Position the carbon ledger as a governed sub-ledger adjacent to finance and operations systems, with bi-directional integration to ERP (for vendors, cost centers, invoices) and OT/IoT sources (meters, fuel systems). Use the data lake for raw telemetry and unstructured supplier files, while the ledger stores curated, versioned activity data, emission factors, and calculation outputs as the system of record. Publish aggregated facts to the data warehouse for BI, scenario analysis, and disclosures. This separation preserves lineage: raw in lake, gold-standard in ledger, analytics in warehouse.
Key integration points include identity/master data (org hierarchy, facilities, assets), reference data (GWPs, emission factors), and period-close signals from finance. Implement controls analogous to financial ledgers: posting rules, approval workflows, and audit trails linking every posted emission to source evidence and factors.
Architecturally, align with recognized disclosure frameworks (GHG Protocol) to ensure fields support scopes, boundaries, and recalculation policies, and map to ISSB/ESRS reporting structures. Enterprise solutions (e.g., Microsoft Cloud for Sustainability) illustrate reference architectures combining data ingestion, calculation, and reporting layers.
Citations: GHG Protocol Corporate Standard (inventory quality, boundaries); ISSB S2 (disclosure-ready data); Microsoft sustainability architecture.
Key Takeaway: Ledger = curated system of record; lake = raw inputs; warehouse = analytics, with strong controls and finance-grade integrations.