James Lovelock: The fragility of life on Earth

Stephen Sackur speaks to one of the past century's most influential environmentalists, James Lovelock. He introduced us to the Gaia hypothesis – the idea that our planet and all the life on it are part of one dynamic, self-regulating system. Lovelock is now 101 years old and still having big thoughts about the future of life on Earth. Have we humans sown the seeds of our own destruction?