Sir David Attenborough reveals the findings of one of the most ambitious scientific studies of our time - an investigation into what is happening to our oceans. He looks at whether it is too late to save their remarkable biodiversity. Attenborough explores some of the ways in which we are affecting marine life - from over-fishing to the acidification of sea water. The film also uncovers the disturbing story of how shipping noise is deafening whales and dolphins, affecting their survival in the future.

The world's shipping industry is facing a major challenge. If global shipping were a country it would be the sixth largest producer of greenhouse gas emissions. At current growth rates, if we do nothing, those emissions could double or even triple by 2050. But shipping companies and engineers are creating remarkable new machines to make their industry greener, using a resource that has moved man across the world’s oceans for thousands of years…Wind.