The term “Tipping Point” is commonly used and the concept understood. In Systems Theory terms, a tipping point is reached when the dominant Attractor in a system is changed or the system Type itself is changed.
The Tipping Point is usually reached after a long period of low-level subversive action that is often not noticed. The mechanism of such action is described under Progressive Displacement and the Ratchet Effect.
Once a Tipping Point is reached transformation of the system is usually alarmingly rapid. In the case of eutrophication, a water body “suddenly” within a year or two is infested with algae and weeds. The fact of the matter is that the eutrophication process has been progressing below the surface for many years, and only once the Tipping Point is reached does this fact become apparent in the algae blooms.