we're already seeing mass starvation due to global warming
No, we aren't.
Mass starvation was a twentieth century phenomenon, and hunger on that scale hasn't been seen anywhere for thirty years or more - during which time the population in the last place to see a major famine, Ethiopia, has almost quadrupled.
The problem, then and now, that leads directly to large numbers of people suffering from hunger and even starvation, is war.
Not global warming; Not population growth; War.
The key thing that changed at the end of the 1980s, that led to the end of mass starvation, was that the end of the Cold War meant an end to the proxy wars between the Cold War powers that had plagued the third world since the "end" of WWII.