Fritz Haber: Plowshares and Swords

The prophet Isaiah wrote of a time when swords would be turned into plowshares. But history reveals that plowshares turn into swords when knowledge used for good becomes knowledge used for evil.

It may be that this solution is not the final one.” With these eerily prescient words Fritz Haber began the conclusion to his acceptance speech for the 1918 Nobel Prize for Chemistry.

As a Nobel laureate, he was honored for developing an affordable method of synthesizing ammonia from hydrogen and nitrogen. A century later, his method remains the industry standard. Vaclav Smil, Distinguished Professor at the University of Manitoba in Winnipeg, explains in his 2001 book Enriching the Earth: Fritz Haber, Carl Bosch, and the Transformation of World Food Production that this was “the most important technical invention of the twentieth century . . . it is the single most important change affecting the world’s population—its expansion from 1.6 billion in 1900 to today’s 6 billion—would not have been possible without the synthesis of ammonia.” Haber’s work made possible the synthetic nitrogen fertilizers that were the catalyst for the Green Revolution, which in turn made possible the massive population growth of the planet in the last century.

Yet Haber also pioneered the development and use of chemical warfare—the first weapon of mass destruction—which has since caused the deaths of untold millions of soldiers and civilians alike.

Incongruity and contradictions were the hallmarks of Haber’s life from his earliest days. He was born on December 9, 1868, in Breslau, Prussia (now Wroclaw, Poland) to first cousins Siegfried and Paula Haber, part of a large Jewish family. His mother died soon afterward due to complications from his birth. His father was devastated. Daniel Charles, author of Master Mind: The Rise and Fall of Fritz Haber, The Nobel Laureate Who Launched the Age of Chemical Warfare, feels this created lifelong tensions between Haber and his father.

Redressing for Success 

These tensions may have played a part in Haber’s decision to pursue higher education instead of apprenticing in the family business, as well as his later conversion to Protestantism. He likely understood that being Jewish, albeit nonobservant, probably kept him from being elected to the coveted reserve officer’s position in the Prussian army, despite passing the related exams after his mandatory military service. After several unsuccessful attempts to enter into a research apprenticeship with Wilhelm Ostwald, a leading physical chemist of the time, Haber was baptized a Protestant in 1892. The timing indicates that his conversion was a move to ensure his future success. 

Haber was soon climbing the ladder of academia at the Fridericiana Technische Hochschule at Karlsruhe. He started as an assistant to a professor of chemical technology in 1894, qualified as a Privatdozent (unsalaried university lecturer) after writing a thesis in 1896 and published a textbook on electrochemistry after a well-received series of lectures in 1898. He became a full professor by 1906, staying until 1911 when he was offered the position of Director of the Institute of Physical and Electrochemistry at Berlin-Dahlem. 

Haber continued his research, focusing on the thermodynamics of gas reactions, which was a pressing problem for Germany as well as the rest of the world. Thomas Malthus had famously alerted the world to the delicate relations between population and food supply in his 1798 warning, “Essay on Population.” A century later, British chemist Sir William Crookes startled the developed world by predicting that the earth’s population would outpace wheat supply by 1931 due to depletion of nitrogen in the soil unless science was able to produce nitrogen—perhaps by extracting it from the atmosphere.

At that time, many countries, including Germany, relied upon imported nitrogen in the form of saltpeter and guano from South America for use as fertilizer and for the production of explosives. But these supplies were dwindling, and the race was on to develop alternatives.

Haber had some early success with synthesizing nitrogen on a small scale, as had other contemporary chemists including Wilhelm Ostwald. But the known processes were prohibitively expensive for mass production. However, Haber found a more affordable way to synthesize ammonia from hydrogen and oxygen using heat and pressure in 1909. Mainly a chemical dye company at the time, Badische Anilin und Soda Fabrik (BASF) sensed the profit-making possibilities and funded further experimentation by two of their top chemical engineers. Carl Bosch and Alwin Mittasch worked with Haber to develop a commercially viable process of fixing atmospheric nitrogen and synthesizing ammonia to make fertilizer. Their successful process, still in use today, is called the Haber-Bosch process. Production began in 1913, and both BASF and the scientists prospered.

Plowshares Into Swords 

The next year saw the outbreak of the Great War. The German government was faced with a shortage of ammunition, and priorities changed. A British naval blockade prevented Germany from importing Chilean saltpeter, essential for the manufacture of explosives. Instead of using synthetic ammonia for fertilizer, the ammonia was now urgently needed to make saltpeter for munitions.

During the war, Haber concentrated on research related to the war effort. He was undoubtedly influenced by the intense patriotic nationalism that swept the country after the unification of Germany in 1871. The forging of the Second Reich was largely the work of another Prussian, Otto von Bismarck, and leaders of the primarily Protestant North German Federation. The resulting nationalistic pride continued through several economic changes and on through the Great War. Like other Germans of the time, Haber’s patriotism formed the basis of his focus and his work.

Despite prohibitions from the Hague conventions of 1899 and 1907, Haber developed chemical gases and argued for their use in warfare. Ever persuasive, he managed to reason around the objections. He supervised the April 1915 chlorine gas attack on French and Algerian troops at Ypres, which resulted in as many as 10,000 painful injuries and deaths. Upon his return, he and Clara Immerwahr, his wife of 18 years, also a chemist and a converted ethnic Jew, had a fierce argument. She had made no secret of her disdain for the use of chemical gases in warfare. That evening, she took his military pistol and shot herself in the chest. Their teenaged son, Hermann, found her as she lay dying. (In 1946, Hermann also committed suicide, and Hermann’s eldest daughter followed suit soon afterward.) Although there was no suicide note, circumstances point to her despair about Fritz’s actions as the catalyst for her suicide. The next morning, Fritz, unable to get a reprieve, left for the Russian front to stage another poison gas attack.

Soon afterward, Haber was appointed chief of Germany’s Chemical Warfare Service and at the age of 46 was finally given his officer position: a rank of captain. He continued to develop more effective methods of gas attacks, often supervising field experiments and narrowly escaping the effects himself. Haber’s second son Ludwig Fritz Haber later wrote in The Poisonous Cloud (1986), “In Haber the OHL [Oberste Heeresleitung or German Supreme Command] found a brilliant mind and an extremely energetic organizer, determined, and possibly also unscrupulous.”

The Great War raged on, undoubtedly lengthened by Haber’s contributions. His synthesis of nitrogen enabled Germany to continue to make explosives after the British cut off the supply of saltpeter from South America. And Haber’s poisoned gas attacks did not end the war. Instead, other countries retaliated by using poison gases in battle as well.

While continuing his wartime work, Haber found time to remarry. His new bride, Charlotte Nathan, was also a converted Jew. Their two children were born within a short time; Eva-Charlotte in 1918 and Ludwig Fritz in 1920.

Search for Neutral Ground 

When the war finally ended, Haber fled to Switzerland to avoid demands of extradition as a war criminal by the Allies. He was granted Swiss citizenship and remained there until, inexplicably, the charges were dropped.

He returned to the Kaiser Wilhelm Institute for Chemistry, where under Haber’s continued direction, the Institute became an internationally well-known center for research, unparalleled in its quality and diversity.

During this time, Haber was nominated for the Nobel Prize for Chemistry. But American, British and French scientists felt his development of chemical weapons and his war criminal status, albeit rescinded, made him an inappropriate choice. (It is no small irony that Alfred Nobel, founder of the Nobel Prizes, gained his fortune from the manufacture of dynamite and other explosives.)

Despite the controversy, Haber accepted the 1918 prize in November of 1919. The presentation speech and his acceptance speech both tactfully avoided any reference to his wartime activities.

Haber quietly continued his work in chemical gases while attempting to extract gold from seawater to help with Germany’s crippling post-war reparations. Six years later, this experiment ultimately failed. His health was also failing and soon his second marriage failed as well, ending in divorce in 1927.

However, his work with chemical gases during this time did prove to be successful. Haber combined a nearly odorless hydrogen cyanide compound with a scented warning agent in a solid yet porous carrier or support. This effective compound, named Zyklon B, was used widely in Germany for disinfection and pest control.

With the rise of Hitler’s regime, ethnic Jews were singled out and increasingly persecuted. Haber, despite his conversion to Protestantism and his immeasurable contributions to science and to Germany, was no exception. In 1933, he was forced to dismiss 12 of his scientists at the Institute, all of Jewish descent. Haber then resigned and fled the country.

Haber seemed broken by the rejection of his country and the lingering controversy surrounding his work with chemical warfare. Yet there was no shortage of offers of employment for Haber. Chaim Weizmann, who later became the first President of Israel, offered him a position at the newly established Daniel Seiff Instiute (now the Weizmann Institute) at Rehovot. He considered relocating to Palestine, but instead accepted an offer to join Sir William Pope at Cambridge, where he stayed for two months.

In England, he was reunited with scientists from his past, some who admired him and some who vilified him. He was never able to live down what he had done to earn the title given him by associates at Karlsruhe: “Father of Chemical Warfare.” This undoubtedly took a toll on his already fragile health. Haber did not fare well during the British winter, so he set off on a trip with no firm destination. He fell ill in Switzerland, and died in Basel on January 29, 1934. There he remains, buried alongside the reburied ashes of Clara.

Final Solution? 

The next world war saw his insecticide, Zyklon B (without its warning scent), become the poison gas of choice for Hitler’s “final solution” and the fatal last gasp of millions of Jews and other minorities including some of his own relatives at Auschwitz-Birkenau.

In retrospect, Haber’s reference to his work in his Nobel Prize acceptance speech, “It may be that this solution is not the final one,” is chilling. Although they seem to point to the Holocaust, these words actually referred to the use of synthetic nitrogen as fertilizer.

Perhaps Haber foresaw the problems caused by the overuse of synthetic nitrogen fertilizers, including dead zones in the oceans and depletion of organic carbon in the soils. Synthetic nitrogen did pave the way for the ubiquitous modern inorganic farming methods of the 20th century—high-yield hybrids and monoculture with pesticides and synthetic fertilizers. Or perhaps he realized that the large quantities of fuel required for his process—coal a century ago, and natural gas today—would not be as abundant and inexpensive as they were in his day, and the rate of consumption could not be sustained.

The conclusion of his Nobel acceptance speech verifies his understanding that, at best, our human efforts are inadequate:

Nitrogen bacteria teach us that Nature, with her sophisticated forms of the chemistry of living matter, still understands and utilizes methods which we do not as yet know how to imitate. Let it suffice that in the meantime improved nitrogen fertilization of the soil brings new nutritive riches to mankind and that the chemical industry comes to the aid of the farmer who, in the good earth, changes stones into bread.” 

We now know that we must find a better way, and that better way may well involve a renewed understanding of the more sustainable ancient ways of crop rotation and fallow. But meanwhile, Vaclav Smil estimates that “the Haber-Bosch synthesis now provides the very means of survival for about 40% of humanity.” That translates to nearly three billion people worldwide who may never have heard of Fritz Haber, yet depend on his discoveries for their lives. 

Haber’s life was marked by tragedy and triumph, often the result of the ethical decisions he made. His work continues to touch the lives of billions on this planet: whether for good or for evil, whether for swords or plowshares.