Implementing global climate damage functions in a new Integrated Assessment Model

The coupled interactions between components of the human-Earth system – impacts of human activity on the climate, and vice versa via climate impacts – are thought to be crucial determinants of the evolution of this system. However, the representation of these feedback loops is often minimal, or intentionally excluded, in existing integrated assessment modelling approaches.

The new global Integrated Assessment Model FRIDA v2.0 seeks to represent climate impacts as comprehensively as possible, at the global scale, focusing on high-level feedbacks between components of this system. This broad scope and high level of aggregation necessitates a reduced focus on individual impact channel complexity, with impacts simulated as functions of key global climate variables – e.g. temperature, CO2 concentration, and sea level rise.

Through this process, we have implemented key impact channels in FRIDA – on e.g. crops, energy supply and demand, mortality, and human behaviour. These channels generate substantial, complex effects on the evolution of the fully coupled human-Earth system.

In this presentation, we detail the process of collating and modelling climate impact channels within FRIDA v2.0, and present initial results of their overall effects on the system. We discuss the challenges of extracting internally consistent estimates from the literature, dealing with uncertainty across and between studies, conceptualising extremes. Finally, we discuss the need for future work to construct more comprehensive, consistent damage functions, and to coordinate their implementation in IAMs.