This is the Earth - our planet, home to millions of different species, but only one species dominates everything - human beings. There are nearly seven billion of us living on the Earth, and the human population is increasing by more than two people every second; two hundred thousand people every day; nearly eighty million people every year. Each additional life needs food, energy, water, shelter, and hopefully a whole lot more.

How Many People Can Live on Planet Earth? (BBC Horizon, 2009)