The Thermodynamic Discounting Theorem: An Endogenous Discount Rate Reconciling the Stern and Nordhaus Poles

Staged thematic record of the Viridis Canon (route: S1 (Valuation)). The Intelligence-Bound spine is unchanged (frozen at v10.0.0, record 20801185); this record links to it via isDerivedFrom the concept DOI 10.5281/zenodo.19317982. Derives the discount rate for valuing future restoration from physics rather than choice. A single critical horizon τ*=√(A/B) separates two regimes: abundant time (past τ*) gives an endogenous discount rate of exactly zero (the Stern pole); scarce time (before τ*) gives a strictly positive rate rising to +∞ at tipping (the Nordhaus pole). One law, two regimes, one crossover. Collapses to the undiscounted Thermodynamic Valuation Theorem at zero shadow price. CONVERGENCE EVENT; 22nd IB self-application (the Appraiser). The 6 core theorems are machine-checked in Lean 4 (Aristotle, zero sorry, axioms ⊆ {propext, Classical.choice, Quot.sound}, statements verbatim and non-vacuous). Scope: the Lean proofs certify the validity of the discrete reasoning, not empirical magnitudes. Working record; paper pending; not peer-reviewed.