UN biodiversity summit: 'We need to act substantially and we need to act now' Two weeks after the COP27 wrapped up in Egypt, negotiators are meeting in Montreal, Canada for a UN summit focused on biodiversity. Countries will be setting their targets to protect the world's ecosystems, with the goal of coming up with a Paris-style agreement. It comes as the planet is facing a sixth mass extinction event – one that, as Australian ecologist Mark Burgman explains, humans are responsible for – both because of how and what we consume and how quickly we do so. He joined us for Perspective.