Human population has risen from six or seven hundred million in the middle of the eighteenth century to our 6.6 billion today, roughly a tenfold increase. Per capita economic activity -- that is how much each of us on the planet consumes, produces, draws upon natural resources for our sustenance and well-being -- has also risen, as hard as it is to compare over the course of two centuries, roughly tenfold as well..... We don't have to accept the population trends, because people would choose fertility reduction voluntarily in large parts of the developing world, if the alternatives were made available to them. http://www.bbc.co.uk/radio4/reith/