Comment by adastra22
Billions. The total carrying capacity of the Earth maxes out at 4bn people, even with maximally optimized agriculture and a vegetarian diet. The extra half of the Earth's population today owe their existence to Haber-Bosch.
It really was a two-man team that discovered nitrogen fixation - the other being not Carl Bosch, but Robert Le Rossignol who assisted Haber in developing his bench-scale nitrogen fixing reactor. Carl Bosch led the team that scaled it up, and that was a large effort of hundreds of people.
Please not that this was in relation to whether or not a general doctor saves lives… A lot of work is indirect.
The Haber–Bosch process was never a two‑man mission to “feed the world.” Haber devised a laboratory method to fix nitrogen, and Bosch led the first industrial‑scale implementation, but neither of them was personally producing, optimizing, transporting, and applying fertilizer across the globe. Turning that reaction into most of the world’s nitrogen fertilizer required teams of chemists, engineers, metalworkers, factory operators, agronomists, logistics workers, and farmers, and an entire century of industrial expansion. If it truly were a two‑person accomplishment, we would only need a handful of farmers per country, which is obviously not how agriculture or industry work.