Jeff Sachs falls into a trap

You may have heard of Jeffrey Sachs, who is an economist at Columbia, hangs out with Bono, and tries to convince the rich world to spend billions on foreign aid to help Africa and Asia. He claims a big bang aid effort will lift all these people out of poverty. It's generally silly, as we have zero evidence that massive aid does much of anything for anyone.

That might not be so bad, except now Sachs is falling into the old "the world is ending" trap that plagued many people in the 1960's and 1970's. This trap is the "Oh my God, look at all the babies in poor countries. How will the world ever feed all these people, give them electricity, houses, clothes, etc... We MUST be headed for global doom, starvation, and despair." This invariably leads to the proponent of this argument to tell everyone they have to have only 2 kids - or they are dooming society. I won't spend my time debunking this argument (but I'd be happy to if anyone was bored one day), but I noticed this, which is from the NY Times book review:

"In an age when we don’t need to have lots of children to work the fields, or to compensate for high infant mortality, Sachs argues that it’s both economically rational — and crucial for a future of sustainable growth — for people to reproduce at a rate close to 2.1 children per family. In his acknowledgments, Sachs thanks his three children."