Sustainability Ontology

A governed, machine-readable ontology for environmental and ESG data: 128 formally defined O-DEF terms across 3 axes, exposed through a semantic layer API for cross-system alignment and backed by a versioned registry with drift detection.

Three Semantic Axes

Every concept in the ontology is classified along three axes, so each term carries an unambiguous, machine-readable meaning.

Object Classes

What the data element represents (e.g., Resource, Process, Indicator, Ledger)

60
total
13 core
47 sustainability

Roles

The relationship or function of the data element (e.g., Emitter, Trader, Auditor)

28
total
10 core
18 sustainability

Properties

The measurable attribute (e.g., Measure, Amount, Factor, Rating, Identifier)

52
total
14 core
38 sustainability

Governed O-DEF Registry

The ontology is maintained as a versioned O-DEF registry. Changes are proposed, validated, and approved through a governed workflow so the definitions in git stay aligned with the models actually running in production.

Versioned approvals

Every release is a numbered version. Proposed changes become a draft, then a pull request that moves the approved pointer — the audit record lives in git.

Drift detection

The registry is continuously compared against the fields applied in the Open Footprint models. Renames and mismatches are flagged before they silently break consumers.

Validation gates

Registry submissions run the same server-side validation as CI. Breaking changes, numbering gaps, and source corrections are surfaced before approval.

Semantic Codes

Each ontology term carries a 3-axis semantic code. Codes are assigned using O-DEF™ (Open Data Element Framework), The Open Group standard we used to define the semantics.

ObjectClass~Role_Property

Example:

ofp-sustainability:3.101~1.101_5.101

Resource.Emission-Source ~ Trader.Emitter _ Measure.Greenhouse-Gas-Emission

Registry Coverage

60
Object Classes
28
Roles
52
Properties

Ontology Browser

Search and filter across 140 approved O-DEF registry terms.

Person

Object Classesobject class

A human being, whether man, woman, or child.

Semantic code1

Enterprise

Object Classesobject class

A collection of people organized to achieve a common set of goals.

Semantic code2

Enterprise.Reporting-Organization

Object Classesobject class

An enterprise that prepares and submits sustainability / GHG reports under a defined reporting boundary (organizational or operational).

Semantic code2.101

Enterprise.Supply-Chain-Partner

Object Classesobject class

An enterprise within the supply chain that contributes emission data for Scope 3 upstream or downstream categories.

Semantic code2.102

Enterprise.Organization-Association

Object Classesobject class

An association, membership, or relationship between organizations or between an organization and a person.

Semantic code2.103

Resource

Object Classesobject class

A source or supply from which benefit is produced. Typically, resources are materials, energy, services, knowledge, or other assets.

Semantic code3

Resource.Emission-Source

Object Classesobject class

A resource (fuel, feedstock, refrigerant, etc.) that directly or indirectly produces greenhouse gas emissions when consumed or processed.

Semantic code3.101

Resource.Emission-Sink

Object Classesobject class

A resource that removes greenhouse gases from the atmosphere (forests, soil, CCUS storage).

Semantic code3.102

Resource.Natural-Asset

Object Classesobject class

A natural resource subject to ESG reporting: water, minerals, biological assets.

Semantic code3.103

Resource.E-Ledger

Object Classesobject class

A ledger resource for tracking accountability balances, entries, debits, credits, and transfers.

Semantic code3.104

Resource.Equipment

Object Classesobject class

A physical asset - machinery, vehicle, meter, or installed unit - that consumes resources or produces emissions when operated.

Semantic code3.105

Location

Object Classesobject class

A place or position. Typically, locations provide geographic or geometric context that characterizes the data element.

Semantic code4

Location.Facility

Object Classesobject class

A physical installation, plant, or site where emission-producing activities occur.

Semantic code4.101

Location.Jurisdictional-Area

Object Classesobject class

A geographic area defined by regulatory or political boundaries relevant to compliance obligations.

Semantic code4.102

Location.Spatial-Reference

Object Classesobject class

A coordinate reference system, spatial transformation, or abstract spatial location used for geospatial data.

Semantic code4.103

Location.Address

Object Classesobject class

A postal or civic address identifying where an organization, person, or facility can be reached or is registered.

Semantic code4.104

Location.Geological-Feature

Object Classesobject class

A subsurface geological body or interpreted region that emission-producing or carbon-storing activity is attributed to: basin, field, play, prospect, reservoir, rock volume or interpreted boundary.

Semantic code4.105

Event

Object Classesobject class

An occurrence happening at some point or points in time, with or without the participation of human agents.

Semantic code5

Event.Emission

Object Classesobject class

A recording event capturing one or more emission measurements or calculations for a defined period.

Semantic code5.101

Event.Measurement-Environmental-Data

Object Classesobject class

A discrete sensor reading, sampling, or monitoring event producing raw environmental data (CEMS, meters).

Semantic code5.102

Event.Verification-Emission

Object Classesobject class

An audit, assurance, or verification activity applied to emission data.

Semantic code5.103

Event.Allocation-Emission-Quantities

Object Classesobject class

An event where emission quantities are allocated to facilities, activities, organizations, or products.

Semantic code5.104

Condition

Object Classesobject class

A particular mode of being of a person or thing; existing state; situation with respect to circumstances.

Semantic code6

Condition.Compliance-State

Object Classesobject class

The regulatory compliance status of an entity against a specific framework (CSRD, SEC, ISSB).

Semantic code6.101

Condition.Data-Quality-State

Object Classesobject class

The data quality condition of an emission record, assessed against PACT DQI dimensions.

Semantic code6.102

Condition.Quality-Rule-State

Object Classesobject class

A data quality rule, rule set, or assessment state used to evaluate and enforce data integrity.

Semantic code6.103

Condition.Non-Conformance

Object Classesobject class

A deviation from expected data quality, regulatory compliance, or internal standards requiring corrective action.

Semantic code6.104

Environment

Object Classesobject class

The natural or man-made surroundings of someone or something.

Semantic code7

Environment.Climate-Zone

Object Classesobject class

A climatic region that influences emission patterns and baseline assumptions.

Semantic code7.101

Environment.Ecosystem

Object Classesobject class

An ecological system relevant to biodiversity impact assessment.

Semantic code7.102

Law-Rule

Object Classesobject class

A law (natural or man-made) or policy that governs a process.

Semantic code8

Law-Rule.Regulation-Framework

Object Classesobject class

A regulatory or voluntary reporting framework governing sustainability disclosure (CSRD, SEC Climate, ISSB S2, EU ETS).

Semantic code8.101

Law-Rule.Emission-Standard

Object Classesobject class

A technical standard defining how emissions are measured, calculated, and reported (GHG Protocol, ISO 14064, ISO 14067).

Semantic code8.102

Law-Rule.Product-Category-Rule

Object Classesobject class

A product category rule (PCR) or environmental product declaration (EPD) standard governing product footprint calculation.

Semantic code8.103

Process

Object Classesobject class

A series of actions, changes, or functions bringing about a result.

Semantic code9

Process.Emission-Activity

Object Classesobject class

An activity that produces greenhouse gas emissions: combustion, fugitive release, industrial process, purchased energy.

Semantic code9.101

Process.Emission-Calculation

Object Classesobject class

The application of emission factors, allocation methods, or models to convert activity data into CO2e.

Semantic code9.102

Process.Emissions-Remediation

Object Classesobject class

An activity that reduces, offsets, or removes emissions: renewable energy, carbon capture, efficiency improvement.

Semantic code9.103

Process.Approval-Workflow

Object Classesobject class

A workflow process for reviewing and approving emission data, ledger entries, or reports.

Semantic code9.104

Process.E-Liabilities-Transfer

Object Classesobject class

A process for transferring e-liabilities between ledgers, organizations, or products along the value chain.

Semantic code9.105

Product

Object Classesobject class

The result of a process.

Semantic code10

Product.Carbon-Intensive-Production

Object Classesobject class

A product whose production generates significant embodied carbon (steel, cement, chemicals, aluminium).

Semantic code10.101

Product.Carbon-Footprint

Object Classesobject class

A product bearing a Product Carbon Footprint (PCF) as defined by ISO 14067 / PACT.

Semantic code10.102

Product.Lifecycle-Stage

Object Classesobject class

A stage within a product life cycle (raw material, manufacturing, distribution, use, end-of-life) relevant to PCF calculation.

Semantic code10.103

Substance

Object Classesobject class

A material of a particular kind that bears physical and chemical properties. Substances can be solid, liquid or gaseous.

Semantic code11

Substance.Greenhouse-Gas

Object Classesobject class

A gaseous substance contributing to radiative forcing: CO2, CH4, N2O, HFCs, PFCs, SF6, NF3.

Semantic code11.101

Substance.Pollutant

Object Classesobject class

A non-GHG substance causing environmental pollution: SOx, NOx, PM, VOCs.

Semantic code11.102

Substance.Water-Stewardship

Object Classesobject class

Water in any state relevant to water stewardship reporting: freshwater, wastewater, recycled water.

Semantic code11.103

Information-Set

Object Classesobject class

A collection of information, whether in physical form (such as a book), machine-readable form (such as a file on disc), or human memory.

Semantic code12

Information-Set.Emission-Report

Object Classesobject class

A structured report of emission data for a reporting period, conformant to a reporting framework.

Semantic code12.101

Information-Set.Audit-Trail-Record

Object Classesobject class

An immutable record documenting data lineage, transformation history, and custody chain.

Semantic code12.102

Information-Set.Conservation-Check

Object Classesobject class

A reconciliation record verifying mass-balance or ledger conservation (e.g., e-liability totals match).

Semantic code12.103

Information-Set.Reporting-Period

Object Classesobject class

A defined time interval for which emission data is collected and reported.

Semantic code12.104

Information-Set.Emission-Factor

Object Classesobject class

Reference information carrying emission conversion factors and their sources, used to derive emission quantities from activity data.

Semantic code12.105

Information-Set.Unit-Reference

Object Classesobject class

Reference information defining units of measure, unit systems, physical quantity kinds, and currencies used to express measured or monetary values.

Semantic code12.106

Information-Set.Emission-Inventory

Object Classesobject class

A structured inventory of emission sources and quantities for an organization or facility, organized by category for reporting.

Semantic code12.107

Service

Object Classesobject class

A valuable potential or actual action, deed, or effort to satisfy a need or to fulfill a demand.

Semantic code13

Service.Independent-Verification

Object Classesobject class

A third-party or internal service providing independent assurance of emission data.

Semantic code13.101

Service.OFP-Data-Ingestion

Object Classesobject class

A service that ingests, transforms, and maps raw data to the OFP Recording Domain.

Semantic code13.102

Service.Sustainability-Assurance

Object Classesobject class

A service providing formal assurance or attestation of sustainability reports and organizational boundaries.

Semantic code13.103

Trader

Rolesrole

Any role derived from any kind of trade relation of the implied or referenced object.

Semantic code1

Trader.Emitter

Rolesrole

An entity that produces greenhouse gas emissions and holds the resulting e-liability.

Semantic code1.101

Trader.Offsetter

Rolesrole

An entity that generates or purchases carbon offsets/credits to compensate for emissions.

Semantic code1.102

Trader.Supplier

Rolesrole

A supply chain partner providing embedded emission data for Scope 3 upstream categories.

Semantic code1.103

Trader.Customer

Rolesrole

The party that buys a product, service or resource and inherits the emissions embedded in it; the buyer-side counterpart of Trader.Supplier. On the customer's books the same emission value a supplier reports as its own becomes upstream (Scope 3) emissions, so one value carries a supplier-role code on one side of a transaction and a customer-role code on the other without being re-keyed.

Semantic code1.104

Lineage

Rolesrole

Any role derived from a relationship of the implied or referenced object with a common heritage.

Semantic code2

Lineage.Emission-Provenance-Chain

Rolesrole

The provenance chain tracing emission data from measurement point through processing to final report.

Semantic code2.101

Lineage.Product-Supply-Chain

Rolesrole

The supply chain lineage of embodied carbon through product life-cycle stages.

Semantic code2.102

Organized-Structure

Rolesrole

Any role derived from the configurational/organizational relation of an object.

Semantic code3

Organized-Structure.Reporting-Hierarchy

Rolesrole

An organizational hierarchy defining the reporting boundary (equity share, operational control, financial control).

Semantic code3.101

Organized-Structure.Address

Rolesrole

A postal or physical address structure within an organizational entity.

Semantic code3.102

Organized-Structure.Contact

Rolesrole

A contact person or point of contact within an organizational entity.

Semantic code3.103

Citizenship

Rolesrole

Any role derived from nationality of an implied or referenced person object.

Semantic code4

Proxy

Rolesrole

Any role derived from a kind of intermediation on behalf of an implied or referenced object.

Semantic code5

Proxy.Emission-Factor

Rolesrole

A proxy value used to convert activity data into estimated GHG emissions when direct measurement is unavailable.

Semantic code5.101

Proxy.Estimated-Value

Rolesrole

An estimated quantity derived from proxy data, models, or extrapolation rather than direct measurement.

Semantic code5.102

Proxy.Aggregation

Rolesrole

An aggregated or rolled-up value derived from detail-level records.

Semantic code5.103

Target

Rolesrole

Any role derived from a treatment with the intent to change an implied or referenced object.

Semantic code6

Target.Reduction-Goal

Rolesrole

A defined emissions reduction goal (SBTi-aligned, net-zero, absolute/intensity target).

Semantic code6.101

Target.Compliance-Threshold

Rolesrole

A regulatory threshold or cap that must not be exceeded (EU ETS allocation, EPA limits).

Semantic code6.102

Capability

Rolesrole

Any role derived from an acquired, trained, tuned, configurated or calibrated capability of an implied or referenced object.

Semantic code7

Capability.Emissions-Measure

Rolesrole

The ability to directly measure emissions via instruments (CEMS, flow meters, gas analysers).

Semantic code7.101

Collectiveness

Rolesrole

Any role derived from collective characteristics of implied or referenced objects.

Semantic code8

Collectiveness.Scope-Individual-Emissions-Aggregation

Rolesrole

The aggregation of individual emission records into Scope 1, 2, or 3 totals.

Semantic code8.101

Collectiveness.Portfolio-Multiple-Entities-Emissions-Aggregation

Rolesrole

The aggregation of emissions across multiple entities, facilities, or products into portfolio-level totals.

Semantic code8.102

Leveragability

Rolesrole

Any role derived from leveragability of an implied or referenced object.

Semantic code9

Leveragability.Intensity-Ratio

Rolesrole

A ratio expressing emission intensity relative to a business metric (revenue, production volume, FTE).

Semantic code9.101

Classifier

Rolesrole

The member acts as a controlled classification value - a type, category, status, or scheme entry - that categorizes instances of its object class rather than being an instance itself.

Semantic code10

Identifier

Propertiesproperty

A value that is intended to identify uniquely the object of the data element.

Semantic code1

Identifier.External

Propertiesproperty

An identifier originating from an external system, registry, or partner.

Semantic code1.101

Identifier.Reference

Propertiesproperty

A foreign key reference to another entity within the OFP data model.

Semantic code1.102

Name

Propertiesproperty

A word or phrase that refers to the object of the data element but is not intended to identify it uniquely.

Semantic code2

Code

Propertiesproperty

A value from an enumerated list of possible values that is not an Indicator and that is not subject to continual change.

Semantic code3

Code.Emissions-Scope

Propertiesproperty

A code categorizing emissions into Scope 1 (direct), Scope 2 (energy indirect), or Scope 3 (other indirect).

Semantic code3.101

Code.Emissions-Data-Quality

Propertiesproperty

A code representing data quality along PACT DQI dimensions (temporal, geographical, technological, reliability, coverage).

Semantic code3.102

Code.ESG-Governance

Propertiesproperty

A code representing ESG governance metrics (board diversity, policy compliance, anti-corruption).

Semantic code3.103

Code.Social-Performance

Propertiesproperty

A code representing social performance metrics (workforce safety, diversity, training, living wage).

Semantic code3.104

Code.Entity-Category

Propertiesproperty

A code classifying an entity into a type or category from a controlled vocabulary.

Semantic code3.105

Code.Lifecycle-Status

Propertiesproperty

A code representing the lifecycle or workflow status of an entity.

Semantic code3.106

Code.Verification-Status

Propertiesproperty

A code representing the verification or assurance status of a data element or report.

Semantic code3.107

Indicator

Propertiesproperty

A value that is one of only two (true or false) possible choices.

Semantic code4

Measure

Propertiesproperty

A numeric quantity that has an explicit or implied unit of measure other than a monetary unit.

Semantic code5

Measure.Greenhouse-Gas-Emission

Propertiesproperty

A measure of greenhouse gas emissions in a CO2-equivalent unit (kgCO2e, tCO2e), whether measured, calculated or estimated — the recording method is carried by Emission Recording Method Type, not by this property (the MRV 'measure'). Aggregates and footprint totals use this member; origin-specific values use its leaves.

Semantic code5.101

Measure.Greenhouse-Gas-Emission.Fossil

Propertiesproperty

Greenhouse-gas emissions of fossil origin — fuel combustion, fugitive and process emissions, including fossil emissions arising from land management — in a CO2-equivalent unit.

Semantic code5.101.101

Measure.Greenhouse-Gas-Emission.Biogenic

Propertiesproperty

Greenhouse-gas emissions of biogenic origin — biogenic CO2 from land management and from the oxidation, transformation or degradation of biomass, and biogenic non-CO2 gases such as CH4 — in a CO2-equivalent unit. Removals are recorded separately under Removal.

Semantic code5.101.102

Measure.Greenhouse-Gas-Emission.Land-Use-Change

Propertiesproperty

Emissions from carbon-stock loss due to land conversion, such as deforestation or conversion of natural forest to plantation, in a CO2-equivalent unit; the direct and indirect cases are distinguished below.

Semantic code5.101.103

Measure.Greenhouse-Gas-Emission.Land-Use-Change.Direct

Propertiesproperty

Direct land-use change (dLUC): emissions from carbon-stock loss on land converted for the product's own supply chain, typically assessed over the preceding 20 years.

Semantic code5.101.103.101

Measure.Greenhouse-Gas-Emission.Land-Use-Change.Indirect

Propertiesproperty

Indirect land-use change (iLUC): emissions from carbon-stock loss on land converted elsewhere as a market consequence of the product's demand; usually reported separately from the footprint total.

Semantic code5.101.103.102

Measure.Greenhouse-Gas-Emission.Removal

Propertiesproperty

Greenhouse gas removed from the atmosphere or withdrawn into the product, in a CO2-equivalent unit, reported separately from emissions; biogenic and technological removals are distinguished below.

Semantic code5.101.104

Measure.Greenhouse-Gas-Emission.Removal.Biogenic

Propertiesproperty

Biogenic removals: temporary CO2 uptake by biomass contained in the product at the factory gate, biogenic carbon withdrawal, and removals from a net increase in land-based carbon pools.

Semantic code5.101.104.101

Measure.Greenhouse-Gas-Emission.Removal.Technological

Propertiesproperty

Technological removals: CO2 captured directly from the atmosphere or via biogenic CO2 capture and storage, subject to permanence and reporting requirements.

Semantic code5.101.104.102

Measure.Greenhouse-Gas-Emission.Leakage

Propertiesproperty

Emissions displaced outside the value chain as a consequence of the product's land use (land carbon leakage), reported separately from the footprint.

Semantic code5.101.105

Measure.Greenhouse-Gas-Emission.Partial

Propertiesproperty

A greenhouse-gas emission measure scoped to one life-cycle stage or activity of the footprint — packaging, outbound logistics, aircraft transport — in a CO2-equivalent unit; the stage or activity is identified by the field's entity or reference, not by a further property.

Semantic code5.101.106

Measure.Water-Volume

Propertiesproperty

A measure of water volume (withdrawal, discharge, consumption) in cubic metres or equivalent.

Semantic code5.102

Measure.Biodiversity-Index

Propertiesproperty

A measure of biodiversity status or impact (MSA, BII, species richness index).

Semantic code5.103

Measure.Spatial

Propertiesproperty

A spatial coordinate, distance, or geometric measurement.

Semantic code5.104

Quantity

Propertiesproperty

An integral numeric quantity that has no unit of measurement.

Semantic code6

Quantity.Greenhouse-Gas-Emissions

Propertiesproperty

The total quantity of greenhouse gas emissions for a given activity, period, and scope. Superseded for emission values by 5.1 Measure.Greenhouse-Gas-Emission and its leaves — an emission value is a measure with a CO2e unit — and retained for compatibility only, with retirement proposed for the next major version. Activity data remain under 6.2.

Semantic code6.101

Quantity.Emissions-Activity-Drivers

Propertiesproperty

The quantity of an activity driver (kWh consumed, litres fuel burned, km travelled) used in emission calculations.

Semantic code6.102

Amount

Propertiesproperty

An explicit or implied monetary unit of measure.

Semantic code7

Amount.Carbon-Amount

Propertiesproperty

A monetary or physical amount specifically associated with carbon (carbon price, carbon tax, carbon credit value).

Semantic code7.101

Amount.Ledger

Propertiesproperty

A monetary or quantitative amount in a ledger context (balance, debit, credit).

Semantic code7.102

Rate

Propertiesproperty

A real numeric quantity, possibly expressed as a fraction, but not as a percentage.

Semantic code8

Rate.Greenhouse-Gas-Emission

Propertiesproperty

The rate of greenhouse gas emission per unit time (kg/hr, t/year) or per unit activity (kgCO2e/kWh).

Semantic code8.101

Percent

Propertiesproperty

A numeric quantity expressed as a percentage. Percent is a specialized Rate.

Semantic code9

Percent.Emissions-Reduction

Propertiesproperty

The percentage reduction of emissions relative to a baseline year or reference scenario.

Semantic code9.101

Date

Propertiesproperty

A specific date in the progression of time.

Semantic code10

Date.Period-Start

Propertiesproperty

The start date of a reporting, validity, or observation period.

Semantic code10.101

Date.Period-End

Propertiesproperty

The end date of a reporting, validity, or observation period.

Semantic code10.102

Date.Validity-Start

Propertiesproperty

The start date of a validity or applicability window for factors, rules, or registrations.

Semantic code10.103

Date.Validity-End

Propertiesproperty

The end date of a validity or applicability window for factors, rules, or registrations.

Semantic code10.104

Date-Time

Propertiesproperty

A specific date plus time in the progression of time.

Semantic code11

Date-Time.Effective

Propertiesproperty

The date-time when a record, rule, or status becomes effective.

Semantic code11.101

Date-Time.Termination

Propertiesproperty

The date-time when a record, rule, or status ceases to be effective.

Semantic code11.102

Time

Propertiesproperty

A specific time within a specific timeframe.

Semantic code12

Text

Propertiesproperty

Text that is not an identifier, name, code, indicator, measure, quantity, amount, rate, percent, date, date-time, or time.

Semantic code13

Text.Description

Propertiesproperty

Descriptive free text providing context about an entity or record.

Semantic code13.101

Text.Formula

Propertiesproperty

A textual formula, rule expression, or calculation specification.

Semantic code13.102

Text.Comment

Propertiesproperty

A free-text annotation, reviewer note, or explanatory comment.

Semantic code13.103

Binary

Propertiesproperty

A value that is not an identifier, name, code, indicator, measure, quantity, amount, rate, percent, date, date-time, time, or text.

Semantic code14

Semantic Layer API

The ontology is not just documentation — it is served as a semantic layer for cross-system alignment. Connectors and agents can look up the canonical meaning of a field, discover which fields share a semantic code, and map external data to Open Footprint without guesswork.

Cross-system alignment

A source-system field (e.g., SAP Material Group) can be related to its canonical counterpart (e.g., CPC Code) through a shared O-DEF semantic code, even when the names and formats differ.

GET /api/v1/ofp/semantics
GET /api/v1/ofp/semantics/{code}

Model-wide annotations

Every entity response carries field.odef data, and the semantic layer exposes which of the 660+ annotated fields share each code, complete with field-count cautions to avoid mapping onto noise.

Semantic Grounding Chain

O-DEF RegistryOFP AnnotationSemantic CodeSemantic APICross-System Map

The approved O-DEF registry annotates every Open Footprint data element with a 3-axis semantic code. That code is exposed through the semantic layer API so external systems — ERP, LCA tools, satellite pipelines — can map to the canonical model with confidence.

Alignment Ontologies

QUDT, SOSA, PROV-O, GeoSPARQL, and FIBO mappings from the O-DEF grounding chain.

Explore

Units of Measure

Energistics UoM as system of record, QUDT as its RDF face in the knowledge graph.

Explore

Semantic API

Natural-language and programmatic access to verified emissions data and model validation.

Explore