New study shows world pouplation could halve as early as 2064, how would you invest in times of population decline?

We invest because in the long run, stocks only go up. But a lot of this growth comes from a non stop growing world population. What happens if this trend reverses? Global population forecasts have already adapted to more conservative growth projections for the short/mid term future.

A new math based study even finds a worst case scenario where the world's population could halve by 2064. This scenario assumes a major global crisis, for example due to climate change or another major pandemic.

[https://www.sciencedirect.com/science/article/pii/S0960077926006831?via%3Dihub](https://www.sciencedirect.com/science/article/pii/S0960077926006831?via%3Dihub)

Do you think just pumping everything into index funds will still be succesful even when global population plateaus? How could one hedge against declining population?