I am advocating an immediate concentration on slowing down the growth rate of the worlds population and reaching a 0% growth rate in the shortest possible way.
The rate of increase of the world population has been coming down since the 1960’s. We should reach the population peak around 2075 (9 billion people) after which the population will start to decline.
Buckminister Fuller noted that industrialization brought with it a sharp decline in population growth. Presumably, having a dozen children to support you in old age gives way to the social safety net - which is reasonable.
Raising a lot of kids is not easy or all fun. Enjoying your own life, if you are granted that as an option, makes its own friends.