In 1900 the earth's population was about 1.6 billion people, now there are 5.5 billion more. There are 7 billion of us walking around today because we have eaten food which has given us the energy to do awesome things like watch videos on YouTube.

In 1898 a British Chemist, Sir William Crookes, predicted that the earth's population would outpace the supply of wheat by about 1931. Intensive farming was depleting the nitrogen in the soil, raising fears of a global food crisis.

Although nitrogen makes up about 78% of our atmosphere, it exists as an exceedingly stable triple bonded molecule, diatomic nitrogen (or N₂). But for plants to actually have access to the nitrogen to help build themselves, it has to be "fixed", or converted into the more reactive ammonia, which is NH₃.

Before Haber, almost all nitrogen was fixed over hundreds of years by microorganisms in the soil. But rich organic soils were rapidly disappearing. So at that time, most industrialized countries like Germany relied on mined animal manure, particularly bat guano from South America, to make nitrogen based fertilizers.

Yeah, and I should also probably mention that nitrogen, fixed nitrogen, is also extremely useful for creating bombs.

By the early 1900's, Haber was realizing that it was possible  to synthesize ammonia from atmospheric nitrogen and hydrogen, under some specific circumstances.

In 1908, Haber figures out that if you combined atmospheric nitrogen with hydrogen under immense heat, like 500^oC, and immense pressure, like 150-200 atmospheres, circulated over a catalyst like uranium or osmium, it was possible to synthesize ammonia. 

By 1913, the process had been refined and commercialized with the help of a German chemist, Carl Bosch, so that ammonia could be produced on an industrial scale. This Haber-Bosch process, as it became known, is widely considered one of the most significant achievements of the 20th century.

And although the history is murky here, lets just say it doesn't appear that Haber set out to fix nitrogen to stave of world famine. Most believe that he was much more interested in helping Germany make more explosives.

Because while ammonia can be made to produce fertilizer, it can also be easily converted into nitric acid, a very important ingredient for explosives. And as World War I got underway in 1914, the Allies blockaded German ports, cutting off Germany's supply to all those nitrates coming from South America.

Thanks in large part to Haber's invention, Germany was able to continue manufacturing ammunition from synthetic nitrate, and fight on. And fight they did, thanks to another Haber creation.

Haber was appointed director of the Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry in 1911. When World War I broke out, he was recruited to head up Germany's gas warfare division, and he dropped everything for the opportunity.

At this point, Haber put his brilliant chemist's mind to work devising gaseous compounds intended to injure or kill human beings. 

He first came up with a caustic substance called xylyl bromide, made with bromine, but that froze too easily and proved worthless in battle, so he moved onto chlorine and worked on ways to discharge that chlorine gas in enemy trenches.

On April 22nd, 1915, Haber personally oversaw the first large-scale gas attack in military history, in Belgium as German troops attacked French, Canadian, and Algerian troops with more than 150 tons of the poisonous gas. The chlorine gas proved to be horribly effective. The attack resulted in more than 10,000 injuries and deaths, many of those people drowning as fluid built up in their lungs. Blah.

Haber returned to Berlin to throw a dinner party, to celebrate his fantastic new method of killing people in the most horrific and painful way possible, where his wife Clara, a successful chemist in her own right, told him that she could not live with him using their science to create such horrible weapons. Presumably, Haber told her to get out of his grill and mind her own business because that night she shot herself in the chest.

Haber was so shaken by her dramatic action in favor of a more human world that he stopped all work on chemical weapons and no, I'm just kidding, he actually left the following day to oversee a gas attack on the Russian front and continued to supervise Germany's chemical warfare program.

(beeped out swearing)

Always desperate to prove his patriotism he oversaw the development of mustard gas which proved even more effective than chlorine because it was heavy and settled in the trenches. He also helped invent gas masks for German troops after Allied forces began using chemical weapons themselves.

Despite Haber's best efforts, Germany lost that war. You know that, at least I hope you know that, but what you might not know is that in 1919 Haber was awarded the Nobel Prize for Chemistry for "improving the standards of agriculture and the well-being of mankind".

I (beep) you not.

Naturally, this award caused a bit of controversy and if you ever want to see what a white-washed biography looks like go take a look online at the official Nobel Prize write up on Haber, which to this day, devotes all of a half of a sentence to Haber's work on chemical weapons.

Then again, Alfred Nobel is best known as the inventor of dynamite, so maybe it makes sense.

The year after receiving his Nobel Prize, Haber was charged for war crimes but was never prosecuted. Still, Germany's defeat was a crushing blow to him personally, and he vowed to pay off all of Germany's monetary war reparations by himself.

He tried to do it, I (beep) you not once again, by extracting gold from seawater. There's a lot of gold in seawater, its just hard to get out. There's so much sea and there's gold in it, and he was like I can use chemistry!

For six years in the 1920's, with the help of an experimental ship, Haber searched the oceans for bling and he came up pretty much empty handed.

By the early 1930's with Hitler rising to power and anti-semitism growing, Haber could no longer hide his Jewish roots, despite the fact that he was such a tireless proponent of the German cause, he was forced to resign from the Wilhelm Institute in 1933 and was essentially kicked out of the country that he loved so much.

He died in Switzerland, at the age of 65, the following year. 

The story of Fritz Haber does not end there, his inventions and contributions had a continued legacy in the hands of other chemists, and they too are grim.

Earlier in his career, Haber had invented an insecticide, called Zyklon A without any, like, actual goal of killing people this time. It was one of his inventions that he actually didn't want to hurt people with. But it wasn't a particularly notable invention, except that, in the years that followed, German scientists tinkered with the formula to produce a new gas, called Zyklon B.

Specifically, they removed its strong warning odor, and the gas was used in Hitler's concentration camps to kill millions of prisoners during World War II. Among the victims: members of Haber's own family.

As for the nitrogen-fixing process that Haber co-invented, even its benefits are increasingly questionable. Today, factories around the world make over 100 million tons of synthetic nitrogen-based fertilizer every year, and an estimated 2 billion people depend on the Haber Bosch process to grow their food.


But the long term environmental impact of this nitrogen fixing has been kind of frightening. Synthetic fertilizers are chronically overused, and the nitrate runoff from farms around the world is having a devastating impact on water quality.

Runoff from fertilizer sets off explosive growth of algae in waterways and oceans.  As the enormous mats of algae decompose, they suck oxygen from the water, creating enormous "dead zones" where no aquatic life, save a few jellyfish can exist.

Here in the US, the dead zone in the Gulf of Mexico extends to more than 20,000 sq. kilometers each summer, and each year it gets bigger.  The Pew Oceans Commission lists nitrogen fertilizer as the main source of oceanic pollution.

Beyond that, nitrogen fertilizers also release large quantities of nitrogen oxide into the air, a greenhouse gas 300 times more heat-trapping than carbon dioxide.  

Now Fritz Haber couldn't have predicted the environmental impact of the invention that bears his name, but I don't really think he would care.  Creating fertilizer wasn't even his top priority when he set up to capture nitrogen out of the air.  His goal was to keep his country armed for war and he ended up feeding half of the world in the process.

As history reminds us again and again, science isn't good or bad; it's only true.  The people with the best intentions can have the worst impacts and those who only want to kill might end up saving billions of lives.

Science doesn't care.  It's up to us to decide what we do with it.



Thank you for watching this episode of SciShow Great Minds.  If you have some great minds that you would like us to discuss, please tell us in the comments, or on Facebook or Twitter.  We will see you next time.  Goodbye!