Live long and prosper?

Inspired by RA's comment on the previous post, I would say it's still an open question what health status and longevity will be like in rich countries like the U.S. of A. as the 21st Century staggers on. It's already conventional wisdom in the public health community that life expectancy will decline a bit because of the obesity epidemic. It's very difficult to say whether there is any signal from chemical exposures, such as pesticides and industrial effluent, for the mildly paradoxical reason that people are living longer. If these exposures do increase the risk of cancer and metabolic diseases, we can't exactly tell because these diseases are also associated with age, and it used to be that not a lot of people lived long enough to get them. Also, obesity is a risk factor, while smoking rates have been declining. Etc. In other words, hard to sort all that out.

But, in fact, probably the biggest threat to our health as a people is the rise in inequality. Inequality makes us sick. If we can't provide decent opportunity, security, and a supportive social environment for everyone, then we won't be as healthy and we won't live as long. Yes, clean air, clean water, a healthful food supply, all matter. But only at the margins. The impact of these sorts of environmental insults on people who are well nourished, psychologically whole, and well cared for, is much less than on people who are otherwise disadvantaged. And disadvantage reproduces itself throughout and across communities, and down through time and generations.

As for the long-term human population, however, it doesn't matter what happens to people past child bearing age. If everybody dropped dead at age 50, it would have no effect on the number of children born in 2050. (At least not directly. It would reduce pressure on resources, obviously, in the interim, but might prove economically costly because we'd lose all those experienced, wise people such as myself.) And actually, the male population barely matters either. The only question is how many girls survive through their reproductive years, and how many babies they have, and how many of those girl babies in turn survive. So unless we want girl babies to die, women need to have fewer children. That's the bottom line.