We present the first digital twin framework that operationalizes the production of multi-decadal, global climate projections at kilometre-scale resolution, developed within the European Union’s Destination Earth initiative. Using three coupled Earth system models and selected impact-sector applications, we have built end-to-end workflows for both regular and on-demand climate projections on two EuroHPC supercomputers, LUMI and MareNostrum5. These workflows produced the first-ever multi-decadal simulations at 5 km resolution across all major Earth system components, using the same output parameters and grid, and achieving a production throughput of 0.6 simulated years per day and a climate data portfolio of 6.6 petabytes. We demonstrate the scalability of two of these Earth system models across both CPU and GPU-based systems at global resolutions up to 1 km, across atmosphere, ocean, land, and sea-ice, and report record-breaking full-machine performance on LUMI and MareNostrum5 of up to 97 simulated days per day at 1 km resolution.

Climate models are steadily evolving towards higher resolution and the upcoming model inter-comparison projects require an unprecedented number of produced variables. As a consequence, the post-processing of the output of these models start to form a bottleneck for CMIP experiments. We discuss how the ece2cmor3 tool processes the EC-Earth model output in parallel, and present a new coupling of the ECMWF weather model to the XIOS library to allow on-the-fly post-processing of its atmospheric fields.