Advancing representations of justice and the social sciences in climate mitigation futures

As the Intergovernmental Panel on Climate Change (IPCC) enters its seventh assessment cycle (AR7), the scientific community faces a pivotal moment of reflection regarding the role of global modelled scenarios in shaping the international climate policy landscape. The Sixth Assessment Report (AR6) highlighted pathways toward the Paris Agreement but also surfaced tensions between cost-optimal global scenarios and heterogeneous levels of national development, mitigation capabilities, and historical responsibilities for climate change. This invited presentation frames the session by interrogating current approaches to justice in climate mitigation research and proposes a research agenda for its transformation.

We first establish a typology of justice-related critiques on the current generation of scenarios. This typology distinguishes between three interrelated dimensions of the modelling process. Structural limitations of the research culture pertain to the geographic and disciplinary concentration of modelling expertise in the Global North, specifically in Europe, North America, and Japan, which has historically privileged certain epistemological contexts while perspectives from Low- and Middle-Income Countries (LMICs) and Small Island Developing States (SIDS) remain underexplored. This lack of diversity shapes narratives constructed and solutions deemed feasible. Next, we discuss methodological biases inherent in model architectures. Standard modelling approaches privilege scenarios that allocate high mitigation burdens to regions with high technical mitigation potential but low institutional and financial capacity, effectively neglecting the principle of common but differentiated responsibilities and respective capabilities. These choices effectively prioritise technoeconomic efficiency over intergenerational and interregional equity. Finally, we discuss epistemological boundaries limiting the breadth of indicators relevant to informing national policy, and the limited contextualisation of scenario outputs within heterogenous policy regimes that face differentiated costs of capital and risks.

Responding to these challenges, we propose a tiered research agenda designed to integrate considerations of justice into scenario design and use. Tier one advocates for incremental refinements within existing frameworks. This includes improving the transparency of model inputs, downscaling global results to policy-relevant national scales and for relevant indicators, and systematically integrating climate impacts and loss-and-damage considerations. Tier two calls for more fundamental advancements in scenario frameworks, including emerging work that replaces blind economic growth narratives with convergent pathways centred on Decent Living Standards (DLS) and multidimensional well-being. This involves reconceptualization of the solution space to prioritize demand-side transformations, sufficiency-based lifestyles, and protection of ecological thresholds that support both human and non-human life. We also emphasize the need for scenarios that explicitly model effort-sharing principles from the outset, incorporating differentiated carbon budgets and international climate finance flows as internal model objectives rather than ex-post calculations. Tier three focuses on procedural justice through participatory co-production. We argue that the legitimacy of future scenarios depends on the sustained engagement of a broader set of stakeholders, including social scientists, humanities scholars, and frontline communities, in the design and interpretation of narratives. This shift requires institutional reforms to support modelling capacity in the Global South and to move beyond tokenistic consultation toward genuine co-production of knowledge.

While models cannot fully capture equity and justice, strengthening them is essential to inform just collective action.