The climate community has set ambitious goals to reach global km-scale modeling capability on future exascale high-performance computing (HPC) systems. But currently, state-of-the-art CMIP simulations are executed using grid spacing’s of 25 – 50 km and none of the productive climate models is capable of exploiting modern HPC architecture with hybrid node designs. In this talk we present near-global simulations using a regional climate model (COSMO) that have been executed on Europe’s largest supercomputer, Piz Daint. COSMO has been systematically adapted for performance portability on multiple hardware architectures and is capable of scaling onto the full system size for large enough problem sizes. The results presented can serve as a baseline of what could be achieved today using a state-of-the-art atmospheric model on a modern, accelerated hardware architecture. Finally, we conclude by highlighting some of the remaining challenges and potential solutions on the way to global km-scale climate simulations.
