Every year the world’s leaders gather for the UN climate change conference, and after a year of record temperatures, this year’s summit has been called the most vital yet. As Cop28 begins in Dubai, Ian Sample hears from Guardian environment editor and resident Cop expert Fiona Harvey. She explains why this summit proved controversial before it even began, what the main talking points will be, and how countries can still collaborate to meet the goals set out in 2015’s Paris agreement. Help support our independent journalism at theguardian.com/sciencepod