The representation of biodiversity in integrated assessment models: state of the art and directions for improvement

Abstract The biodiversity loss and climate change crises are deeply interlinked. Improving the representation of biodiversity in integrated assessment models (IAMs) is key to bridging climate change mitigation and biodiversity conservation policy. Reviewing 38 studies (2006–2025) that have incorporated biodiversity into IAMs, we identify two different paradigms. On one hand, the use of biodiversity indicators dominates the literature, using spatially explicit models that post-process IAM results and focus on habitat loss and climate change impacts globally. These studies assess how different socio-economic scenarios impact biodiversity. On the other hand, scarcer literature examines how climate-driven biodiversity loss affects human well-being. These studies use damage functions to endogenize how ecosystem service degradation affects the economy on a global scale. From this analysis, we propose that these two approaches should reconcile, by better representing biodiversity-to-economy feedbacks, or by using spatial data and biodiversity indicators. Overall, all IAMs should also improve the representation of freshwater and marine ecosystems. We provide methodological approaches for bidirectional ecosystem-economy integration. Enhancing biodiversity representation in IAMs will enable more comprehensive policy scenarios for both biodiversity conservation and climate change mitigation, while providing a more realistic representation on limits and co-benefits for climate policy.