UK Net Zero policy design and deep uncertainty - The need for an alternative approach

The majority of global emissions scenarios compatible with holding global warming to less than 2 degrees C depend on the large-scale use of Greenhouse Gas Removal (GGR) technologies. Recent critiques have highlighted the concerns of building long-term climate policy on such speculative technological scenarios emerging from orthodox modelling approaches - including integrated assessment modelling prominently assessed by the IPCC. Through a stakeholder consultation process with the UK modelling and policy community, we critically examine the integration of GGR technologies into UK Net Zero scenarios and the decision-making philosophy underlying the use of orthodox modelling to inform UK climate policy. We identify a number of features of orthodox modelling approaches which are unable to manage the pervasive extent of deep uncertainty in possible UK climate and energy futures. We further argue that a more fundamental issue lies in the way that the models are used by UK climate policy makers: that the handling of uncertainties which pervade the integration of GGR into Net Zero policy are resulting in substantial distortions in net-zero policy design and associated decision-making. Drawing on the principles of decision-making under deep uncertainty techniques, exemplified by Robust Decision Making, we recommend an alternative approach that explicitly embraces uncertainty, multiple values and diversity among stakeholders and viewpoints, and in which modelling exists in an iterative exchange with policy development rather than separate from it. We advocate that such an approach would provide more relevant and robust information to near-term policymaking and enable an inclusive societal dialogue about the appropriate role of GGR within UK climate policy.