The high-tech race to improve weather forecasting

Matteo Dell’Acqua has to shout to make himself heard. Engine Room Number Five at the European Centre for Medium-Range Weather Forecasts’ data centre in Bologna houses a series of motors, each turning a three-tonne flywheel. Should the electricity cut out, the flywheels—and those in four other rooms elsewhere in the building—have enough momentum to keep the ECMWF’s newest supercomputer running until the back-up diesel generators fire up.