Urea, the most-traded nitrogen fertilizer, cost around $450 per metric ton on February 27, 2026. Three weeks later, it was trading above $700 per metric ton. The figures are from farmdoc daily’s March 17, 2026 analysis of the Hormuz disruption. The shift was not the consequence of a harvest. It was a consequence of the Strait of Hormuz — the twenty-one-mile channel through which roughly thirty percent of internationally traded fertilizer moves — being first closed, then partially reopened, then effectively closed again in the weeks after the February 28 US-Israeli strikes on Iran.
The story is being told, when it is told at all, as a consequence of the war. That is a mistake. The war has exposed a structural condition; it did not create it.
THE CHEMISTRY THE TWENTIETH CENTURY BUILT ITS POPULATION ON
In 1909, in Germany, Fritz Haber demonstrated a laboratory process for fixing atmospheric nitrogen into ammonia under high temperature and pressure. Carl Bosch, at BASF, scaled it. By the time the century ended, the Haber-Bosch process had become the single largest industrial chemistry in existence — consuming roughly one to two percent of global energy and producing the nitrogen from which the food of approximately half of the living human population is now built. The estimate is Vaclav Smil’s, most fully stated in Enriching the Earth (2001) and revised in subsequent work. It has not been meaningfully contested.
What Smil established, with care, is not that synthetic nitrogen is a convenience. It is that the human population at its current level cannot be sustained without it. The limiting nutrient in crop yield, in almost all agricultural soils, is nitrogen. Before synthetic fixation, the global supply was capped by biological processes — legumes, free-living bacteria, lightning — and by the geographic concentration of mineable nitrates, principally in Chile. The population those sources could support was substantially smaller than the eight billion now living.
This is the first fact of the system. It is not news. It is, however, rarely stated plainly when fertilizer prices move.
WHAT THE HORMUZ CLOSURE REVEALS ABOUT THE SUPPLY CHAIN
The second fact is that the chemistry is energy-intensive in a specific way. Natural gas is the feedstock for most ammonia production, and it accounts for between seventy and ninety percent of the variable cost of nitrogen fertilizer. When European TTF gas prices rose in the weeks after February 28, urea production outside the Gulf became less competitive precisely as Gulf production became harder to ship.
The system that feeds half the population now depends on a chemistry produced most cheaply where the gas is cheap, exported most heavily through one of three contested waterways, and supplemented by phosphate and potash from producers structurally prepared to prioritise their own supply over global availability.
The Middle East produces roughly a third of globally traded urea, a quarter of ammonia, and — striking in its concentration — close to half of all internationally traded sulfur, per CRU analyst commentary reported by CNBC on March 25, 2026. Sulfur is the input for phosphate fertilizer. Phosphate, along with nitrogen and potassium, is one of the three macronutrients that cereal agriculture cannot do without.
Three consequences follow. The first is that a disruption in the Gulf, unlike a disruption in any other fertilizer-producing region, hits multiple nutrients simultaneously. The second is that China — the world’s largest phosphate exporter — spent most of 2025 reducing its phosphate exports by eighteen percent and, by late 2025, had effectively banned phosphate exports until at least August 2026 under a dual-track pricing policy administered by the National Development and Reform Commission. That decision was unrelated to the Iran war. It preceded it. The third is that Russia, in response to its own war, has suspended exports of ammonium nitrate. Potash, dominated by Canadian production, has so far held; DAP and MAP have risen more slowly than urea but are both above $700 per metric ton as of mid-March.
WHY THERE IS NO RESERVE
The third fact is that fertilizer has no strategic reserve. Oil has the Strategic Petroleum Reserve; grain has buffer stocks in multiple jurisdictions; fertilizer has neither. It cannot, practically, be stored at scale — urea degrades in humid conditions, ammonia is dangerous to hold in inventory, phosphate products have finite shelf life. The system is built to flow through. When it does not flow, the effect is immediate.
The result is a disruption whose consequences are experienced not during the disruption but one planting cycle later. As of mid-March 2026, the US fertilizer supply was around seventy-five percent of normal. Sixty percent of US corn farmers had secured the nitrogen they needed for the 2026 crop. The other forty percent had not, and many of them were making the decision to plant less corn, or to plant soybeans, which require less nitrogen. These are not emergency decisions. They are rational ones. Their consequences — lower corn supply in the autumn, lower exports, higher global prices — will arrive later in the year and will compound with the analogous decisions being made, right now, in India, Brazil, and East Africa.
WHAT THE FORTY-FIVE MILLION FIGURE ACTUALLY RESTS ON
The UN World Food Programme has estimated that the disruption, if it persists through mid-year, could add 45 million people to the roughly 300 million already facing acute hunger. The figure is a projection, not a forecast. It depends on assumptions about duration, substitution, and remedial distribution. It should be read as indicative rather than precise.
What it actually rests on is a straightforward piece of arithmetic. Nitrogen fertilizer accounts for approximately twenty percent of grain production costs globally. A ten- to twenty-percent reduction in application rates — which is within the range farmers in cost-stressed regions will choose — produces yield declines in a predictable band. The FAO has modelled this repeatedly. Small reductions in application rates produce disproportionate declines in smallholder yield because the fertilizer dose in those regions is already below agronomic optimum. The people most likely to reduce application are the people whose application was already marginal. This is why the forty-five-million estimate concentrates geographically in East Africa and parts of South Asia rather than in the American Midwest.
The Midwest will mostly not go hungry. It will plant less corn and more soybeans; food prices in American grocery stores will rise, visibly enough to enter political speech. The place where the population effect will be unambiguous is the place where the system’s slack was smallest to begin with.
THE DURABLE POINT
The durable point is not that this particular disruption will produce this particular outcome. It is that the Haber-Bosch civilisation — the demographic reality made possible by a century-old chemistry — has never, in the hundred and seventeen years since Haber’s demonstration, developed either a strategic reserve or a supply-chain redundancy commensurate with the population that chemistry now supports. The system has instead grown more concentrated: in fewer producing countries, in fewer export routes, in fewer feedstocks.
The ambition of longevity, understood at the population scale rather than the individual one, is the ambition of keeping human beings alive in the numbers that now exist. That ambition rests on a specific chemistry, a specific energy contract, and a specific set of maritime chokepoints. Each of these is less resilient in 2026 than it was in 2021, and the cost of the nitrogen we need is not paid only in dollars per metric ton.
