven’t collapsed due to migration. 

For years, immigration has filled the gap — not only to prevent decline, but also to drive growth. It's the reason many labor markets are still functioning. But while migration is positive for workplaces, economies and countries, there are often local tensions around fears over competition for jobs, housing, even marriage partners. Thus, politically, such tensions lead to strain. 

Yet without immigration, populations and workforces shrink, and growth slows. Migration isn’t just a social issue; it’s structural. And for global companies with growing labor and talent requirements, it’s fragile ground to build on.

While birth rates fall across much of the world, Africa is growing. More than half of global population growth between now and 2050 will come from just eight countries — and five of them are in Africa. Nigeria alone is projected to surpass the U.S. in population by 2050.

But growth doesn’t equal readiness. Many of these countries still face major gaps in infrastructure, education and economic stability. That makes it harder to absorb investment at scale, or to plug directly into global labor models.

Africa will play a major role in the next century of trade and logistics. But companies looking to expand or diversify need to understand both the opportunity and the lag. You can’t drop into a new market and expect immediate capacity. You need to start early, build relationships and understand the systems. 

Climate Change as Amplifier

Climate isn’t a separate issue — it’s an accelerant. Heat, floods, fires and water stress are already driving population movement, both within and across borders. That reshapes where people can work, live and build. In some cases, it also reshapes which industries can operate in a region at all.

Climate hazards could significantly reduce labor productivity, disrupt infrastructure and make some regions economically unviable, accelerating both short-term shocks and long-term shifts in where supply chains can operate.

That affects logistics, infrastructure, demand patterns and labor availability all at once. For supply chain leaders, this isn’t about the far-off future. It’s about near-term shocks to regions you may already rely on, and longer-term shifts in where you can viably scale. Designing for climate volatility means understanding that population volatility comes with it.

You can’t predict these shifts with precision. You’re not going to solve volatility with forecasting alone. The answer is adaptability.

Supply chains need to be designed for workforce variability just as they’re designed for demand spikes, inventory shifts and geopolitical risk. That means more simulation. More contingency modeling. More regional flexibility in labor planning. It also means treating labor not as an afterthought, but as a core input into how systems are built, automated, and staffed.

The old question was: How do we optimize this system? The new one is: How do we keep it functioning when the inputs change?

Playbook for Supply Chain Leaders

If population trends are breaking your labor models, the answer isn’t to wait for new models. It’s to intelligently design your future supply chain with new assumptions.

Here’s where to start:

• Model across age bands. Treat age diversity as an input, a bonus, not an exception. Redesign roles and tools to work across physical ability and tenure.
• Build local labor maps. Don’t assume national trends reflect regional realities. Understand where labor is growing, aging, or drying up market by market.
• Pressure-test migration dependencies. If your operations depend on a mobile or immigrant-heavy workforce, model scenarios where that pipeline slows or stalls.
• Rethink automation ROI. In low-growth labor markets, automation isn’t just a cost question. It’s a continuity strategy.
• Simulate climate-population knock-ons. Where climate risk rises, labor volatility often follows. Run population resilience alongside facility resilience.

Designing supply chains for demographic volatility doesn’t mean you’ll always be ahead of it. But if you’re not designing for it at all, you’re already behind.

Don Hicks is the founder and chief executive officer of Optilogic. Sarah Harper is professor of gerontology at the University of Oxford.