European power grids are losing inertia fast. As gas and nuclear generators clear in the market less often, the spinning mass that once stabilised the grid frequency is reducing. Inverter-based resources (wind, solar, and grid-following BESS) currently provide no inertia at all. The result is a grid that responds more violently to disturbances, where smaller events trigger larger frequency swings. The worst-case scenario - a continental system split leading to widespread blackouts - becomes harder to plan for.