The (Co)Benefits Portal—an evidence-based and climate policy-relevant tool for decision-making

From improving health outcomes and health inequalities to ensuring energy and income security, the mitigation of and adaptation to climate change has extensive and diverse benefits. This paper describes a systematic evidence synthesis of climate action (co)benefits and trade-offs as well as the development of a decision-support tool that enables policy makers to explore that evidence-base. The term ‘(co)benefit’ is used deliberately to encompass both the direct benefits of averted impacts due to climate change as well as the indirect or ancillary benefits resulting from mitigation and adaptation interventions. We conducted a systematic search of the peer-reviewed literature in the IPCC 6th Assessment Report, Web of Science, and the Lancet Countdown on Health and Climate Change Reports. Our search strategy prioritised synthesised evidence (e.g. reviews, assessments) excluding primary studies and single case-studies. Data were extracted from 74 distinct records meeting our inclusion criteria and a total of 1785 rows of evidence were analysed. Scientific and technical teams then worked together to develop a tool interface that underwent iterative testing among a small group of potential users. The resulting (Co)Benefits Portal presents an assessment of the available scientific evidence of health, ecosystem, economic, energy, and socio-cultural (co)benefits and trade-offs associated with 40 different mitigation and adaptation actions for both global and regional scales. We then apply the (Co)Benefits Portal into a UK context, in combination with national policy documents and departmental guidance, to connect evidence about relevant climate interventions and reveal cross-sectoral policy implications that are essential for optimising opportunities and avoiding risks. We discuss how evidence-based tools can be developed to bridge critical climate adaptation and mitigation research, policy, and decision-making gaps.