(Path)ways to sustainable living: The impact of the SLIM scenarios on long-term emissions

Sustainable lifestyles and behaviour changes can be vital in climate change mitigation. Various disciplines analyse the potential for such changes – but without much interaction. Qualitative studies look into the change process (e.g. social practice theory), while quantitative studies often focus on their impact in stylised cases (e.g. energy modelling). A more holistic approach can provide insightful scenarios with diverse lifestyle changes based on informed narratives for quantifying long-term impacts. This research explores how comprehensive sustainable lifestyle scenarios, coined SLIM (Sustainable Living in Models) scenarios, could contribute to transport and residential emission reductions. By translating and quantifying lifestyle scenario narratives through engagements with advisors and policymakers, we modelled two distinct lifestyle scenarios which differ in their degree of access to structural support. In one scenario, governments, corporations and cities leverage existing values and market systems to shape citizen and consumer preferences and everyday practices. In the other scenario, people adopt ambitious sustainable lifestyle behaviours and practices through peer-to-peer interaction and digital technology. We quantified the scenarios based on motivations, contextual factors, extent, and speed of lifestyle adoptions with regional differentiation. Furthermore, we applied heterogenous adopter groups to determine the model inputs. We present the resulting pathways in per capita emissions and more detailed changes in total emissions via decomposition analyses. We conclude that regional differentiation of the scenario narratives and modelling of intra-regional differences allows accounting for equity in lifestyle changes to a certain extent. Furthermore, new technologies are more important for enabling lifestyle change in a scenario with than a scenario without strong structural support. With strong structural support, lifestyle changes reduce transport and residential emissions to a larger degree (about 39% for Global North and 27% for Global South overall in 2050 relative to a “Middle-of-the-Road” SSP2 reference scenario in 2050). Thus, lifestyle changes in larger systems change are essential for effective climate change mitigation.