The COP30 climate summit is taking place in the Brazilian city of Belém, a gateway to the Amazon rainforest, which continues to face widespread deforestation. We all know that our climate is changing and that we are largely responsible for this, but we can’t tackle the problem unless we understand what’s going on.

One scientist who’s done more than most to rectify this is Professor Pierre Friedlingstein. He’s a prominent climate scientist and Chair in Mathematical Modelling of the Climate System at Exeter University. His models have transformed our understanding of climate change, revealing a complex dynamical system with carbon at its centre, cycling between the atmosphere, oceans and land, to directly influence the level of carbon dioxide in the atmosphere.

Pierre is actively involved in assessing the state of our climate through the Intergovernmental Panel on Climate Change and, as director of the Global Carbon Budget, estimates the remaining amount of carbon dioxide that can be emitted before we breach our global climate targets. It’s the ultimate test of effective climate action and the latest annual update will be released at COP.

Pierre explains how we can all play our part to reduce carbon emissions, and he practises what he preaches - he won’t be flying to COP this year so as to minimise his own carbon footprint.

Presented by Jim Al-Khalili Produced by Beth Eastwood Executive Producer: Alexandra Feachem A BBC Studios Production