Saving Half the World

In the movie Avengers: Infinity War, Thanos infamously snaps his fingers and (spoiler alert!) half of the life in the universe dies. Thanks a lot, Thanos!

There’s one of those lame, boring processes that I want to tell you about today, but instead of starting in on the process itself, I’m just going to say that it’s like the inverse of what Thanos did, but only for human beings.

The Haber-Bosch Process even has a boring name—maybe Reverse Infinity Snap was taken already—but this incredibly important process gives life to perhaps half of the people alive today.

For centuries, farmers have observed that rotating crops produced much better results than monocropping (growing the same crop in the same place for many years in a row). By the 19th century, the principle that crop growth is limited by the availability of the nutrient in shortest supply was well understood, and this nutrient most often turned out to be nitrogen.

Meanwhile, by the late 19th century, it became evident that a growing world population was putting serious strains on the planet’s ability to feed everyone. Nitrogen was needed.

Natural sources of nitrogen like bat poop (guano) worked great, but they were a drop in the bucket compared to what was needed. Fortunately, there’s a huge source of nitrogen on our planet, all around us: 78% of every breath we take is made of nitrogen.

People knew a way to take nitrogen out of the air, too: you could cool air down until it turned into a liquid, and then you could slowly heat the liquid air up. Each element has a different boiling point, so it was possible to catch them one at a time.

In 1909, Fritz Haber was a chemistry professor working on an idea: Haber wanted to produce ammonia (NH3) by combining nitrogen and hydrogen in an apparatus designed to withstand very high pressures and temperatures. In 1908, he was successful, albeit only at a very tiny scale. It wasn’t economically viable, but it proved that it could be done.

Enter Carl Bosch, the man who could scale the whole thing up. Bosch was a company man at BASF, the enormously important German chemical company. Since extreme pressures and temperatures were needed for the reaction, he set to work on figuring out how this could work at a huge industrial scale.

It turned out that the combination of science and business—of technique and scale—was exactly what was needed. This dynamic duo truly got the job done at a time when things weren’t looking so great for humanity.

When Bosch’s team at BASF got Haber’s blueprints, they immediately began experimenting on a very large scale. Haber had used osmium, which worked well enough, but it was very rare and very expensive. They eventually settled on a much more affordable iron-based catalyst.

BASF then smoothed everything out, making sure the temperature and pressure were ideal to get the most ammonia possible out of the atmosphere. To vastly oversimplify: air went in and ammonia came out.

Let’s get back to that un-snapping of the fingers for a moment.

Prior to 1909, if you had to describe the food situation on Planet Earth, you might have used the word precarious.

Technology’s double-edged sword was the driving force, as we humans finally had the ability to avoid common infections and diseases that shortened human lifespans for time immemorial. Unfortunately, the available food and land was not growing at a similar rate.

At the same time, the lack of arable land meant lots of deforesting to create new space for crops, and intensive farming in fewer locations meant that the fertility of the soil declined over time. The threat of famine was omnipresent, especially in more remote regions.

After 1909, things slowly began to change. As nitrogen-based fertilizers crept out into the market, worldwide crop yields began to eke up until they doubled, and then some. This hasn’t been the only reason we’ve had enough food to feed 8 billion humans—there were loads of technical innovations in the 20th and even in the 21st centuries—but without the Haber-Bosch process, it’s hard to imagine how we could have even gotten started.

Today, scientists and engineers are trying to find a better process than Haber-Bosch. They want to figure out a way that still produces those much-needed fertilizers, but without being so very energy intensive. Today’s process releases nitrous oxide (N2O) back into the atmosphere. Nitrous oxide is about 300 times more damaging to our atmosphere than carbon dioxide.

In addition to other environmental concerns, the engineers would really love to find a more efficient catalyst, and just to improve the process’s overall efficiency. This is likely to be an iterative process for quite some time.

The next time you eat, stop for a moment to think about this process. Consider how scarce food was becoming, and how afraid everyone was of running out. Remember how Haber figured out how to take nitrogen out of the air, and Bosch figured out how to scale the process up.

Finding moments of gratitude within this relative lifetime of luxury is probably one of my favorite things to do. It makes everything taste better.