Along almost every tropical coastline you can find the tangled roots of mangrove trees, a natural barrier against extreme weather. They are also one of the most powerful weapons we have for fighting climate change. Mangrove forests are six times better at capturing carbon than tropical forests. But in the last 40 years up to a third of mangrove forests worldwide have disappeared. Joining presenters Kate Razzell and Qasa Alom to discuss where our mangroves have gone are: Leah Glass, Technical Advisor for Blue Carbon at Blue Ventures Andre Aquino Senior Natural Resources Management Specialist, World Bank, Indonesia Producer: Dearbhail Starr Researchers: Immy Rhodes and Louise Parry Reporter: Fyneface Dumnamene in Nigeria Series producer: Alex Lewis Sound Mix: Tom Brignell Production Co-ordinators: Siobhan Reed and Helena Warwick-Cross Editor: Richard Fenton-Smith