There’s an easy way to cut carbon emissions from digital advertising. Stop buying “crap” ads that “no human sees”, ditch “gamed” viewability metrics and instead buy on attention, never buy another outstream video ad, and cull the bloated programmatic supply chain, per Brian O’Kelley. The CEO of Scope 3, a global emissions measurement firm focusing on decarbonising digital media and advertising, knows how much waste lurks within that supply chain – the sprawling Lumascape – because he was in deep and early, founding AppNexus, which ultimately sold to ATT&T for $1.7bn. Even “turning off five to seven per cent of inventory gets you a 29 or 30 per cent reduction in carbon,” says O’Kelley. Publishers feeling the heat to decarbonise – GroupM and Mediabrands are talking about money moving next year – needn’t fear. He reckons they will see more cents in the ad dollar as the bad actors get punted. Marketers will also stop wasting billions of ad dollars while saving millions of tonnes of carbon. But marketers have to lead, because everyone else will follow the money. Suncorp CMO Mim Haysom, NAB Head of Marketing Planning & Performance, Tom Dobson, and Australian Marketing Institute CEO, Bronwyn Powell join Mi3 on the mics to ask the pointy questions on where next – and how fast.