Monday 25 March 2013

Fritz Haber and Carl Bosch

Two German scientists, Fritz Haber and Carl Bosch, devised chlorine gas weapons that were used against French and British troops, in the First World War. Haber’s first wife committed suicide. Then they went on to invent new forms of explosives. During the Second World War, they worked for Hitler, developing a coal based substitute for petroleum that fuelled Nazi planes and trucks.

I had never heard of them until last year. I suspect you, the reader, are reading about them for the first time.

These two men are my heroes - more than Einstien, Salk, Fleming, Bardeen, Rutherford.


In 1900, the world had two billion people. In 2013, it has seven billion. How did this population explosion happen? Why has there been no famine due to food shortage? All famines in the last two hundred years have been because of wars, lack of access or poor administration. Food deficit has NEVER been an issue.

80% of the food humans eat, by weight, comes from only 12 species of plants – rice, wheat, corn, barley, sorghum, soybean, manioc, potato, sweet potato, sugarcane, sugar-beet and banana. They need the right soil and water, but also a vital fertilizing element – nitrogen. The Earth’s atmosphere is 80% nitrogen, but in this form, plants cannot use it. They need something called fixed nitrogen, which is produced by lightning, natural nitrates in the soil, animal dung, decaying plant material and certain legumes.

Crucially, the amount of fixed nitrogen available by these natural processes limits the amount of food crops 
humans can grow, regardless of the land and water available. In the 19th century, this problem was circumvented by expanding the area of land under cultivation and utilizing mountains of guano (bat and bird dung) and saltpeter discovered in South America. Europe imported guano from South America like they imported spices and clothes from India, silk and tea from China and slaves from Africa – in ship loads.

In the twentieth century, these South American supplies ran out. So, nitrogen shortage threatened food supply; unless somebody discovered a way to manufacture artificial fertilizer, using the nitrogen in the atmosphere. This is exactly what Haber and Bosch did. They invented the Haber-Bosch process, ammonia fertilizers, massive factories that would produce them in vast quantities.

They won Nobel prizes for this – Haber in 1920 and Bosch in 1932. France was hunting for Haber as a war criminal, and he was hiding in Switzerland, but after he was awarded the Nobel, France gave up the hunt. For the next decade, France and England used their armies to try to steal the industrial secret that the Haber-Bosch process was; but it was too complex to be copied or stolen and too vital to be destroyed. The great fear was that it not only produced ammonia fertilizer, but also explosives for Hitler’s army.

Today all nitrogen fertilizer is produced by the Haber-Bosch process. Four billion people owe their existence to their invention, but are ignorant that such men lived and what they gave the world.

I will stop here, since it is already three paragraphs more than I planned to write. I read about them in a book called “The Alchemy of Air”, by Thomas Hager. Another excellent resource is Vaclav Smil.


  1. Good to see you started writing again in your blog and equally glad as well for giving us a chance to have a glimpse of your writing.

    Is our Ex Fertilizer central minister (Mr.Alagiri) aware of these people?

    1. I wonder if any minister has heard of them. Or how many bureaucrats.

  2. Comments from PA Krishnan in my Facebook page where I linked to this article, which will be of interest to your readers as well:

    This is a good article, but I don't think Haber was hunted as a war criminal. He won Nobel Prize in Chemistry in the year 1918. Bosch won Nobel Prize in Chemistry for high pressure chemistry and not for this process, if I am not mistaken. Haber was a Jew. And Bosch was the nephew of the other famous Bosch who is the Spark Plug man!

    As an aside, it was the Chinese coolies - around 100,000 of them - who were used in Guano Islands to do the smelly job of collecting bird shit.

    1. Hager's book says that France began a search for Haber, and he took refuge in Switzerland. I cant find independent confirmation.

      Yes, Haber was born a Jew, but converted to Christianity. He was more proud of being German than of being Jewish, so he & his wife converted to Christianity. Apparently this was very common under the Kaiser. But it did not help when Hitler came to power, when he was vilified as a Jew.

      Bosch won the Nobel for a high pressure, large volume, industrial scaling of ammonia manufacture. If spark plug Bosch is more famous, that's a sad comment on history.

  3. Good that i came to know something abt fertilizers. Or else would have just stuck to the thought that fertilizers came from mixing dung, leaves, etc., :p
    A v good informative blog though i am not much of a agriculture related guy.

  4. The fourth sentence "During the Second World War, they worked for Hitler ..." is simply false. Fritz Haber died in Switzerland in 1934. Carl Bosch died in April 1940.

    1. Hitler came to power in 1933. BASF worked to develop explosives and oil from coal for the Nazi government. Bosch was a vital part of BASF then. Hager's book says that Haber escaped to Switzerland because France had searched for him to prosecute as a war criminal.