The Knowledge Cliff

Executive Summary

The cement industry spends enormous attention on two long-horizon challenges: decarbonization and capital efficiency. Both matter. But there is a third challenge that is nearer, more certain, and far less discussed — and it is arriving on a fixed timetable that no strategy can defer.

The people who know how to run cement plants are retiring, and the demographic pool that would replace them is shrinking at the same time. This is not a forecast. It is arithmetic that is already underway. More than half the world's countries are now below the fertility level needed to replace their populations; the post-war “baby boom” generation is reaching retirement age in record numbers; and across heavy manufacturing, retirements — not growth — are the single largest source of unfilled roles this decade.

For cement, the exposure is unusually acute. Cement plants run on deep, site-specific, largely undocumented expertise — how a particular kiln behaves at the edge of its envelope, which equipment configurations have produced near-misses, which compliance findings were never truly closed. That knowledge lives in a small number of long-tenured people. When they leave, it leaves with them — and the demographic math means there are fewer experienced people coming up behind them to catch it.

1. The Global Demographic Shift

The long demographic transition that began in the wealthy world has now gone global, and it has crossed a threshold that changes the labor math everywhere.

According to the United Nations' World Population Prospects 2024, 131 of 237 countries and areas — 55 percent — now have fertility below the replacement level of 2.1 births per woman. These countries are not a poor-world or rich-world cluster; they span every region and income group, and together they account for 68 percent of the global population. Global average fertility, around five births per woman in the 1950s, has fallen to roughly the replacement level today and continues to decline.

The consequence is already visible in the form of shrinking national populations. The UN estimates that 63 countries — representing 28 percent of the world's population — have already passed their population peak and entered decline. That list is not marginal: it includes China, Germany, Italy, Japan, South Korea, Russia, Spain, and Thailand — many of them major cement-producing and cement-consuming economies.

At the same time, populations are aging. Global life expectancy reached 73.3 years in 2024, up more than eight years since the mid-1990s, and the UN projects that by the late 2050s more than half of all deaths worldwide will occur at age 80 or older. Longer lives at the top and fewer births at the bottom mean the same thing for employers: the ratio of working-age people to dependents is falling, and the supply of new workers entering the labor force is structurally constrained.

The headline is simple. For most of modern industrial history, the assumption was that the next generation of workers would be at least as large as the last. That assumption no longer holds across most of the world.

2. The Retirement Wave Hits Heavy Industry

If declining fertility is the slow-moving denominator, the retirement of the baby-boom generation is the fast-moving numerator — and 2024 through 2027 is its peak.

In the United States, roughly 4.18 million people turned 65 in 2025 — about 11,400 every day — the highest annual figure ever recorded, a moment demographers call “Peak 65.” It is not a single year but a zone: the Alliance for Lifetime Income estimates that more than 4.1 million Americans will turn 65 each year through 2027, and that roughly 30 million boomers will reach traditional retirement age between 2024 and 2030.

The labor-market effect is structural, not cyclical. Analysts estimate that about 1.7 million workers leave the U.S. workforce to retirement each year, which means employers must hire on the order of 142,000 people per month just to keep total employment flat.A large share of what looks like “job growth” is simply replacing people walking out the door.

Manufacturing — cement's category — is among the most exposed sectors. Deloitte and the Manufacturing Institute project that of roughly 3.8 million manufacturing roles that will need to be filled between 2024 and 2033, 2.8 million stem from retirements — the single largest driver — and as many as 1.9 million could go unfilled if the talent gap is not closed. The current workforce is itself aging: the median manufacturing worker is 44.3 years old, and 26 percent of the workforce is already 55 or older. Nearly 60 percent of manufacturers report that attracting and retaining workers is their top business challenge.

The pattern across heavy industry is consistent: the people leaving are the most experienced, the people available to replace them are fewer, and the gap is widest precisely in the skilled, hands-on roles that keep physical plants running.

3. Why Cement Is Acutely Exposed

Every heavy-process industry faces this wave — refining, steel, power, and mining all run on aging, deeply tacit expertise, and cement is not unique in that. What makes cement's version especially acute is the way the work is actually done: continuous, plant-specific, and unforgiving of a wrong call.

The industry is large, physical, and globally distributed. The world produced roughly 4.0 billion tonnes of cement in 2024, a market valued near $410 billion, across more than 3,000 plants worldwide (about 99 in the United States alone). Each integrated plant is a high-complexity facility combining quarrying, high-temperature processing, heavy mechanical systems, and continuous operation. None of that runs on documentation alone.

Cement expertise is unusually tacit.The knowledge that keeps a kiln stable, a mill efficient, and a quality spec on target is largely experiential. An operator who has run a specific kiln for fifteen years knows how it behaves at the edge of its operating envelope, how it responds to a fuel change, and which early signals precede an upset — knowledge that is rarely written down and cannot be transferred in a short handover. The same is true for maintenance technicians who have learned a specific equipment fleet's failure modes, and for safety and compliance staff who carry years of site-specific context in their heads.

That knowledge concentrates in very few people. Precision skills — alignment correction, girth-gear and drive management, refractory judgment, kiln-process troubleshooting — are often held by only one or two people at a given plant. Industry estimates suggest a substantial share of the skilled cement workforce is already over 50 and that a large fraction of experienced technicians will retire before the end of the decade. (These workforce-specific figures are directional industry estimates rather than primary data, but they are consistent with the authoritative manufacturing and demographic numbers above.)

And cement gives expertise nowhere to hide. A kiln runs continuously, around the clock — there is no batch to pause while a newer operator is brought up to speed, and a misjudgment propagates quickly into refractory damage or off-spec clinker. Quality is a real-time act of reading the process and correcting it before it drifts, which is judgment, not a checklist. And because every plant is effectively one of a kind — its own raw materials, fuels, kiln configuration, and history — generic training does not transfer; the expertise that matters is specific to that plant and that equipment. A continuous, plant-specific, high-consequence process is exactly the kind that punishes the loss of experienced judgment fastest.

The combination is the problem. Tacit knowledge, concentrated in a few aging experts, in an industry running continuous high-hazard operations, during the steepest retirement wave on record, while the replacement pool shrinks. Each factor is manageable alone. Together, they describe a cliff — and they are most acute precisely in the precision, process, and safety roles that keep a plant running.

4. The Operational and Business Consequences

The loss of institutional knowledge is not an HR abstraction. It shows up directly in the metrics plant managers are measured on.

• ▸
  Uptime and reliability: When the technician who understood a specific drive train's behavior retires, mean-time-to-repair lengthens, preventive-maintenance discipline erodes, and avoidable failures become more frequent. The cost of an unplanned kiln stop is measured in hours of lost production and tens of thousands of dollars per event.
• ▸
  Safety: The expertise that keeps people safe around real hazards — confined spaces, rotating equipment, extreme heat, combustible dust — is the same expertise that retires. Procedures remain on paper; the judgment that applied them correctly does not.
• ▸
  Compliance: Regulatory knowledge (what a standard requires for a specific configuration, how to prepare for an inspection, which findings recur) is concentrated in long-tenured staff. Its loss raises citation exposure and weakens an organization's ability to defend itself.
• ▸
  Quality and process: Stable clinker and consistent cement depend on operators who can read a process and correct it before it drifts. Newer staff have credentials but not the pattern recognition that comes from years on a specific line.
• ▸
  Succession: Open roles in skilled trades take materially longer to fill than a decade ago, and the people available to fill them increasingly lack the on-site context the role requires.

The through-line is that the plant does not lose a job description when an expert retires. It loses a body of judgment that was never written down — and that judgment was doing more work than the org chart ever credited.

5. You Cannot Hire Your Way Out

The instinctive response is to recruit harder and train faster. Both are necessary. Neither is sufficient, for a structural reason: the labor pool is contracting at the same time demand for experience is spiking.

Below-replacement fertility across two-thirds of the world's population means fewer young workers entering the labor force in absolute terms. The skilled-trades pipeline was already thin; demographic decline makes it thinner. Even where candidates exist, the core asset being lost — decades of accumulated, site-specific judgment — cannot be created by hiring. It can only be developed over years, and the people who would develop it are the ones leaving.

This is why “knowledge transfer” programs that depend on a retiring expert spending a few weeks with a successor consistently fall short. The knowledge is too large, too tacit, and too situational to move in a handover. By the time the gap is obvious — a missed inspection, an extended kiln stop, a near-miss — the person who could have closed it has already gone.

The realistic conclusion is uncomfortable but clarifying: an industry cannot replace what is retiring fast enough, so it must instead capture and systematize that knowledge while the experts are still on site — turning what lives in heads into something retrievable, structured, and available to whoever is on shift.

6. Conclusion: A Knowledge-Capture Problem

The cement industry's demographic exposure is not a question of if— it is already underway, on a fixed timetable, across most of the world's major economies at once. Fertility has fallen below replacement for two-thirds of the global population; the largest retirement wave on record is at its peak through 2027; manufacturing will see millions of experienced workers leave this decade; and cement, which runs on concentrated, tacit, site-specific expertise, is among the most exposed of all.

Reframed correctly, this is not primarily a recruiting problem or a training problem. It is a knowledge-capture problem. The organizations that come through the next decade in the strongest position will be the ones that systematically preserve their institutional knowledge before it retires — converting the judgment of their most experienced people into a durable, accessible asset.

The encouraging part is that this is now achievable in a way it simply was not a few years ago. The same shift in AI that gets most of the headlines also makes it possible, for the first time, to capture tacit operational knowledge and put it to work across the plant — not by replacing experienced people, but by extending their reach and outlasting their retirement. A companion paper, AI Across the Cement Operation, examines exactly how — across safety, compliance, maintenance, and production — and where the limits are.