Taylor's Law as Empirical Operationalization of the GCT Dimensional Limit: 600 Estimates Confirm b → 2 as d → ∞ with Solar Modulation Across Five Solar Cycles

Tests the GCT prediction that Taylor's Law exponent b → 2 as d → ∞, derived from the coupling equation α(d,β) = (2d+β)/(d+β). 600 b estimates drawn from independent analytical units across five ecological datasets (USGS BBS, BioTIME, GBIF, 31 extinct species, rhinoceros populations) yield empirical median b = 1.944, within 0.005 of the d=4 ecosystem attractor (95/49 = 1.9388). The residual Δ = 0.005 is interpreted as consistent with the IE-006 feedback delta (HLRP #152, 10.5281/zenodo.19641592). Extinct species show b ≈ 3.0 (6 SE above living distribution), consistent with a three-regime framework and IE-002 ceiling breach. Declining bird populations show b increasing over time (r = −0.153, p = 0.0014, n=433 species). Secondary finding: community-level Taylor b from 49 five-year BBS rolling windows (1968–2017) shows lagged negative correlation with solar activity (SILSO SSN, lag +4yr, r = −0.407, p = 0.0055; phase-scramble null p = 0.042), with Lomb-Scargle dominant period of 11.7 years across five solar cycles. The d=4 attractor was on record in HLRP #147 and #143 prior to this analysis. The prediction preceded the measurement.