A second pathway occurs when resilience has weakened enough that a shock or fluctuation can push a system into another state. In this case, tipping is not explained only by the average level of forcing; the size of disturbances and the system's remaining stability also matter.
Repeated stress can reduce redundancy, spare capacity, maintenance reserves, ecological buffering, or the ability of institutions and communities to recover. The system may still appear functional, but the basin of conditions from which it can return to its previous state has narrowed.
Once resilience is low, an extreme event or even an ordinary fluctuation can have a disproportionate effect. In an urban context this could mean a heatwave coinciding with a power outage, a storm affecting already degraded drainage, or a health service facing an additional demand spike when capacity is already stretched.
The preventive logic is to build resilience and reduce vulnerability to shocks. Useful measures include redundancy, maintenance, backup power, spare service capacity, diversified supply routes, social protection, accessible emergency support, and targeted investment in populations and places with the least capacity to absorb disruption.
