If life expectancy were to increase, where would people live and what would they eat?

Suppose for a moment that medical science made it possible for people to live 25% longer on average – instead of most people dying in their 70s or 80s, the were able to live until age 100 or more.

(Whether that’s desirable for, or desired by, the person is a different question.)

So within a generation or so, world population would move from 7.8 billion (what it is now) to roughly 9.5 billion people.

- where would they all live? We have housing challenges in the US now, and also in the rest of the world.

- what would they eat? Starvation and food distribution are already issues, all over the world and increasingly in the US.

- would social welfare programs (social insurance in most of Europe, Social Security in the US) change to reflect the increased longevity of recipients?