Growth, per se, isn't dangerous. Population growth, globally, is inevitable--until less-developed countries become rich enough to make their own way through the demographic transition. And until that transition is achieved climate change is an insolvable problem. What's important is how economic growth is achieved, in both the developed and the developing world. Sustainable growth has to involve using resources more efficiently, and switching to more sustainable forms of energy. Neither of these things will be done by a bunch of old farts collecting their Social Security checks (or its equivalent in other developed economies). It will require a lot of young minds and young workers, which only come through immigration, connecting with capital and education from the developed economies.