Fertilizer is loaded into a fertilizer spreader from a transfer wagon in Neubukow, Germany. | Bernd Wüstneck/picture alliance via Getty ImagesThe gas prices are unmissable.Since the US and Israel launched strikes on Iran on February 28, Brent crude oil has surged past $100 a barrel for the first time in four years, briefly topping $119 on March 19. California drivers are paying over $5 a gallon, while gasoline prices in Japan hit a record high. The International Energy Agency (IEA) coordinated a release of 400 million barrels from strategic petroleum reserves — the largest in history. Gas station price boards have replaced worried stock traders as the image du jour of economic crisis.So that is the crisis you know about.Here’s one you may not: the Strait of Hormuz, now effectively closed to Western-allied commercial shipping for the third consecutive week, is a key route for more than just oil. It also carries roughly a third of the world’s seaborne fertilizer trade — including nearly half of all global urea exports and 30 percent of ammonia, according to farm sector analysts. These are the chemical building blocks that make our current agricultural system possible. When Iran shut the strait, it didn’t just curtail fuel. It curtailed access to one of the basic components of modern food.“We’re up for a food disaster and all we talk about is gas prices,” Michael Werz, a senior fellow at the Council on Foreign Relations who specializes in food security, told the Atlantic this week.He’s right. And the reason most people don’t see this crisis coming is that most people don’t understand what fossil fuels actually are — and exactly what we really need them for.The chain that keeps us aliveWhen we think about fossil fuels, we think about burning them — in our cars, in power plants, in furnaces. That’s the version of fossil fuel dependence that dominates the public conversation, and it’s the version that the clean energy transition is, gradually, addressing. Renewables now generate more than half of Germany’s electricity, led by solar and wind. Electric vehicles are growing fast. This represents real progress, and it’s one reason why many countries are better equipped to handle this oil crisis than previous ones. But fossil fuels aren’t just fuel. They are, in a quite literal sense, the molecular foundation of modern civilization.If you don’t believe me, ask someone who knows a lot more about this (and about most things, really): the Czech-Canadian scientist Vaclav Smil. Smil, who we named to our Future Perfect 50 list in 2024, has spent decades cataloguing the world’s unexpectedly deep dependence on fossil fuels in books that should be required reading for anyone who wants to understand modern life. In his 2022 How the World Really Works, he identifies four “material pillars” of civilization: cement, steel, plastics, and ammonia. All four require fossil fuels not merely as an energy source but as a basic chemical input without which the production process cannot happen.Ammonia is the one that matters most right now. Through the century-old Haber-Bosch process, natural gas is combined with atmospheric nitrogen at extreme temperatures and pressures to produce ammonia, which is then converted into the nitrogen fertilizers that sustain global agriculture. Smil estimates that roughly half the nitrogen in our bodies comes from this process. In its absence, global agriculture could support perhaps 3 to 4 billion people, far less than the more than 8 billion alive today. The difference today — those 4-plus billion people — is fed, in a very real chemical sense, by fossil fuels.The Persian Gulf is a fertilizer powerhouse — the same abundant natural gas that powers economies around the world also serves as the feedstock for ammonia production. Qatar and Saudi Arabia are major fertilizer exporters, and the wider Gulf region is a critical supplier of urea, ammonia, sulfur, and phosphates. Iranian drones struck QatarEnergy’s facilities early in the war, denting LNG production. Yesterday, its CEO revealed to Reuters that the cumulative damage is far worse than initially understood: 17 percent of Qatar’s LNG export capacity may have been knocked offline for perhaps three to five years. Because that same natural gas is the feedstock for ammonia and fertilizer production, this means the disruption to the global food supply chain will outlast any ceasefire.What has happened is Econ 101. Urea prices have surged since the crisis began, hitting farmers just as spring planting ramps up. That timing matters: fertilizer is one of the biggest variable costs in crop production, and higher prices now could ripple into lower yields and higher food prices later this year.While the world has an architecture of response for an oil crisis like this one — strategic petroleum reserves, bypass pipelines from Saudi Arabia to the Red Sea, naval escort discussions, IEA coordination — almost none of that exists for fertilizer. G7 countries don’t maintain strategic fertilizer reserves. The Saudi bypass pipeline carries crude, not ammonia. A ship captain bold enough to brave the strait under drone fire would choose to carry oil over fertilizer — it’s worth more per ton. Every piece of crisis infrastructure is built to protect the commodity that markets understand and value more. Fertilizer, the commodity that actually feeds people, is an afterthought.Worse, the countries that depend on imported fertilizer most are the ones least equipped to compete for scarce supply. India, which imports more than half its LNG from the Gulf and whose monsoon planting season begins in June, had already seen domestic fertilizer manufacturers cut urea output. Brazil, the world’s largest fertilizer importer, uses sources exposed to disruptions in the Middle East. Sub-Saharan African countries — the ones whose fertilizer use dropped most during the 2022 Ukraine-driven price spike — could once count on foreign aid to fill gaps. With USAID dissolved and most of its functions absorbed elsewhere, that backstop may be gone.Smash it upThis burgeoning crisis demonstrates why diversifying away from fossil fuels and the chokepoints they flow through is so urgent. Many of the countries that have been weathering the situation best — like Spain with its abundant solar buildout — are the ones that invested in alternatives.But the energy transition that’s underway has been, overwhelmingly, an electricity story — and electricity is only about a fifth of global final energy consumption. The things that feed people, move freight, heat buildings, and make materials — the deep physical infrastructure of a globalized planet — remain almost entirely dependent on fossil hydrocarbons. (While countries like the US that have abundant fossil fuel reserves are in a better place, resources like oil and ammonia are priced on a global market, so there’s a limit to how independent anyone can be.) Though in theory you can make ammonia without fossil fuels — use renewable electricity to produce hydrogen, then feed it into the same process — such “green ammonia” is still a rounding error in global production. It is nowhere near the scale that could feed a nation, let alone a planet.The Hormuz crisis has done something rare: It is making the invisible visible. It has shown us, in real time, that modern civilization rests on a molecular foundation most people have never considered — methane turned to ammonia turned to nitrogen turned to food. That foundation is extraordinary. It has enabled the most prosperous era in human history, the feeding of billions who would not otherwise exist. It is something we should celebrate.It is also, as we are learning right now, extraordinarily fragile. The right response to that fragility is to shore up these chains, to diversify through backups and alternatives. Instead, the Trump administration, in its vast carelessness, has chosen to smash it all up, as it has done with so many other precious things. A version of this story originally appeared in the Future Perfect newsletter. Sign up here!