Pulling fertiliser out of the air
The claim is a solution to a specific and pressing supply problem: that atmospheric nitrogen, chemically inert and useless to plants in its gaseous form, could be captured and converted into ammonia, the raw material for nitrogen fertiliser, at a scale large enough to replace the finite natural nitrate deposits agriculture had relied on. Fritz Haber demonstrated the underlying reaction was possible in the laboratory in 1909, combining nitrogen and hydrogen gas under high temperature and pressure over a catalyst to produce a small but steady output of liquid ammonia, working with his assistant Robert Le Rossignol on a bench-scale apparatus rather than anything resembling an industrial plant.
From 125 millilitres an hour to tonnes a day
Turning a laboratory result producing roughly 125 millilitres of ammonia an hour into a viable industry took a separate set of engineering problems, solved by Carl Bosch at the chemical company BASF. Bosch scaled the reaction to industrial pressures and volumes by 1910, working alongside Alwin Mittasch’s discovery of a more practical and economical iron-based catalyst to replace the osmium originally used. BASF began manufacturing ammonia at its Oppau plant in 1913 and had reached an output of twenty tonnes a day within a year, a scale-up that also proved strategically important once the First World War cut Germany off from imported nitrate needed for explosives.
A reaction that still runs the same way
The essential design has held up remarkably well. Modern Haber-Bosch plants still run the same basic reaction, typically at temperatures between 450 and 550 degrees Celsius and pressures of 150 to 250 bar over an iron-based catalyst, converting only about 15 percent of the gas on each single pass but recycling the unreacted portion to reach an overall conversion around 97 to 98 percent. By 2018 global production had reached roughly 230 million tonnes of ammonia annually, with single production lines in modern plants exceeding three thousand tonnes a day, an industrial scale that would have been unrecognisable from Haber’s original bench apparatus.
The cost hidden in the fertiliser bag
That scale carries real, quantified costs. Producing hydrogen for the reaction, mostly by steam reforming natural gas, means the process consumes an estimated 3 to 5 percent of global natural gas supply and 1 to 2 percent of total world energy use, while generating roughly 3 percent of global carbon dioxide emissions in the process. Because nitrogen use efficiency in agriculture typically runs below 50 percent, a large share of the fixed nitrogen never reaches a crop at all, instead running off into waterways where it drives eutrophication and expanding dead zones, contaminates groundwater as nitrate, and escapes as nitrous oxide, itself a significant greenhouse gas.
The same man, a gas attack, and a suicide
The reach of the process beyond agriculture, and the reach of its inventor beyond chemistry, both matter here. Nearly half the nitrogen in human tissue today is estimated to originate from the Haber-Bosch process, food production that has helped sustain a global population that grew from roughly 1.6 billion in 1900 to 7.7 billion by 2018. But the same Fritz Haber who made that possible also led Germany’s wartime chemistry section, developing chlorine gas as a weapon and personally overseeing the first major gas attack at the Second Battle of Ypres in 1915, an assault that produced more than 67,000 casualties. Days after that attack, his wife, chemist and pacifist Clara Immerwahr, took her own life with his service revolver.
Worth sitting with the whole story
This is worth sitting with precisely because it will not resolve into a single clean verdict. The chemistry is genuinely foundational, feeding a share of humanity that would not otherwise be fed at anything like the current global population, and the environmental and moral costs attached to it, both the pollution the process generates and the atrocities its inventor personally directed, are equally well documented rather than speculative additions to the story. Reading about the Haber process honestly means holding both facts at once rather than picking the version that makes for a tidier headline, and that discomfort is exactly what makes the full account more valuable than either half told alone.