Hell, you can even start pointing at particular bits of science. For example, there would be mass famine without the Haber-Bosch process for ammonia synthesis.
Of course, without this process producing a lot of available nitrogen to use in making explosives during the first half of the 20th century we would probably also have avoided two world wars. Occasional famines and a lower upper-limit on human population or millions dead from guns and bombs... interesting set of choices.
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.
No, 1 billion already-alive humans would have starved to death if not for the green revolution. Malnutrition plays a role in over half of all deaths today. It was even more commonplace before fertilizers and high-yield crop strains.
Eh this is the classic guns kill people vs. people kill people argument. Not having guns or bombs isn't going to stop a war. Some of the bloodiest wars in history were fought using swords and spears.
