It's a familiar feature of our oceans and beaches and yet its environmental impact has largely been overlooked. Now supporters say seaweed can help us address climate change by reducing our reliance on fertilisers, and by reducing the methane emissions produced by cows. On top of that, proponents say a new material produced from the sugars in seaweed could provide a biodegradable alternative to the millions of tonnes of single-use plastic we throw away each year. No wonder the World Bank is predicting a global seaweed boom worth $12bn this decade. We hear from scientists and entrepreneurs from Australia to Zanzibar who say we are only just beginning to understand the exciting possibilities posed by this ubiquitous underwater species. The Irish folk tune Dúlamán, about the island’s traditional seaweed gatherers, is used with the permission of musician Seoirse Ó Dochartaigh. Produced and presented by Vivienne Nunis. (Picture: Seaweed farm. Sumbawa. Indonesia. Credit: Getty Images)