World leaders have offered up a suite of promises at the COP26 climate summit in Glasgow but how many of them will make a real dent in our greenhouse gas emissions? Tom Heap talks to experts in sustainable finance, methane emissions, deforestation, clean technology and energy to gauge the impact made so far. He's also joined by two veterans of many COP meetings, University of East Anglia climate scientist, Corinne Le Quéré and Bernice Lee of Chatham House. What do they make of the conference that the world is watching? Producer: Alasdair Cross