Towards standardised metrics of performance, energy and carbon footprint for CMIP experiments

Global climate models are among the most computationally demanding scientific applications, with rapidly increasing resolution and complexity driving unprecedented requirements in high-performance computing. While model intercomparison efforts have traditionally focused on scientific output and physical fidelity, the computational performance, energy consumption and carbon footprint of climate simulations are becoming critical factors for the sustainability of next-generation modelling activities.

Building on previous coordinated work done for CMIP6, this work extends the scope towards a global assessment framework applicable to all major climate models. We present a list of metrics applicable to climate simulations to systematically quantify model performance, energy cost and associated carbon footprint using standardised and reproducible metrics across supercomputing platforms. The proposed framework combines workload analysis, runtime monitoring and workflow-level instrumentation to enable consistent comparisons between modelling systems.

This effort is conducted in the context of the World Climate Research Programme ESMO Infrastructure Panel (WIP), where a dedicated task team is coordinating the systematic collection of performance, energy and carbon footprint metrics from modelling centres participating in CMIP7, in collaboration with initiatives such as ESiWACE, ENES-RISe,  Destination Earth and FUTURA. The objective is to establish community-endorsed metrics and monitoring practices that can be integrated into operational model development and production workflows, from CMIP7 and beyond.

By treating computational efficiency and carbon footprint as first-class metrics in climate model evaluation, this work aims to support informed decisions on model design, resource allocation and optimisation strategies, contributing to a more efficient and sustainable future for global climate modelling.