Nexus and synergy between the low-carbon economy and circular economy: A systematic and critical review

The circular economy and low-carbon economy are closely interconnected as pillars of global sustainable development. However, no consensus exists on how to maximize the carbon reduction benefits of circular practices. This paper illustrates the nexus and identifies synergy paths between low-carbon actions and circular practices via a systematic and critical review. Results show that the mutual promotion relationship is the most studied in the existing literature (63.48%), followed by the parallel status (38.20%) and the trade-offs (3.37%). To enhance synergy mechanisms such as urban-industrial symbiosis and critical raw material cycles, challenges related to cost/risk reduction, urban/industrial planning and inter-system barriers should be addressed. Potential trade-offs arise mainly from carbon-intensive electricity, circular economy rebound and raw material scarcity, requiring a comprehensive consideration of the territorial energy supply structure and circular economy chains. Fiscal and informational interventions from the government, and the technological and business innovations they foster, are the shared drivers. Low-carbon actions and circular practices work together to serve the sustainable development of entities under various scales and dimensions. Three principles are proposed for decision-makers to maximize synergies and minimize trade-offs: (1) prioritize non-end-of-life strategies to meet the surging demand for critical raw materials in the short term, (2) adjust the mix of circular practices following the pace of low-carbon energy transition, and (3) implement more bio-projects that contribute to a win-win situation for the transition to renewable energy and integrated bio-waste management. Briefly, circular practices reduce carbon emissions more effectively when tailored to local and immediate conditions. Future research should focus more on the time-varying features of different circular practices, factors behind household and individual behaviors, and social sustainability.