The element that feeds the world and arms it — abundant in every breath at 78% of the air, a necessary part of every protein and every strand of DNA, yet locked in its common gas form behind a chemical bond so strong that almost nothing alive can break it. The whole drama of nitrogen is how to force it into a usable form, the line between hunger and plenty, and the chemistry that conjured bread from thin air also conjured the explosives of total war.
Roughly half the nitrogen in your body, on average, was made in a factory. Every protein you are built from needs nitrogen, and the air is four-fifths nitrogen, yet that gas is locked behind a bond so strong that almost nothing alive can break it. For all of history that scarcity was the quiet ceiling on how many people the earth could feed. Then, around 1909, the chemist Fritz Haber learned to pull nitrogen from the air and turn it into fertilizer — bread from thin air — and the population began its climb toward eight billion. The same discovery armed the world. Fixed nitrogen is the basis of modern explosives, so the process that feeds half of humanity also supplied the shells of total war, and Haber himself, the Nobel laureate, went on to direct the first great poison-gas attack.