In moments of "carbon guilt" I've agonized over this too, and ultimately
come to the conclusion--"Hey, it ain't me." For every Vanagon (or RV) there
are, what, 100,000 garden variety commuter cars out there, all forced to
burn millions of barrels of oil on their long commute to work or school or
whatever. The real problem is urban planning or the lack thereof, not the
mpg rating of any one vehicle in particular. Which consumes more petroleum,
one 8 mpg RV or 10,000 hybrids?

As far as birth rate goes, in most industrialized countries it's stagnant or
even negative, as in France. The problem is in the developing world, where
the last thing on people's minds as they...have babies...is their carbon
footprint.

Big questions.