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100 years of artificial nitrogen – but how many left?

By: Dennis Keeney

I recently was asked in an interview to name the one thing I would change in the world if I had the power to do so. Surprising even myself, I replied quickly “the Haber-Bosch (H-B) process for industrial nitrogen fixation. Imagine – a world without synthetic N! One can imagine the blank look I got when I pulled that one out of the blue.

My response came from a professional lifetime studying the good and bad of fertilizers, especially nitrogen. And it comes from much reading of the literature on food production and the ills of our advanced society. So, bear with me as I look into a reverse crystal ball for what-if, realizing all the while that there is no way of going back, but examining whether the reverse crystal ball could help us move forward.

Much of my background material comes from Vaclav Smil’s book, Enriching the Earth: Fritz Haber, Carl Bosch and The Transformation of World Food Production (2001), sprinkled in with Smil’s Feeding the World: A Challenge for the Twenty-First Century (2000) and L.T. Evans’s Feeding the Ten Billion: Plants and Population Growth (1998). There are many other books and papers I could cite, but most are repeating much of the same material.

So, what is the H-B process anyway, and how did it come about? A bit of history:

The world, especially Europe and China, had gained population in bursts, but around 1500 farming moved from subsistence to commercial. Farmers owned their land and developed cropping rotations centered on increasing carrying capacity for animals with fertility supplied through manures and nitrogen coming from clover. Soon, high-yielding cereals were introduced and population headed toward the first billion.

In 1798 Thomas Robert Malthus published “Essay on the Principle of Population,” in which he stated that while population increases geometrically, food supply increases arithmetically, concluding that at some time the world will run out of food. The essay is as important as that of Darwin’s on evolution, and both remain true, even though Malthus is derided today. Synthetic nitrogen fertilizer delayed Malthus’s prediction by probably 300 years, but not forever.

The world population gained its second billion from 1825 to 1927, and science began its role in food production. Varietal improvement through selection, mechanization, and better crop and animal husbandry kept up with food demand. By 1850 the first commercial nitrogen fertilizers, largely bird guano from Chile and Peru, were being used to increase grain yields. But by the end of that century it became apparent that these supplies were limited. Since nitrogen compounds were also immediately needed for explosives, it was imperative that someone quickly discover a way to synthesize compounds from atmospheric nitrogen. Otherwise Germany would lose World War I.

Fritz Haber, a German, applied earlier research on gas equilibria to ammonia synthesis, and his successes attracted the support of the chemical giant BASF. The process was patented on June 8, 1911, exactly a century ago. Carl Bosch, a metallurgist, was indispensable in putting together the catalysts and management expertise to make the synthesis commercially viable. The two shared the Nobel Prize for their invention. The first commercial plant, built in central Germany, away from Allied Forces’ air strikes, went into production in April 1917. But most of the nitrogen went to the war effort, delaying the end of WWI.

World War II slowed the expansion of fertilizer production, and it was not until the 1950s, when the United States ramped up production, that nitrogen fertilizer use became widespread. This was when the world population reached 3 billion.

What if the H-B process had not been technically feasible, or prohibitively expensive and energy consuming? First, we would not have had so much of the horrendous wars, shootings, street gangs and all the other ills associated with explosives. Not that there would not always have been killing, as proven by human behavior before H-B, and saltpeter (sodium nitrate) was available in sufficient quantities to keep the guns firing. And there were alternate ways, albeit expensive, to produce fixed nitrogen.

But what about agricultural production? Let’s assume the 3 billion in 1950, before synthetic nitrogen fertilizers led to spectacular grain-yield increases, was the world’s carrying capacity. Allowing for the slow progress in crop breeding, especially grains but also forages, perhaps the world could feed 4 billion in a steady state. Realizing this fact, civilization could work toward stabilizing the population, developing a world model different from capitalism.

Oil reserves would have lasted far longer with the fewer people on the road, air pollution would be less, and anthropogenic global warming probably would be a lesser threat. Cities and farms would be smaller, and the self-contained and managed farm (family farm) would be the norm, not the exception. Without grain surpluses, large confinement operations could not exist. Soil erosion would be controlled with the perennial-grain rotations that would be common. Soils would be healthy.
Food would be healthy, too. Rotations require minimal pesticide use, and without confinement feeding antibiotics would have no use on the farm. What we now call organic food would be just normal food.

Alas, this idyllic world is not to be, at least not now. But there is no assurance that, sometime in the future, fossil fuels will not be so scarce that the manufacture of anhydrous ammonia becomes prohibitively expensive.

There are a few research groups out there thinking of this scenario. Unfortunately, they tend to get drowned out by the “feed the world” chorus that says we must maximize production and develop an intensive sustainable agriculture.

These slogans will dim when nitrogen fertilizers again become truly limiting. And that will happen sometime.

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