Fritz Haber

Making ammonia from the nitrogen in the air (1909)

• A 2008 Nature Geoscience study estimated that Haber-Bosch nitrogen fed 48% of the world's population in 2008; a 2023 study put the share at about half in 2019.^[9],[10]
• The same study estimated that synthetic nitrogen made possible about 42% of all births between 1908 and 2008, roughly 4 billion people.^[9],[10]
• Each hectare of cropland went from supporting about 1.9 people in 1908 to 4.3 people in 2008, an increase made possible mainly by Haber-Bosch nitrogen.^[9]
• Beyond ammonia, he devised a glass electrode for measuring how acidic a liquid is, a tool that came into wide use in laboratories.^[2],[7]
• Chaim Weizmann modeled the Daniel Sieff Institute, later the Weizmann Institute of Science, on Haber's Berlin institute after visiting it in 1932.^[5]

Haber's ammonia synthesis is one of the few inventions that changed how many people the planet can feed. Roughly half of humanity now eats food grown with nitrogen made by his method, so we record a large people-fed figure but credit Haber with only 30% of it, because Carl Bosch and BASF engineers did the essential work of turning a benchtop device into an industry. The same chemistry made explosives, and Haber chose to lead Germany's poison-gas effort; we record World War I gas deaths and injuries as harms, with Haber carrying about a third of the responsibility. Some costs resist honest numbers: the munitions his process supplied, which prolonged World War I, nitrogen pollution of rivers, coasts and air, and the example of a leading scientist putting his talent into weapons. His Berlin institute also trained a generation of chemists and physicists, many of whom he helped find jobs abroad after the Nazis forced them out.

FoodEconomyEnvironmentPeaceFundamental science

Each number is the laureate’s credited share of a real-world outcome, cumulative to 2025. The whole outcome, the share of credit, and the reasoning are shown so you can check the arithmetic. Outcomes shared with other laureates are counted once on the impact page.

• Medium confidenceDirectModeledFood

  People whose food depended on Haber-Bosch nitrogen (cumulative births supported)

  1.4–1.6

  billion people fed, credited share

  That is 30% of 4.6–5.2 billion people fed since 1913.

  How this number was built

  Erisman et al. (2008) estimate synthetic nitrogen made possible about 42% of births in 1908-2008 (about 4.0 billion people) and fed 44% of people alive in 2000 and 48% in 2008. Our World in Data reports these, Smil's 40% for 2000, and Rosa & Gabrielli (2023): about half in 2019. No synthetic fertilizer existed before the 1913 Oppau plant. UN births 2009-2025 (OWID): 2.38B. Low: 4.0B x (Smil's 40% / Erisman's 44%) = 3.64B, plus 2009-25 births at 40% = 0.95B; about 4.6B. High: 4.0B + 2.38B x 50% = 1.19B; about 5.2B. Share 0.3: Haber, with Robert Le Rossignol, found the working laboratory method (1909), but Carl Bosch, Alwin Mittasch and BASF did the essential industrial scale-up (Bosch won his own Nobel in 1931), and later engineers kept improving it. Credited: about 1.4-1.6 billion people.^{[7],[9],[10],[11],[14]}

  Sources: Encyclopedia.com; Nature Geoscience; Our World in Data; Our World in Data; BASF

• HarmMedium confidenceDirectSourced totalPeace

  Soldiers killed by chemical weapons in World War I

  31,500–35,000

  deaths caused, credited share

  That is 35% of 90,000–100,000 deaths caused since 1915.

  How this number was built

  The OPCW states that more than 90,000 soldiers died from chemical agents in World War I; Prentiss's 1937 count, cited by Friedrich, is about 90,000. High allows about 10% for undercounting. Share 0.35: Haber persuaded Germany's military to adopt gas, devoted his institute to developing it and oversaw the first chlorine attack at Ypres, so he bears a leading share. The rest lies with German commanders and industry and with the Allied chemists and generals who built their own gas arsenals within months.^[5],[7],[12]

  Sources: Fritz-Haber-Institut der Max-Planck-Gesellschaft; Encyclopedia.com; Organisation for the Prohibition of Chemical Weapons (OPCW)

• HarmMedium confidenceDirectSourced totalPeace

  Soldiers injured by chemical weapons in World War I

  315,000–420,000

  people harmed, credited share

  That is 35% of 900,000–1.2 million people harmed since 1915.

  How this number was built

  The OPCW says close to a million people left World War I battlefields blind, disfigured or with debilitating injuries from chemical weapons (low 0.9 million). Prentiss's widely cited 1937 tally of about 1.3 million gas casualties includes the roughly 90,000 deaths, so non-fatal injuries are at most about 1.3M - 0.09M = 1.2 million (high); historian L. F. Haber judged the usual totals likely too high. Share 0.35, for the same reasons as the gas-death claim: Haber led the German program, but many other decision-makers on both sides share responsibility. Credited: about 315,000-420,000 people injured.^[5],[12]

  Sources: Fritz-Haber-Institut der Max-Planck-Gesellschaft; Organisation for the Prohibition of Chemical Weapons (OPCW)

• Major

  Poison gas: Haber led Germany's chemical-warfare effort

  Haber persuaded Germany's military to test poison gas and oversaw the first large chlorine attack at Ypres on 22 April 1915, when about 167 tons of chlorine were released from some 5,700 cylinders. He believed gas would break the trench stalemate and shorten the war. Instead both sides adopted it, and it added to the suffering without deciding the war. By 1918 chemical weapons had killed more than 90,000 soldiers and injured close to a million more, many of them left blind or disabled.^{[5],[6],[7],[12]}

• Major

  Explosives from air prolonged World War I

  Ammonia is also the starting point for nitric acid, the key ingredient of explosives. When the British blockade cut Germany off from Chilean nitrate, factories using Haber's process filled the gap; in 1918 they produced about 90,000 tons of fixed nitrogen, the main source of nitric acid for German munitions. The Nobel Foundation's biography says this enabled Germany to prolong the war. Haber-Bosch ammonia is still a raw material for explosives today.^{[2],[6],[7],[15]}

• Major

  Secret weapons work and the Zyklon B link

  After 1918 Haber briefly fled to Switzerland fearing war-crimes charges. He then advised covert German chemical-weapons projects in Spain, the Soviet Union and Germany that evaded the Versailles treaty. He also helped found a pesticide company whose cyanide product, Zyklon B, came from an agent his institute had developed during the war. The Nazis later used Zyklon B for mass murder at Auschwitz and other camps; several of Haber's relatives were among the victims.^[5],[7],[8]

• Moderate

  Nitrogen pollution

  Much of the nitrogen spread on fields is never eaten. In the mid-2000s farms used roughly 100 million tonnes of Haber-Bosch nitrogen a year, yet less than a fifth of it ended up in food people ate. The rest leaks into rivers, coasts and air, where it feeds algal blooms, harms wildlife, adds greenhouse gases and forms air pollution.^[9],[15]

• 1892

  Discrimination

  In Imperial Germany a Jewish man could not, in practice, become an army officer in peacetime, and the officer corps and university elite stayed closed or hostile even to many converts. Haber was baptized a Protestant in 1892; historians note that conversion could help an academic career at a time when being Jewish was a handicap.^[7],[8]

• 1933

  Dismissal

  Under the Nazis' April 1933 civil service law, Haber was ordered to dismiss the Jewish scientists at his institute. His war service exempted him, but he resigned in protest on 30 April 1933 and delayed his departure to help colleagues find jobs abroad.^[5],[7],[13]

• 1933

  Persecution

  The Nazi education minister Bernhard Rust declared the regime finished with Haber as a Jew. When colleagues held a memorial for him in 1935, members of the Kaiser Wilhelm Society were officially forbidden to attend.^[5]

• 1933

  Exile

  Haber left Germany in 1933 with severe heart disease, worked briefly at Cambridge at Sir William Pope's invitation, and died in Basel in January 1934 while traveling south.^[2],[5]

• —

  Family killed

  Several members of Haber's family were murdered in Nazi extermination camps.^[5]

Haber was born in Breslau into a well-to-do Jewish family; his parents, Siegfried and Paula Haber, were first cousins. At his secondary school, roughly half the pupils came from Jewish families like his. He identified strongly as German and in 1892 was baptized a Protestant, a common step for ambitious Jewish academics then; he later said he no longer felt ties to the Jewish religion. The Nazis still treated him as Jewish, and in 1933 he resigned rather than dismiss his Jewish staff. In his last months he seriously weighed Chaim Weizmann's invitation to work in Palestine, and his son later gave his private library to the Weizmann Institute.^{[5],[6],[7],[8]}

1. December 9, 1868

   Born in Breslau, Prussia (now Wroclaw, Poland), into a Jewish merchant family; his mother died soon after his birth.^[1],[5]

2. 1891

   Earns his doctorate in chemistry at the University of Berlin after studies in Berlin, Heidelberg and Charlottenburg.^[2],[5]

3. 1892

   Converts from Judaism to Protestant Christianity, at a time when being Jewish could block an academic career.^[7],[8]

4. 1894

   Joins the Technische Hochschule Karlsruhe as an assistant; he becomes professor of physical chemistry there in 1906.^[2],[5]

5. October 13, 1908

   Files his patent on the synthesis of ammonia from its elements.^[9]

6. July 1909

   With Robert Le Rossignol, his tabletop high-pressure apparatus produces a steady flow of ammonia from the nitrogen in air.^[3],[8]

7. 1911

   Becomes founding director of the Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry in Berlin-Dahlem.^[2],[5]

8. 1913

   BASF opens the first ammonia synthesis plant, at Oppau, where Carl Bosch's team scaled up Haber's laboratory method.^[14]

9. April 22, 1915

   Oversees Germany's first large chlorine gas attack, at Ypres in Belgium.^[5],[12]

10. May 1915

    His wife, the chemist Clara Immerwahr, dies by suicide; historians still debate how far his gas work drove her to it.^[5],[6]

11. November 13, 1919

    Named winner of the 1918 Nobel Prize in Chemistry for synthesizing ammonia from its elements; the ceremony follows in Stockholm in June 1920.^[1],[4]

12. April 30, 1933

    Resigns as institute director in protest after being ordered to dismiss his Jewish staff under Nazi law.^[5],[7]

13. 1933

    Leaves Germany and accepts Sir William Pope's invitation to work at Cambridge, England.^[2],[5]

14. January 29, 1934

    Dies of a heart attack in Basel, Switzerland, while traveling south to recover his health.^[1],[2],[5]

1. 1.Fritz Haber - Facts · NobelPrize.org (Nobel Prize Outreach)
2. 2.Fritz Haber - Biographical · NobelPrize.org (from Nobel Lectures, Chemistry 1901-1921, Elsevier, 1966), 1966
3. 3.The Synthesis of Ammonia from Its Elements (Nobel Lecture, 2 June 1920) · NobelPrize.org, 1920
4. 4.The Nobel Prize in Chemistry 1918 - Presentation Speech by A.G. Ekstrand · NobelPrize.org, 1920
5. 5.A brief biography of Fritz Haber (1868-1934), by Bretislav Friedrich · Fritz-Haber-Institut der Max-Planck-Gesellschaft, 2016
6. 6.Fritz Haber · Science History Institute
7. 7.Haber, Fritz (Complete and New Dictionary of Scientific Biography entries) · Encyclopedia.com
8. 8.Fritz Haber: The Damned Scientist, by Magda Dunikowska and Ludwik Turko (Angewandte Chemie International Edition 50, 10050-10062) · arXiv, 2011
9. 9.How a century of ammonia synthesis changed the world, by J.W. Erisman, M.A. Sutton, J. Galloway, Z. Klimont and W. Winiwarter · Nature Geoscience, 2008
10. 10.How many people does synthetic fertilizer feed? · Our World in Data
11. 11.Number of births (UN World Population Prospects data) · Our World in Data
12. 12.History · Organisation for the Prohibition of Chemical Weapons (OPCW)
13. 13.Law for the Restoration of the Professional Civil Service · United States Holocaust Memorial Museum, Holocaust Encyclopedia
14. 14.1913: First Ammonia Synthesis Plant · BASF
15. 15.Transformation of the Nitrogen Cycle: Recent Trends, Questions, and Potential Solutions, by J.N. Galloway et al. (Science 320, 889-892; author copy) · Science / TNO repository, 2008