Cairn

Cairn turns public climate data into auditable, reproducible datasets with full lineage.

We build reproducible climate datasets from official public sources with complete lineage — CSRD/ESRS reporting is one application.

For sustainability teams, auditors, and software vendors who need to prove every number back to an official source.

The two benchmarks

Cairn pairs two official sources that answer the question at two altitudes — the whole-economy denominator and the installation-level numerator.

Why it is auditable

Cairn is built on a few load-bearing rules, so a number can never drift away from its source:

• Raw data is immutable — every ingest writes a new, versioned path.
• The manifest is append-only — each source pins its exact release by sha256; a data change without a manifest change is impossible.
• Mappings are code — the CBS category → NACE mapping is a reviewed seed, so its numeric impact shows up in a CI diff.
• CI guards the methodology — reconciliation and coverage tests fail the build if a source shifts under us.

See Methodology & sources → for the full provenance of every figure on this site, or Data quality → for the live pin status of each source — whether every figure is still chained, by hash, to an immutable official source. The Data dictionary & glossary → lists every model and column with the tests that guard it, and defines the cross-cutting concepts behind the numbers.

The CSRD / ESRS E1 disclosure → supports ESRS E1-6 reporting by providing an auditable source for the verified Scope 1 emissions of EU ETS installations — downloadable as a self-contained, audit-traceable bundle.