With 78 million new homo sapiens arriving every year, the human race urgently needs to address population growth through debate, Engleman says in his new book, "More: Population, Nature and What Women Want".
Engleman, a programme director at Washington's Worldwatch Institute, spoke to Reuters about how to get the conversation going, and why we need to hurry, but be calm, about it.
Q: Condoms for climate change. Is that what you're saying?
A: At the risk of oversimplifying, it's possible to boil it down to say condoms to help prevent further climate change. The book is very much about relations between human numbers and the environment. And it's very much suggesting that better access to contraception, not just condoms but the whole range, is important in thinking about the environment.
Q: Why is it so hard to talk about this topic?
A: In some ways it is an ultimate taboo. People feel that there is no safe ground - even to bring it up, as an issue, it sounds as though you are telling other people how many children to have, and that is unforgivable as reproduction and having children is so sensitive and so personal.
Q: What are the taboos in this discussion, exactly?
A: Several topics come up that are unpleasant or difficult to deal with, one is abortion, one is immigration, one is racial or ethnic differences in fertility. Mostly northern Caucasian peoples are on average having fewer children than other ethnic groups, or other nationalities. That's not universally true but there's a tendency to perceive it that way. So that makes it even more sensitive. You combine sexuality, abortion, immigration and racial and ethnic differences. What sensitive issue haven't we not thrown into this mix?
