6. AMOC

The Atlantic Meridional Overturning Circulation — AMOC — is one of the planet's most consequential fluid systems: a vast conveyor of heat that keeps Northern Europe habitable, has switched abruptly between "on" and "off" states at least 25 times in the last 115,000 years, and may currently be weakening. This document applies the SFVFS™ framework to that system and finds a precise geometric match — the entire overturning flux of the Atlantic passes through less than 5% of the ocean's surface area, in the convective chimneys of the Labrador and Nordic Seas where warm, salty water cools, densifies, and sinks, and that narrow passage is the Needle's Eye: the VOID state of the SFVFS™ cycle, inhabiting the open interval between collapse and runaway. The framework introduces a measurable diagnostic, Γ_THC — the ratio of buoyancy drive to combined mixing and diffusion resistance — predicting it sits below 1 during stable AMOC and rises toward 1 as the system approaches tipping, with the current weakening trend representing a measurable Γ_THC rise testable against ARGO float and RAPID array data. The saltwater canonical DNS result (Cell A, θ_s = 50.103°) provides direct empirical grounding, anchoring AMOC's geometric attractor in the Shallow Void family and elevating the prediction from theoretical extrapolation to falsifiable conjecture. The framework does not predict whether AMOC will collapse. It names exactly what collapse would look like, and where to look for it first.