The closure over the past months of the Strait of Hormuz, through which passes roughly one third of internationally traded fertiliser, choked off a vital artery of the global food system. Modern agriculture is built on synthetic fertilisers, locking farmers into an input-intensive system driven by competition, profit and state support, with rising economic and environmental costs. Nitrogen fertilisers, made with natural gas, underpin around half of global food production. Total global fertiliser use has increased from around 27 million tonnes in 1961 to more than 180 million tonnes by 2023.

When shortages occur, states typically seek to secure supplies rather than reduce dependence. In a deeply unequal global economy, this means the costs of economic and geopolitical conflicts fall disproportionately on poorer states and producers. On top of these costs, poorer countries face major structural obstacles – such as the obligation to service foreign debt in hard currency, which compels reliance on cash crop and mineral export – that make it difficult to significantly alter their position in the wider food system. Therefore, this persistent pattern of crisis management stabilises output in the short term but entrenches inequality and vulnerability.

Much current commentary focuses on restoring fertiliser supply chains – and, implicitly, the agroindustrial systems they sustain. Yet fertiliser crises don’t just disrupt food systems; they reveal and reproduce a global economy in which states compete to secure inputs, deepening structural dependence on them.

Securing supply, reproducing dependence

Fertilisers have long been embedded in imperial circuits of extraction and control. In the 19th century, demand for guano and, later, Chilean nitrates turned parts of Latin America into extractive frontiers supplying European agriculture and, increasingly, munitions production. The development of synthetic nitrogen in the early 20th century cemented this relationship between agriculture and geopolitics.

During the second world war, nitrogen was indispensable to the US production of explosives, among other military uses, therefore much of the country’s synthetic nitrogen production was allocated to wartime industry. As a result, the country imported more than three million tonnes of Chilean nitrate, 90% of which was used to produce fertiliser. These imports helped soften the trade-off between military and civilian needs, enabling simultaneous increases in both agricultural and weapons output.

The 1970s food crisis

The oil shock of 1973-74 triggered a multi-pronged energy, food and fertiliser crisis, as the rise in oil prices fed directly into the cost structure of modern agriculture. Oil prices increased by roughly 300% in the wake of the OPEC embargo, while fertiliser prices nearly tripled. By 1974-75, fertiliser shortages and inflation reinforced one another. What emerged was a long-term structural dynamic: modern agriculture became inseparable from fossil fuel energy, and thus exposed by its disruption.

In the early 1970s, Russian grain production faltered, and Russia secretly turned to the US to purchase the staple in huge volumes. This reduced grain available for sale in the US and the world market, pushing prices up further. In its response to the price shocks and huge demand, US policymakers moved to increase grain output rapidly. Around 62 million acres of land were released from federal set-aside programmes in 1973-74 to boost cereal production. (These programmes had been introduced to manage overproduction crop by paying farmers to remove land from production.)

Across sub-Saharan Africa, governments confronted the same price shock, although from a position of structural dependence on imports and limited fiscal capacity. Governments in Nigeria, Ghana, Tanzania, Cameroon and Mali responded by establishing (or bolstering already-existing) state-led fertiliser distribution systems designed to subsidise access and stabilise production. Such programmes were often organised by state-marketing boards to subsidise prices, control state procurement and distribution and roll out input credit schemes.

These interventions aimed simultaneously to raise agricultural productivity and to shield farmers from volatile world markets. Following structural adjustment programmes in the 1980s, many were dismantled. Nonetheless, the underlying strategy was clear: rather than reducing dependence on synthetic inputs, African states – like their counterparts in the North – sought to secure and extend fertiliser use, embedding it more firmly within national development strategies.

Recent attempts to implement a green revolution in Africa have continued along this path, through increased local production of fertilisers, foreign aid and local governments subsidising fertiliser sales, training local fertiliser traders in how to deploy them. This is despite the fact that agroecological production – multi-cropping using non-chemical fertilisers – has shown the most success in bringing about local food security.

Responses to the current shock

While in many respects the 2026 disruptions are an extension of those triggered by Russia’s 2022 invasion of Ukraine, today’s crisis is both wider and more acute. Geopolitical conflict, energy markets and agricultural inputs have converged into a single global shock.

The effects of the current crisis are uneven. Large agroindustrial producers dominate fertiliser use, but smallholders – less able to absorb price shocks – are more vulnerable. In sub-Saharan Africa, where smallholders produce around 70% of the food supply, reduced access to fertiliser has immediate implications for food security.

State responses to the shock vary: they include export controls, production subsidies and trade restrictions. Yet they are all alike in seeking to secure national access to fertilisers within a constrained global system, at the expense of others. Following the start of the US-Israeli war on Iran, China tightened export controls on key fertilisers, sharply reducing supplies to major importers across Asia and Latin America. In the US, policy focused on expanding domestic production and easing import constraints. Elsewhere, production cuts and export restrictions – from Algeria to Russia and the Gulf – further tightened global supply.

Meanwhile, farmers worldwide are already cutting fertiliser use, switching crops or delaying planting. This is part of what the FAO describes as a broader ‘systemic shock’ to the agrifood system, in which fertiliser shortages intersect with rising fuel costs, mounting debt in poorer countries and the rerouting of land and inputs toward biofuels.

Biofuels divert land from food

Indeed, in response to high oil prices, governments are accelerating the global biofuels push, often under the veneer of the ‘green transition’. Biofuels are produced from readily grown organic materials such as sugar, maize, and oil palm rather than from ancient fossilised matter like coal, oil and gas, which originate from the remains of prehistoric plants and animals. Major agricultural powers including the US, Brazil, India and Indonesia are expanding biofuel programmes, either to reduce their reliance on fossil fuels or to help their firms benefit from rising global biofuel prices. If these policies proceed as planned, global demand for biofuels could increase by around 70% by 2030, drawing on maize, oil palm and sugar crops, redirecting land from food crops.

What is promoted as one part of an energy transition reproduces a deeper tendency within the food system whereby land, inputs and public policy are redirected toward fuel rather than food, reinforcing fertiliser demand and global inequalities.

Turning away?

At its core, the current crisis reflects less a temporary supply shock than a deeper structural contradiction in the global food system. Organised around profit, expansion and resource-intensive production, it cannot easily reduce its dependence on the inputs whose scarcity periodically destabilises it.

The attack on Iran, if – despite fragile peace talks – it continues to disrupt fertiliser supply chains, will compound the crisis. International cooperation will be essential to limiting beggar-thy-neighbour measures; providing financial support to vulnerable countries would also help stabilise production. At present, preventing the shift from food to fuel crops represents a sensible way to stop potentially dangerous reductions in food production. A longer-term solution would require a reorientation of production and consumption. A shift toward plant-based production and consumption would substantially reduce fertiliser demand and release land for ecological recovery. Finally, a substantial share of fertiliser – between one third and over 40% – is used to produce animal feed. This links fertiliser demand directly to the expansion of livestock systems. Efficiency gains and partial substitutions in fertiliser production, animal feed and crop cultivation cannot offset this.

Fertiliser crises past and present reveal not only the fragility of global food systems, but the political choices that sustain them, leaving open the question of whether future responses will once again reproduce dependence, or begin to dismantle it.