The winner of a 1920 Nobel Prize, Haber invented the process of “fixing” nitrogen, or making free-floating nitrogen in the atmosphere usable to grow crops. This vastly increased agricultural productivity and allowed the world’s population to grow since 1900. It has been said that two-fifths of the population would not be alive today without Haber. This development also vastly increased mankind’s reliance on fossil fuel, which became a key component of the man-made fertilizer made possible by Haber. Unfortunately, Haber later collaborated with Hitler to develop chemical weapons for the Nazi war effort, and died in shame.