Planet Earth. Leonie Pratt

In a Horizon special, naturalist Sir David Attenborough investigates whether the world is heading for a population crisis. In his lengthy career, Sir David has watched the human population more than double from 2.5 billion in 1950 to nearly seven billion. He reflects on the profound effects of this rapid growth, both on humans and the environment. While much of the projected growth in human population is likely to come from the developing world, it is the lifestyle enjoyed by many in the West that has the most impact on the planet.