How precisely can supercomputers forecast heavy rainfall, Mr Stevens?

In 2022 at his institute in Hamburg, for instance, “Levante” went into operation. The supercomputer can handle 14 quadrillion operations per second. “It will enable us to do long-term simulations with climate models with a grid resolution of three kilometres, for example,” says Stevens. The researcher is modifying Levante’s code so that simulations run at their optimum. Up to now, global simulations based on models with such fine grids could only be achieved for up to a few months. Levante, however, will make them calculable for several years.

But if you want to understand how heavy rainfall will change with global warming, for example, you need computers that are hundreds of times more powerful than Levante. Stevens and some of his colleagues are calling on climate computing centres internationally to join forces in order to get access to this new generation of supercomputers. In 2024, a machine of this kind is scheduled to go into operation at Forschungszentrum Jülich.