Governance Layer
Review workflow, approval chain, model change log, and audit log.
Review Workflow
Internal Model Calibration
Owner: Quantitative Methods Team
Deliverable: Updated parameter file with change notes
Scientific Peer Review
Owner: Climate Science Team
Deliverable: Review memo confirming scientific validity
Assumption Audit
Owner: Risk & Governance Team
Deliverable: Updated assumptions registry with any new flags
Validation Run
Owner: Quantitative Methods Team
Deliverable: Updated validation records with error rates
Decision-Grade Certification
Owner: Chief Model Officer
Deliverable: Certification memo; version tag applied
Annual full review: Q4 annually · Scope: All EQUATIONS, PARAMETERS, ASSUMPTIONS, SOURCES, MODEL_INVENTORY · External review: Independent scientific advisory panel
Approval Chain
Quantitative Methods Lead
Responsibilities: Parameter calibration; MC convergence testing; Validation runs
Change authority: PARAMETERS, VALIDATION_RECORDS
Escalation: Error rate >20% or critical parameter flagClimate Science Lead
Responsibilities: Climate equation review; Source provenance; AR6/NGFS alignment
Change authority: EQUATIONS (climate category), SOURCES (climate), ASSUMPTIONS (climate)
Escalation: New IPCC/UNEP data release within 90 daysEconomics & Risk Lead
Responsibilities: Economic model calibration; Damage function selection; SCC range
Change authority: EQUATIONS (economics, damage), PARAMETERS (economics), ASSUMPTIONS (economics)
Escalation: Damage function literature diverges >25% from CE calibrationRisk & Governance Officer
Responsibilities: Assumption audit; Flagged parameter review; Governance log maintenance
Change authority: ASSUMPTIONS, GOVERNANCE (this file)
Escalation: Critical assumption challenged in peer review or external auditChief Model Officer
Responsibilities: Decision-grade certification; External review commissioning; Board reporting
Change authority: ALL (final sign-off)
Escalation: Any failed validation test or material model changeModel Change Log
| ID | Date | Type | Registry | Affected | Summary | Approved by | Stage |
|---|---|---|---|---|---|---|---|
| CL-001 | 2026-02-10 | param update | PARAMETERS | P-CLM-003 | Updated global baseline emissions from 57.0 GtCO₂e (UNEP EGR 2023) to 57.4 GtCO₂e (UNEP EGR 2024). | Climate Science Lead | 4/5 |
| CL-002 | 2026-02-01 | calibration | PARAMETERS | P-UNC-002 | De-duplication factor δ revised from 0.20 to 0.22 following review of IEA NZE 2023 accounting methodology. | Quantitative Methods Lead | 4/5 |
| CL-003 | 2026-01-20 | validation | VALIDATION_RECORDS | VAL-DAM-001 | Added historical validation of DamageModelService AAL against Swiss Re sigma 2000–2022. | Risk & Governance Officer | 5/5 |
| CL-004 | 2026-01-15 | source | SOURCES | SRC-UNEP-001 | Upgraded UNEP EGR source from 2023 to 2024 edition. | Climate Science Lead | 3/5 |
| CL-005 | 2026-02-05 | assumption flag | ASSUMPTIONS | A-TECH-001 | Breakthrough technology scale-up assumption flagged as 'historically_not_validated'. Risk note added. | Chief Model Officer | 5/5 |
Audit Log
Full Registry Review — All 6 registry files reviewed for completeness and consistency
3 parameters flagged for enhanced monitoring (P-DAM-001, P-ECO-002, P-UNC-002). All validation tests passed.
Performed by: Risk & Governance Officer
Monte Carlo Convergence Test — MonteCarloEngine N=2000 convergence validation
P5/P95 stable within ±1.3% at N=2000. No parameter distribution anomalies detected.
Performed by: Quantitative Methods Team
External Advisory Review — Climate equations and damage function selection
Panel endorsed TCR-based warming approach. Recommended adding Burke et al. (2015) as explicit alternative assumption to DICE damage function. BECCS ceiling documented. Breakthrough technology assumption flagged.
Performed by: External Scientific Advisory Panel