You don't get to claim the entirety of the green revolution here, and most of those 1 billion would not have been born in the first place if the Harber-Bosch process did not exist. If we are going to go to that particular level of sophistry then I would add the four generations of descendants from WWI deaths and three generations of WWII/Stalin-induced famines/Great Leap forward deaths, etc. Playing alternate history speculation is interesting, but trying to project any particular distance beyond the immediate point in question is a fools errand.