Negotiators from around the world have landed in Montreal, Canada for the UN’s biodiversity conference, Cop15. The summit has been called an “unprecedented” opportunity for turning the tide on nature loss and comes at a critical time: a million species are at risk of extinction and wildlife populations have plunged by an average of 69% between 1970 and 2018. Madeleine Finlay speaks to the director of science at the Royal Botanic Gardens, Kew, Prof Alexandre Antonelli, about the current state of the planet’s biodiversity, what needs to be achieved at Cop15 and how he’s feeling about the possibility of change.. Help support our independent journalism at theguardian.com/sciencepod