Depending on what climate change models you believe, we may already have passed the point at which we can prevent mass death due to a sufficiently large population overusing resources. The only realistic ways to deal with this problem is to get more room and resources by developing technology to send people to live on other planets or wrangle asteroids into orbit and build habitable environments on them. We're already well into this process, but the more people we have and the longer they can live, the more able we'll be to build on these technologies.

Essentially, the problem is already here, and the solution is more people working on it, which preventing people from losing their ability to function would significantly contribute to.