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Accounting for climate impact and action is just a special case of impact accounting. We aim to make our ontology as generic as possible so that it can be applied to all forms and fields of impact accounting (i.e., to all SDGs).


Our ontology currently comprises 23 classes and 17 axioms.


  • thing
    • role
      • auditor
      • calibrator
      • claimant
      • developer
      • operator
      • owner
    • resource
    • period
      • accounting period
      • crediting period
      • project period
    • parameter
    • instrument
      • measurement instrument
    • input
    • indicator value
    • expression symbol
    • event
    • coordinate reference system
    • control
    • activity class
    • activity
      • audit
      • claim act
      • measure
    • agent
      • natural person
      • legal person
    • calculation
    • claim
      • impact claim
    • difference in state
    • environment
    • formula
    • impact pathway position
      • driver ipp
      • state ipp
      • effect ipp
      • exposure ipp
    • indicator
    • location
      • line
      • path
      • point
      • polygon
      • volume
    • output
    • reputation
    • variable
    • state


  1. An agent engages in an activity.
  2. An activity impacts an environment.
  3. An environment is defined by (interrelated) parameters.
  4. A state is the value of a parameter P at time t.
  5. An activity is performed with an instrument.
  6. An activity has at least one input.
  7. An activity has at least one output.
  8. To claim (v) is to ...
  9. To report (v) is to ...
  10. To verify is to ...
  11. To audit (v) is to ...
  12. To measure is to ...
  13. A claim is a statement about a (some specific) thing.
  14. A report is ...
  15. An agent enacts a role.
  16. An owner (role) is an agent who owns some specific thing.
  17. An operator (role) is an agent who operates some specific instrument.
  18. A developer (role) is an agent who ...
  19. A claimant (role) is an agent who makes a claim.
  20. A verifier (role) is an agent who verifies a claim.
  21. An auditor (role) is an agent who audits a claim.
  22. An event impacts an environment.
  23. A control limits or directs a thing.



FINAL: "Anything perceivable or conceivable." ("object" - ISO 9000:2015(E))

"An entity is a physical, digital, conceptual, or other kind of thing with some fixed aspects; entities may be real or imaginary." (

object, entity, item"Every individual in the OWL world is a member of the class owl:Thing. Thus each user-defined class is implicitly a subclass of owl:Thing."[1]

FINAL: A claim is a statement about a (some specific) thing.

"[A]n assertion that something is true." (OED, Google)


A report is a claim.



FINAL: "An agent is something that bears some form of responsibility for an activity taking place, for the existence of an entity, or for another agent's activity." (

"[A] person or thing that takes an active role or produces a specified effect." (OED, Google)

"[The] doer of an action, typically expressed as the subject of an active verb or in a by phrase with a passive verb." (OED, Google)

'organization' as defined in ISO's Annex SL Appendix 2 is treated in this ontology as an agent consisting of multiple other agents.

Think further about delegation.

foaf has: The foaf:Agent class is the class of agents; things that do stuff. A well known sub-class is foaf:Person, representing people. Other kinds of agents include foaf:Organization and foaf:Group.


FINAL: A thing that an agent does, which impacts an environment.

"[A] thing that a person or group does or has done." (OED, Google)

"Smallest identified object of work in a project." (ISO 9000:2015(E))

"An activity is something that occurs over a period of time and acts upon or with entities; it may include consuming, processing, transforming, modifying, relocating, using, or generating entities." (


FINAL: The activity of ascertaining the value of a parameter defining a state.

"[A]scertain the size, amount, or degree of (something) by using an instrument or device marked in standard units." (OED, Google)

"[A]ssess the importance, effect, or value of (something)." (OED, Google)

monitor (?)"[D]etermining the status of a system, a process, a product, a service, or an activity." ("monitoring" - ISO 9000:2015(E))

FINAL: The activity of making a statement about a (specific) thing.

"[S]tate or assert that something is the case..." (OED, Google)

"[A]ssert that one has gained or achieved (something)." (OED, Google)


W3C Glossary: (n.) Assertion (i) Any expression which is claimed to be true. (ii) The act of claiming something to be true. is practically identical: "A claim is a statement about a subject. A subject is a thing about which claims can be made."



FINAL (proposed): The activity of making sure or demonstrating that something is true, accurate, or justified.

"[M]ake sure or demonstrate that (something) is true, accurate, or justified." (OED, Google)

"[C]onfirm[], through the provision of objective evidence, that specified requirements have been fulfilled." ("verification" - ISO 9000:2015(E))

"[T]o establish the truth, accuracy, or reality of." (Merriam-Webster)

validateISO 9000 defines 'verification' and 'validation' indistinguishably.


"[C]onduct a systematic review of." (OED, Google)

Conduct a systematic review or assessment of something.

"systematic, independent and documented process for obtaining objective evidence and evaluating it objectively to determine the extent to which the audit criteria are fulfilled" ("audit" - ISO 9000:2015(E))


FINAL (proposed): The surroundings and conditions in which a thing exists.

"[T]he surroundings or conditions in which a person, animal, or plant lives or operates." (OED, Google)

"[T]he setting or conditions in which a particular activity is carried on. (OED, Google)

"[A] specified sphere of activity or knowledge." ("domain" - OED, Google)

domain (?)

A numerical or other measurable quality or feature forming one of a set that defines a thing or sets the conditions of its existence or operation.

"[A] numerical or other measurable factor forming one of a set that defines a system or sets the conditions of its operation." (OED, Google)

"[A] limit or boundary which defines the scope of a particular process or activity." (OED, Google)

"[A] numerical characteristic of a population, as distinct from a statistic of a sample." (OED, Google)

"[A] quality or feature regarded as a characteristic or inherent part of someone or something." ("attribute" - OED, Google)


A state is the value of a parameter P at time t.
(Perhaps try to get to a definition that does not involve the term "time", unless we define "time" itself too.)

"[T]he particular condition that someone or something is in at a specific time." (OED, Google)

"Condition" in the sense of "if x then..." are expressed by using thing:state inside thing:control. Definitions for "condition": {

  1. "[A] situation that must exist before something else is possible or permitted." (OED, Google)
  2. "[A]n arrangement that must exist before something else can happen." (Cambridge)
  3. "[A] premise upon which the fulfillment of an agreement depends." (Merriam-Webster)
  4. "[A] provision making the effect of a legal instrument contingent upon an uncertain event." (Merriam-Webster)
  5. "[S]omething essential to the appearance or occurrence of something else." (Merriam-Webster)
  6. "[A] restricting or modifying factor." (Merriam-Webster)



"[A] thing that happens or takes place,..." (OED, Google)

"[A] single occurrence of a process, e.g. the ionization of one atom." (OED, Google)

 A transition in the world (

"Events include generation, usage, or invalidation of entities, as well as starting or ending of activities...

An... event... happens in the world and marks a change in the world, in its activities and in its entities. The term 'event' is commonly used in process algebra with a similar meaning. Events represent communications or interactions; they are assumed to be atomic and instantaneous." (


"[T]he function assumed or part played by a person or thing in a particular situation." (OED, Google)

"[A] role is particular behaviour which a material entity may exhibit."


"A role is the function of an entity or agent with respect to an activity, in the context of a usage, generation, invalidation, association, start, and end." (

Roles are context-specific.
A role restricts the set of activities that an agent can perform in the context within which they enact the role.
Roles are sometimes mutually exclusive.
Some roles require the enacting agent to have met certain requirements to be allowed to enact the role in that context.


An agent who owns a thing.

"[A] person who owns something." (OED, Google)

A project owner is an agent who owns a project, with the project considered to be an instrument.

"[A] person who operates equipment or a machine." (OED, Google)

"[A] person or company that runs a business." (OED, Google)

A project operator is an agent who operates a project, with the project considered to be an instrument.
thing:role:claimant"[A] person making a claim, especially in a lawsuit or for a state benefit." (OED, Google)

thing:role:developer"[A] person or thing that develops something." (OED, Google)
How does 'project developer' differ from 'project owner' and 'project operator'?
thing:role:verifier"[S]omeone who vouches for another or for the correctness of a statement." ("verifier")


"[A] person who conducts an audit." (OED, Google)

"[P]erson who conducts an audit." (ISO 9000:2015(E))


"[A] means of limiting or regulating something." (OED, Google)

"[T]he restriction of an activity, tendency, or phenomenon." (OED, Google)

limit, regulation, constraint, guide(n),

directive, specification,



An impact accounting standard is a control that comprises both procedures and object specifications.

"standard": {

  1. "[A] level of quality or attainment." (OED, Google)
  2. "[A] required or agreed level of quality or attainment." (OED, Google)
  3. "[S]omething used as a measure, norm, or model in comparative evaluations." (OED, Google)
  4. "[P]rinciples of conduct informed by notions of honour and decency." (OED, Google)


requirement: {

  1. "[A] thing that is needed or wanted." (OED, Google)
  2. "[A] thing that is compulsory; a necessary condition." (OED, Google)
  3. "[N]eed or expectation that is stated, generally implied or obligatory." (ISO Annex SL Appendix 2)


constraint: {

  1. "[A] limitation or restriction." (OED, Google)
  2. "[S]omething that controls what you do by keeping you within particular limits." (Cambridge)
  3. "[A] constraining condition, agency, or force." (Merriam-Webster)
  4. "[A] restrictive condition." (Collins)


A procedure guides an activity.

procedure: {

  1. "[A]n established or official way of doing something." (OED, Google)
  2. "[A] series of actions conducted in a certain order or manner." (OED, Google)
  3. "[S]pecified way to carry out an activity or process." (ISO 9000:2015(E))


"methodology": {

  1. "[A] system of methods used in a particular area of study or activity." (OED, Google)


Methodology vs. procedure: {

  1. Option 1: "methodology" is a synonym for "procedure".
  2. Option 2: A methodology is a subclass of a procedure; hence narrower as a procedure.
  3. Option 3: A methodology is a thing:control that simply contains a procedure. 


An object specification is a control.

"[D]ocument stating requirements." ("specification", ISO 9000:2015(E))

"A plan is an entity that represents a set of actions or steps intended by one or more agents to achieve some goals." (

A condition limits an activity with reference to a state.


"[A] tool or implement, especially one for precision work." (OED, Google)

"[A] means of pursuing an aim." (OED, Google)

"[A] measuring device used to gauge the level, position, speed, etc. of something,..." (OED, Google)

"[A] thing made or adapted for a particular purpose, especially a piece of mechanical or electronic equipment." ("device" - OED, Google)

"[A] plan, method, or trick with a particular aim." ("device" - OED, Google)

"[A] device or implement, especially one held in the hand, used to carry out a particular function." ("tool" - OED, Google)

"[A] thing used to help perform a job." ("tool" - OED, Google)

device (?)

tool (?)


"[A] series of actions or steps taken in order to achieve a particular end." (OED, Google)

"[A] natural series of changes." (OED, Google)

"[A] systematic series of mechanized or chemical operations that are performed in order to produce something." (OED, Google)

"[S]et of interrelated or interacting activities that uses or transforms inputs to deliver a(n) (intended) result." (ISO Annex SL Appendix 2; ISO 9000:2015(E))


"[A]n individual or collaborative enterprise that is carefully planned to achieve a particular aim." (OED, Google)

"[A] proposed or planned undertaking." (OED, Google)

"[U]nique process, consisting of a set of coordinated and controlled activities with start and finish dates, undertaken to achieve an objective conforming to specific requirements, including the constraints of time, cost and resources." (ISO 9000:2015(E))

indicator"[A] thing that indicates the state or level of something." (OED, Google)
The difference between an indicator and a parameter depends on what the state is that you are interested in. In scenario Y, some indicators of scenario X are just parameters. 
objective"[R]esult to be achieved." (ISO Annex SL Appendix 2)goal

"[A] stock or supply of money, materials, staff, and other assets that can be drawn on by a person or organization in order to function effectively." (OED, Google)

"[A] source of help or information." (OED, Google)

"[A]vailable assets." (OED, Google)

input"[W]hat is put in, taken in, or operated on by any process or system." (OED, Google)

output"[R]esult of a process." (ISO 9000:2015(E))result

"[T]he beliefs or opinions that are generally held about someone or something." (OED, Google)

"[A] widespread belief that someone or something has a particular characteristic." (OED, Google)


Application of the ontology

TODO: this table is a work in progress and still needs A LOT of work.

Ontology (What are the 'things' that the accounting system should know about? What are the defining properties or characteristics of each 'thing'?)

Epistemology (How will the accounting system get information about these things and their attributes?)Semiology (How will each of the things be represented in the accounting system?)


  • unique identifier (identity)
  • type (individual or group; if group, what type of group, e.g. organisation, company or movement; auditor)
    • Develop or source a schema describing a minimum set of properties by agents type

An agent asserts their identity though digital signatures

Agents provide proofs of their properties through verified credentials 

Other parties can verify agent properties and make claims about their methods and results

Digital signature

Verified credentials 

Validation claim by third party



Definition "A role is particular behaviour which a material entity may exhibit."^^xsd:string


  • activity class (e.g. IPCC categories)
  • activity description including objective(s) 
  • location
  • start time
  • end time (possibly)
  • agent
  • input(s) (e.g. materials and energy; consumables and non-consumables)
  • process(es): a process links inputs to products and waste
  • output(s) product + waste
  • objective (experience, create, reduce, destroy, avoid, verify) (optional / not required in all instances)

* An audit is a special type of activity where the input is a claim and the output is an evaluation of that claim.

Ex ante: An agent asserts their intentions to act in a Projet Design Document (PDD) 

Ex post: An agent describe their actions in a Projet Design Document (PDD) 

The activity and its results and impacts are documented by the agent at intervals in a monitoring report (MR)

  • unique identifier

Consider a token for an activity that contains all the essential elements in column 1. Such a token must have a time limit and proof of life requirements (e.g. minimum process data feed to confirm it is ongoing)

NACE activity codes




  • location and temportal extent (either objective or referential)
  • definition (in terms of parameters of interest)


  • metrics referring to parameters
  • type (actual [measured] or baseline [counterfactual])

*State as in environmental state (not political state)

Parameters/indicators for states

Parameters/indicators delivered by agents via PDDs and MRs

  • unique identifier
  • impact claim per state
  • name
  • definition
  • unit of measure
  • rationale
  • calculation
  • credibility

(Emission factors are parameters, for example.)

  • unique identifier
  • name
  • author(s)
  • applicability - type of agent, type of activity, state
  • requirements (e.g. reporting requirements, calculation requirements)
  • version
  • method(s)
  • precision
  • accuracy / std error
  • emission factors (defaults)

  • unique identifier
  • agent 
  • activity
  • "before" state for every every environment and aspect of the state under consideration
  • "after" state for every every environment and aspect of the state under consideration
  • causal connection between activity and the resultant state (e.g. scope 1 (primary/secondary), scope 2 or scope 3)
  • standard followed


We know about things through direct participation in them or through representations. 

For things we experience directly we do not need any further assurance that they are true. 

Protobuf implementation (example)

UML diagram (hosted on Lucidchart; login required)


Hedera Hashgraph Guardian implementation (example)

(TODO: add files)

Code resources


TODOs and next steps:

  1. Complete the axioms for:
    1. claim (v)
    2. report (v)
    3. verify
    4. audit (v)
    5. measure
    6. report (n)
    7. developer
  2. Update the diagram with the latest axioms.
  3. Think about "attesting" and "attestation".
  4. Add a definition and example to each of the classes in Protégé. Also do it on this page.
  5. For discussion: Where do we list the natural processes that lead to climate change? Should there be an event class? An event is like an activity but without the intention of a HUMAN agent. An accident is an event but it is not an activity. 
  6. Expand the second and third… n levels of the ontology, as necessary.
    1. "sensor" and "actuator" are good candidates for subclasses to the "instrument" class. 
    2. What should the subclasses to thing:claim be? E.g., where would "measurement" fit in? Should we first distinguish between qualitative and quantitative claims? 
  7. Where do contracts fit in? thing:control?
  8. Align the ontology with OWL specifications and syntax.
  9. Incorporate the W3C's time ontology into our own ontology.
  10. Review PROV-O. How can we align our ontology with PROV-O?
  11. Embed ontology into BFO and its extensions. Some useful resources: BFO 6-part video series. Perhaps check if we should not rather go with AFO.
  12. See if we can use any of these ontologies for the spatial classes: W3C, DBpedia 
  13. Can we / should we try to align our ontology with ISDA CDM?
  14. Develop tools for applying the ontology (see our GitHub repo for what has already been done).
  15. Get industry entities to test our ontology & tools. Possible testers:
    1. SAP (
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