My guest this week, Leonardo Zangrando, wants to save the oceans and wants to inspire 100 million people to help him do that. Sounds a lot, although given that world population passed 8 billion last year is it really a lot?

The oceans, he tells us, are the lungs of the planet. Forget the tropical rainforests - the oceans are far more significant. Everything, everything we do, affects the oceans. And the oceans affect us.