The Haber Process: How the Need For Bombs 100 Years Ago Has Saved Your Life

By Phillip Betts

You may have heard before about a water crisis– the fact that, currently, there simply isn’t enough clean, fresh water to sustain everybody in the world. Despite living on a planet mostly covered in water, so little of it is in a form that we can use for ourselves and our crops that we’ve managed to start running out. However, over a hundred years ago, humanity had an incredibly similar problem, and it was solved by scientist, not looking to save lives, but looking to take them.

You see, in order to survive, plants need nitrogen. Nitrogen is a key component in proteins, as well as in the molecule chlorophyll, both of which are absolutely necessary for plants to survive. And nitrogen is abundant on Earth- the air you’re breathing right now is 78% nitrogen. However, most of the nitrogen on Earth, including that in the atmosphere, is in the form of N2 gas. This form of nitrogen is so prevalent because it’s bonded together with an extremely stable nitrogen-nitrogen triple bond, the second strongest bond that any chemical can make. Due to this, nitrogen gas is almost completely inert, and it is impossible for plants to use this nitrogen in the formation of proteins and chlorophyll.

Now, being smart people, when humans invented agriculture thousands and thousands of years ago, they discovered a way to make their crops grow more efficiently- by spreading animal manure on them. As feces contains fixed nitrogen- nitrogen that can be broken down by plants- in it, these ancient peoples were inadvertently providing their crops with the nitrogen they needed to grow. However, as you may imagine, manure isn’t a very efficient way of providing nitrogen to plants, and as a result, throughout history, famine was inevitable.

By the time the 20th century began, it was known that nitrogen was essential for plant growth, and there were some ways to make sure that fixed nitrogen could be added to fertilizer. The most common way of doing so was harvesting saltpeter, a nitrogen-containing mineral, from caves in Chile and India. This made it possible to effectively manufacture fertilizers, but there began to be concern that the world might run out of these saltpeter deposits. However, there wouldn’t be any real attempt to alleviate this issue until the outbreak of World War 1.

While fixed nitrogen is absolutely necessary in fertilizer, there are two other uses for fixed nitrogen, uses that became incredibly important when World War 1 broke out- gunpowder and bombs. Gunpowder is made partially of saltpeter, as it decomposes under heat to release oxygen. And nitroglycerin, the active component of most explosives of the day, is formed from nitric acid. This became a great issue for Germany, as the world’s large deposits of saltpeter, in Chile and India, were in the hands of their enemies the British. The German leaders began to fear that they would lose the war, not because of anything that took place on the battlefields, but simply because they would run out of gunpowder to fire their weapons with.

As a result, two German chemists, Fritz Haber and Carl Bosch, developed a new method to create usable nitrogen. They found that under intense heat and pressure, hydrogen gas and nitrogen gas could combine to produce ammonia if passed over an iron catalyst. While this process was not able to win the war for the Germans- they managed to snatch defeat from the jaws of victory through diplomatic blunders that led to America joining the war- it did manage to alleviate the possibility of famine in the world. Today, the Haber process, practically unchanged from that developed a century ago, produces 100 million tons of fertilizer every year, and the food supply of 3.5 billion people- half the world’s population- is dependent on synthetic fertilizers created by the Haber process. If you are reading this right now, there is almost a 50% chance that, without the Haber process, you would not be alive right now.

It’s strange to think that something so horrible as a war could be responsible for feeding half of humanity, but I suppose it makes sense. People change when they have to, and people find ways to solve problems when they have to. We have always found ways to overcome our issues, and it gives me hope that we will continue to. The scientific problems of today will be solved, out of necessity, because we always have.