No discussion of environmental policy should ignore the inevitability of an elderly population, but they do.  The interconnectedness of the size of the human population of the planet and the health of global ecosystems is apparent to all, but environmental policy debates treat the population issue as a sideshow, instead of granting it centrality.

Only then can the crucial nature of human population demographics be analysed from an environmental and a cultural perspective.  And from that perspective, there are two ways that nations of the world are coping with the aging of their populations.  One is to import new citizens, the other is to automate society with armies of robots.  These are utterly distinct ways to demographically manage collective aging, and the only sustainable way is to automate - because as humanity achieves zero population growth, eventually every country is going to have an aging population.

In Japan, a nation fully industrialized with a formidable technological base, robots are on the verge of walking, talking, and performing basic tasks.  Parallel progress is being made to render these robots lifelike.  Japan is learning to emerge into the inevitable next state of humankind, because they are not importing young people.  If you believe that human population is destined to level off, then you have to assume the human population will begin to age.

So how Japan copes may help us all prepare for the advancement of humanity to a new evolutionary state, where productivity from semi-autonomous robots and androids removes the need for a young workforce, or a workforce that outnumbers the retirement citizens.  Environmentalists must realize that if our ecosystems benefit from a stable, sustainable quantity of human inhabitants on earth, than inevitably that population will become an elderly population.  How this will work must be part of any comprehensive vision of environmentalism.