The first discussion in the Oxford Net Zero Series, hosted by the Oxford Martin School, hones in on the fundamental motivation of the research programme: ‘Why net zero? Join the Oxford Net Zero Initiative’s Research Director, Professor Sam Fankhauser; Director, Professor Myles Allen; Net Zero Policy Engagement Fellow, Kaya Axelsson as they discuss with the Chair, Executive Director. Dr Steve Smith, the meaning of the word ‘net’ in net zero, reviewing what is needed to mitigate global warming, as and before we fully phase out activities that generate greenhouse gas emissions. The discussion will explore the framing opportunities and challenges that the term ‘net-zero’ offers for science, policy, and advocacy informing effective climate action, as well as the innovation required at scale to achieve the global goal.