Their Haber-Bosch process has often been called the most important invention of the 20th century (e.g., V. Smil, Nature 29(415), 1999) as it "detonated the population explosion," driving the world's population from 1.6 billion in 1900 to almost 8 billion today.

The 70 million deaths of World War I and World War II almost vanish next to these numbers. But Haber, a patriotic German Jew, shared some responsibility for those as well: his work helped Germany to significantly prolong WW I, and also to develop the Zyklon B poison gas used in WW II's Holocaust. Haber's almost paradoxical biography affected more lives and deaths than anybody else's.

Bosch was a co-founder of IG-Farben, the world's largest chemical company. After WW II the allies broke it up into three smaller parts, each still larger than any foreign chemical company.