A Chicago area reader passes along a Boston Globe Ideas section Q&A in which Stewart Brand, pioneering environmentalist and author of “The Whole Earth Catalog,” sounds the alarm about the dangers of underpopulation. Excerpt:

IDEAS: So as people start to have fewer kids and those kids have fewer kids, you’re expecting that there might be a rapid decline and that this could actually lead to a crisis at some point.
BRAND: Everybody in the world was scared of Japan economically 20 years ago. And one of the reasons they were so powerful was that they were getting the demographic bonus, which is when you start having fewer kids, the parents — or not parents after all — are a lot freer to be productive economically. So you have a youngish generation which is working like hell and not being distracted taking care of kids. And so, you get a boom….But then you pay for it later because the next generation of hard-working kids isn’t there. And as the hard-working generation, that cohort, gets older, they start to move from being productive to being dependent, and there’s not too many people for them to be dependent on, in the younger generation. And then you start to get a nation that looks like Florida.
And that’s why I wind up being mildly pro-natal as an environmentalist, because I think when an economy’s really cracked, you get in a situation where taking care of the environment — the natural infrastructure, as I call it — tends to go down the old priority list. And it sometimes falls right off it.