Cosmic star formation peaked at z of 2 and has fallen tenfold since, while gas kept accreting, molecular reservoirs stayed substantial, and halos kept growing. ΛCDM must therefore lower star formation efficiency everywhere at once by an order of magnitude, using feedback mechanisms that track local conditions, not cosmic epoch. The most prominent feature of star formation history is fit by construction, never predicted, and its global synchronization is unexplained.
The model has no global clock: with a constant Λ and locally governed baryonic physics, nothing epoch-wide can change at z of 2, so a synchronized downturn must be assembled from local feedback patches that happen to fire together everywhere. The cliff's timing has nowhere to come from.
SCT supplies exactly the global clock the cliff requires. The dynamical ratio Λ_eff(x,t) = C × Λ_parent / λ_local grows through the structure era as mesh dissipation proceeds (P14, P15, P16, P17): rising Λ_eff progressively suppresses the accretion of fresh gas from the cosmic web onto bound systems, throttling the fuel line everywhere on the same schedule because the mesh evolves everywhere on the same schedule. The downturn at z of 2 marks the epoch when mesh-driven expansion enhancement began outcompeting infall at galactic boundaries, a synchronized, epoch-tagged transition no local feedback patchwork can supply (P18).
One prologue layers underneath: star formation initially ran on the seeded reservoirs that collision deposition placed in proto-structures (P22, P25, P29), and the rise to cosmic noon tracks the burn-through of that endowment. The cliff is therefore two-sided by construction: a seeded fuel supply maturing into exhaustion just as the mesh clock throttles replacement. Feedback remains real physics regulating individual systems, but the epoch and the universality belong to the Λ_eff schedule.
This is the same mesh evolution that drives the Hubble tension, the DESI w(z) artifact, and the S₈ family, here read in the star formation ledger. There is no need to invoke a feedback conspiracy synchronized across all environments.
The clock signature is environmental: SCT requires the downturn's onset to correlate with local Λ_eff conditions, arriving earliest where mesh enhancement is strongest (void-adjacent systems) and latest in the most deeply bound environments. Joint gas-and-star-formation surveys through cosmic noon finding the decline strictly local-condition-driven, with no environmental phasing and full explanation by feedback energetics, would remove the global clock. The Hubble-tension kills inherit: no void-versus-cluster H(z) difference at the 2 percent level guts the same mechanism.