From deep inside Gran Chaco, a dry tropical forest in Argentina one and a half times the size of California, comes a wake-up call for the world’s forests. We’ve lost more than a fifth of this incredibly biodiverse region since 1985. And it’s just one of many precious carbon-trapping ecosystems being lost to unrelenting deforestation. Six months ago in Glasgow, world leaders at Cop26 pledged to end and reverse deforestation by 2030. While destruction continues apace in Brazil and the Democratic Republic of the Congo, other countries such as Indonesia offer glimmers of hope. Madeleine Finlay speaks to biodiversity reporter Patrick Greenfield about what his trip to Gran Chaco showed him, what’s at stake around the world, and what’s needed to turn things around. Help support our independent journalism at theguardian.com/sciencepod