
A feeder model that learned from Living Worlds' checked simulation first, then from a handful of real measurements, predicted 30 unmeasured low-voltage feeders better than the same model on real measurements alone; power through 40 unmetered feeders beat physics and a learned model; thermal comfort in fifteen countries came close but was not met.

Learned weather models are now operational, faster and often more skilful than physics on ordinary days, and weaker on record-breaking ones. The habits that made them trustworthy, daily scoring against what happened and honesty about extremes, are what simulation of lives and economies needs next.

Europe's grid operators, its cities and its climate programme all moved digital twins from plans to infrastructure in 2025-26. The architecture is now well specified; the step that decides whether a twin can be relied on is a prediction scored against what it never measured.