The Circular Scope 3 (CS3) tool: Quantifying greenhouse gas reductions from circular economy strategies for science-based target reporting

As companies are increasingly committed to the Science Based Targets initiative (SBTi), the Circular Economy (CE) has been identified as a prominent approach for reducing greenhouse gas (GHG) emissions. However, there is currently no standardised methodology for companies to quantify the GHG reductions from specific CE strategies. This is particularly challenging for Scope 3 emissions, which often constitute the largest portion of a manufacturing company's carbon footprint, hindering effective decarbonisation efforts and investment in circular models. To address this challenge, this research presents a significant innovation: the development and validation of the Circular Scope 3 (CS3) Tool. The CS3 is a novel, operational instrument specifically designed for non-energy intensive manufacturing companies to measure and report Scope 3 emissions from CE strategies in direct alignment with SBTi requirements. The tool's design was informed by a systematic literature review consisting of 70 articles and an evaluation of 38 existing tools. After its development, the tool was tested using a washing machine case study and refined via several workshops conducted with industry experts and corporate partners. The primary contribution of this work is the provision of a replicable and robust framework that bridges the gap between CE theory and corporate climate action, enabling companies to make evidence-based decisions and prioritise circular strategies that can contribute to achieving their science-based Scope 3 targets. • A standard method is needed to link CE actions to verifiable GHG reductions. • The CS3 operational tool quantifies Scope 3 emissions of circular economy strategies. • CS3 enables evidence-based prioritisation of circular economy strategies. • Practitioners can use the tool to track and align corporate SBTi Scope 3 targets. • The tool is validated via a case study and refined through workshops with experts.