Sir David Attenborough issues climate change warning

Legendary natural history documentary maker Sir David Attenborough has spoken out about the dangers of climate change.

As his latest series, Frozen Planet, comes to a climax, he has warned that the speed of change in the North and South Poles has implications far beyond the polar regions.

Attenborough said that if temperatures continued to rise, it could have a catastrophic effect on the human race.

In an interview with science correspondent David Shukman, Sir David also spoke about what he thought the Earth had left to reveal, his encounter with an amazing frozen caterpillar and about his own experience of visiting the North Pole.