Climate Pathway Design: High-Risk Futures and Distributional Implications: Dr. Mel George

Integrated assessment models are used to construct global reference scenarios and evaluate the consequences of alternative mitigation pathways. This presentation draws on recent research in both areas, focusing on the development of a new high-emissions marker for CMIP7 and the regional and household distributional consequences of mitigation strategies.

The presentation begins with H3, the marker for CMIP7’s high-emissions scenario, whose development I led. H3 takes over the high-end reference role associated with RCP8.5 for more than a decade in climate and impacts research. It reaches approximately 6.5 W/m² of radiative forcing and 3.4°C of warming by the end of the century, below the corresponding CMIP6 marker and SSP5-8.5. H3 represents a high-risk future shaped by substantial warming, fragmented development, persistent vulnerability, and limited adaptive capacity. It provides a high-end reference scenario in which climate hazards interact with socioeconomic conditions to determine risk.

The second part examines how mitigation pathway design shapes distributional outcomes across regions and households. Cost-optimal and technology-led strategies exacerbate tensions among energy equity, sustainability, and security, with developing regions experiencing greater equity losses. Pathways that reduce energy demand among affluent populations alleviate these tensions across developed and developing regions. The household consequences are particularly pronounced in India. Under cost-optimal pathways, rising modern-fuel prices increase reliance on traditional biomass among the poorest income groups, reversing part of the clean-cooking transition that mitigation is intended to support. Demand-side pathways reduce energy burdens and produce a more progressive distribution of mitigation outcomes across households.

For India and the wider Global South, these findings point to two priorities. High-end climate assessments must account for the socioeconomic conditions that shape vulnerability and adaptive capacity. Evaluations of mitigation pathways must consider emissions reductions alongside consequences for energy access, household welfare, and existing development inequalities.