Final answer:
Dr. Paul R. Ehrlich predicted massive starvation and social collapse due to overpopulation in the 1970s and 1980s, promoting zero population growth to avert the crisis. Although his predictions were not fully realized, they sparked considerable debate and concern.
Step-by-step explanation:
In 1968, Dr. Paul R. Ehrlich, a Stanford University biologist, published The Population Bomb, which predicted catastrophic scenarios due to overpopulation. He stated, "The battle to feed all of humanity is over. In the 1970s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now." This grim forecast suggested that no efforts would suffice to prevent a significant increase in the world death rate. Though a neo-Malthusian perspective, Ehrlich emphasized environmental factors in the health of the planet's population and promoted the idea of zero population growth (ZPG).
Ehrlich's theories were highly publicized and sparked widespread debate and concern over global overpopulation. However, the extreme social collapse and massive death rates he prophesied did not come to pass as he predicted. Although there were indeed deaths from hunger in the subsequent decades, they did not result in the dramatic population decline or social chaos foreseen by Ehrlich.