According to the UN, it is predicted that the human population could reach ten billion people by the year 2050.

As part of a new BBC Two documentary ‘7.7 Billion People & Counting’, broadcaster and naturalist Chris Packham investigates why our population is growing so rapidly and the impact it is having on our planet in an era of increasing environmental awareness.

Professor Sarah Harper provides an insight into the role of falling birth rates around the world and the impact of an ageing population

7.7 Billion People & Counting is available now on BBC iPlayer

► HORIZON 2020: 1.Chris Packham: 7.7 Billion People & Counting