The problem isn't absolute population decline. Declining population is good for the planet. The problem is the ratio of old to young. In real world, the popula

The problem isn't absolute population decline. Declining population is good for the planet. The problem is the ratio of old to young. In real world, the population isn't going to decline all of a sudden with declining birth rates. We are first going to have inverted age pyramids. Which means fewer young people will have to support a growing old population. The simplest way to imagine this is imagine you live in a small agrarian village. Your village's ability to feed its old depends on the number of young to hunt/grow crops. If there are fewer young people, there will be lesser food. Who's going to do the backbreaking work of bringing food? Not frail old people for sure. In modern world, this manifests in local manufacturing, local agriculture and local industries. The fewer the local industries (because of fewer young people), the lesser the economic output, the lesser the food (social security) for the old. All this is to say, rapid declines have never been easy for societies and this time is no different.