At the start of the Neolithic period – about 9500BC – scientists estimate that species were becoming extinct at a rate of 20-30 per year. Since the population explosion of modern humans, that is estimated to have increased to 20,000-30,000. Most have never been documented by scientists. And in a couple of decades, Wilson reckons this will have increased to 200,000-300,000. Wilson's proposed international initiative, which he has developed with Simon Stuart, the chairman of the Species Survival Commission, would document this species loss and work out how to tackle it.