IAM_COMPACT_D3.5_Model_interlinkages_and_integration_Update

Over the years, energy-system models (ESMs) and integrated assessment models (IAMs) have become indispensable for evaluating our progress toward climate targets, crafting pathways that align with specific goals, and judging the impact of various mitigation strategies. As the urgency of the climate crisis has grown, so too has the need to encompass a broader range of sectors and the interactions between them. However, expanding a model’s boundaries often adds layers of complexity. To address this without overwhelming individual models, researchers frequently link established models together, allowing cross-system dynamics to emerge organically through those connections. Connecting models not only broadens the analytical scope but also deepens detail in particular sectors while preserving the overall systemic context. Despite its widespread use, model linking presents numerous challenges—arising from differing assumptions, structures, data formats, and temporal or spatial scales—that are seldom explored in depth within published studies. In this deliverable, we first discuss four key problems that are central to most model linking activities, then develop a general “checklist” to be used when considering model linking. We finally demonstrate the use of the checklist for a study carried out in the IAM COMPACT project.