The Man Who Killed Millions and Saved Billions

The four most common elements in our bodies include nitrogen, which is an essential component of hemoglobin in red blood cells and a central part of our DNA. We obtain nitrogen by consuming plants or animals that have eaten plants, while plants absorb nitrogen from the soil. However, farming on the same soil repeatedly depletes its nitrogen content, leaving insufficient nitrogen for plants to grow. Without adequate nitrogen, plants cannot photosynthesize effectively and become more susceptible to diseases. To address this issue, nitrogen must be replenished in the soil.

Nitrogen is highly abundant, making up 78% of Earth's atmosphere. However, in the atmosphere, nitrogen exists as molecules where two nitrogen atoms are bonded together. As long as these atoms remain bonded, nitrogen is unusable by animals or plants. To make it usable, humans needed to find a way to break these bonds. Naturally, this can happen in two ways. First, lightning, with its immense power, can split nitrogen atoms. The resulting nitrogen reacts with oxygen to form nitrogen oxides, which combine with water droplets and return to Earth. Second, certain types of soil bacteria can break the bonds and convert nitrogen into a form usable by plants. However, bacteria replenish usable nitrogen slowly, and there is not enough lightning to produce sufficient nitrogen. As a result, chemists sought to develop a solution.

In 1811, Georg Hildebrandt attempted to create ammonia by mixing hydrogen and nitrogen in a sealed flask. Ammonia is rich in usable nitrogen, making it highly valuable for agriculture and industry. When his initial experiment failed, he submerged the flask 300 meters underwater to increase the pressure. This attempt also failed, but Hildebrandt was on the right track. The steps he took were scientifically sound, and over the next 100 years, many other chemists would attempt variations of his experiment. However, all of them were unsuccessful.

When Fritz Haber became interested in this problem in 1904, he was stepping into a long history of failed attempts. At the time, Haber was 36 years old and working as a low-level academic at the University of Karlsruhe. He was also a new father to a two-year-old son, Hermann, and married to Clara, one of the first females to earn a PhD in chemistry. Haber dedicated five years to solving the problem. His innovative approach involved combining hydrogen and nitrogen not only at high pressure but also at high temperature, in the presence of a catalyst—a substance that reduces the energy required to break nitrogen bonds. To achieve this, he developed new equipment capable of withstanding the extreme pressure and temperature required for the reaction.

Haber also worked as a technical consultant for a lightbulb manufacturer, giving him access to rare elements like osmium. At the time, only about 100 kilograms of refined osmium existed globally, but the manufacturer was experimenting with using it in lightbulb filaments and held most of the world's supply. Haber suspected osmium would make the perfect catalyst for his experiments, so he brought a sample back to his lab. In 1909, he placed a sheet of osmium in a pressurized chamber, then introduced a mixture of hydrogen and nitrogen under 200 atmospheres of pressure and heated it to 500 degrees Celsius. Under these conditions, the nitrogen bonds broke and reacted with the hydrogen. From the total gas mixture, 6% converted to ammonia. When the mixture condensed, a milliliter of ammonia dripped out, marking a groundbreaking achievement.

Germany's largest chemical company, BASF, commercialized the Haber process. Within four years, they opened a factory in Oppau capable of producing five tons of ammonia daily. This ammonia was used as fertilizer, enabling farmers to produce four times the amount of food on the same plot of land. As a result, the Earth's population quadrupled. There’s a very high chance that you owe your life to Haber’s invention. Today, the planet supports four billion more people than it could without synthetic fertilizers, and approximately 50% of the nitrogen in your body originates from the Haber process.

Haber became a very wealthy man and formed friendships with some of the leading scientists of his time, including Max Planck, Max Born, and Albert Einstein. Everything seemed to be going well—he was highly respected and admired. Then World War I began. During the war, Haber volunteered for military service. However, just a few months into the conflict, Germany began running out of gunpowder and explosives. Ammonia, besides being an excellent fertilizer, is also a key component in explosives. In 1921, one of Haber’s factories exploded. This was due to the immense energy involved in nitrogen chemistry. Just as breaking the bond between two nitrogen atoms requires an extraordinary amount of energy, re-forming that bond releases a similarly immense amount of energy.

Haber converted his ammonia factory into an explosives plant, but this would not be his most controversial decision. In 1914, after witnessing a chemical weapons test, he was unimpressed. Haber believed he could do better, so he set out to create a gas that was deadly in low concentrations and heavier than air, ensuring it would sink into enemy trenches. He established a chemical lab, and within just a few months, he successfully created chlorine gas. In the first attack using this weapon, 5,000 soldiers died. Chlorine gas irritates the lungs, causing them to fill with fluid, so any soldiers who inhaled it effectively drowned on land.

For his contributions to Germany's war efforts, Haber was promoted to captain. Afterward, he returned home to Berlin, where he and his wife, Clara, hosted a gathering that night. When he went to sleep, Clara took his gun and shot herself in the chest. Their 12-year-old son heard the shot and found his mother dead. The next morning, Haber was on a train again, heading to the Eastern Front to supervise a gas attack on the Russian army. Clara's suicide was a result of her husband's obsession with chemical weapons. If you think that her tragic death would have caused Haber to stop working on chemical weapons, you’d be mistaken. During the war, Haber continued his research into chemical weapons. In total, 100,000 soldiers were killed by gas in World War I. However, this number would soon rise dramatically.

When Germany surrendered, Haber was crushed. He had lost most of his money due to hyperinflation. In an attempt to help Germany recover, he tried distilling gold from seawater, but this effort obviously failed. In 1933, the Nazis rose to power, and Haber, who was Jewish, was in danger. The following year, he died of heart failure. After World War I, Haber had developed a cyanide-based, odorless gas called Zyklon B, which he initially intended to use in warfare. To help German soldiers detect the gas, he added extra chemicals to give it a scent. After his death, the Nazis came to his lab and requested that the chemicals be removed to make the gas odorless. A few years later, the Nazis used Zyklon B to kill six million Jews.