IFRS S2: Climate-related Disclosures·Paragraphs 29–a–iii
GHG measurement approach, inputs and assumptions
Guide pratique pour préparer cette information. Utilisez cette fiche pour identifier les données à préparer, vérifier les affirmations et organiser les preuves. Pour les exigences exactes, reportez-vous toujours à la source officielle IFRS.
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IFRS S2: Climate-related Disclosures
Paragraphs 29–a–iii · 2024
Dernière révision
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Support pédagogique LRA · Non publié ni approuvé par IFRS
Objet de l’information
This disclosure asks an organisation to explain the approach it uses to measure its greenhouse gas emissions, including the main inputs and assumptions behind those measurements. In practice, the focus is on showing how the numbers were built: what data was used, what estimation methods were applied, and where judgement or assumptions were needed to fill gaps or convert activity data into emissions figures.
The practical point is to make the measurement basis understandable and comparable, not just to present a final emissions total. An organisation should be clear about the scope of the approach across its operations, and whether the same method is used consistently or only for certain sites, business units or emission sources. The aim is to help users judge how robust and complete the reported emissions information is.
Ce support pédagogique LRA aide à préparer l’information. Pour les exigences exactes, reportez-vous toujours à la source officielle IFRS.
Avant de commencer
Avant de commencer
Une courte liste de contrôle avant de préparer cette information — cochez chaque point une fois réglé.
Préparation
Informations clés à préparer
| Champ à préparer | Ce qu’il faut recueillir | Indice de preuve | Responsable |
|---|---|---|---|
| Year-on-year changes | A clear note of what changed in the reported figure compared with the previous reporting year, including which parts of the calculation or coverage were updated. | Prior-year submission, current-year working papers, and a change log showing the revised basis. | Sustainability reporting / Finance |
| Boundary and consolidation basis | The rule used to decide which entities, sites, or activities are included in the reported total, and how that inclusion rule is applied in practice. | Group reporting policy, consolidation memo, organisational chart, and boundary mapping to the source data. | Finance / Sustainability reporting |
| Calculation factors used | The conversion or calculation factors applied to turn activity data into the reported result, including the source and version of each factor set. | Factor library, supplier or database extracts, calculation workbook, and version control records. | Sustainability reporting / Data analytics |
| Key inputs and assumptions | The main source inputs, estimates, and judgement calls used in the calculation, with enough detail to show what was measured, estimated, or assumed. | Source extracts, estimation notes, assumptions register, and calculation workbook comments. | Sustainability reporting / Operational data owners |
| Drivers of change | The specific operational or methodological reasons why the reported figure moved from the prior year, separated into real activity changes and calculation changes. | Variance analysis, management commentary, and supporting operational records for the main drivers. | Finance / Sustainability reporting |
| Scope 3 quality notes | Any short note on the reliability of the value chain data where it matters, including known gaps, estimates, or weak source data that affect confidence in the result. | Supplier data quality review, estimation log, gap analysis, and source-data assessment. | Sustainability reporting / Supply chain |
Comment le préparer
Demander les données
Request the emissions calculation pack from the carbon accounting owner
Traduisez l’information en une question métier interne, puis adaptez-la au vocabulaire de votre organisation.
What calculation approach, inputs, assumptions, and year-on-year changes were used to produce the greenhouse gas figures for this reporting period?
Use your organisation’s own names for the team, systems, and calculation packs first, then map them to the reporting disclosure. Keep the ask in everyday internal language rather than framework wording, and check the source material before sign-off.
Demande faible
Please provide the IFRS S2 GHG measurement approach, inputs and assumptions evidence for S2-29(a)(iii).
Pourquoi elle échoue : It uses framework language that many operational teams will not recognise, so the owner may not know which files or calculations to send. It also does not point to the practical artefacts needed to explain the numbers, such as the boundary, factors, assumptions, and year-on-year changes.
Meilleure demande
Please send the latest emissions calculation pack for [reporting period], including the boundary used, the source file or system extract, the factor set and version, the main inputs and assumptions, any changes since [prior period], and the reason for those changes. If you track indirect-emissions data quality, include those notes too.
Modèle d’e-mail formel
Subject: Request for the emissions calculation pack for [reporting period]\n\nHi [name/team],\n\nWe are preparing the sustainability reporting pack and need the calculation support behind the greenhouse gas figures for [reporting period].\n\nPlease send the latest version of your emissions calculation pack, including:\n- the boundary used for the inventory and any exclusions\n- the source file or system extract used to calculate the figures\n- the emission factor set and version/date\n- the main inputs and assumptions used in the calculations\n- any changes made since [prior period]\n- the reason for those changes\n- any notes on data quality for indirect emissions, where relevant\n\nIf it is easier, you can return this in your usual template or workbook. Please also include the period covered, the owner of the file, and the date it was last updated.\n\nThis is a possible LRA training template only; please adapt it to your organisation’s own terms and check the source material before sign-off.\n\nThanks,\n[preparer name]
Version courte pour Teams / Slack
Hi [name/team] — could you share the latest emissions calculation pack for [reporting period]? Please include the boundary, source file/system, factor set/version, key inputs and assumptions, any changes since [prior period], the reason for those changes, and any data-quality notes for indirect emissions if relevant. Use your usual format if easier. Thanks.
Exemples sectoriels
Manufacturing
Contexte. A plant-based group with fuel, electricity, refrigerants, and freight data held across site logs and a carbon workbook.
Demande adaptée. Please share the latest carbon workbook for [reporting period] covering the plant boundary, site list, fuel and power inputs, refrigerant assumptions, freight estimates, factor library version, and any changes since [prior period]. Include the reason for any restatements or methodology updates.
Exemple de réponse. Attached: carbon workbook v4.2; boundary note; site list; factor library v2025.1; assumptions tab; change log showing one new warehouse added and one freight proxy replaced; reason: improved meter coverage and updated logistics data.
Financial services
Contexte. A services group with office energy, business travel, purchased goods, and supplier estimates managed by sustainability and finance.
Demande adaptée. Please send the emissions calculation pack for [reporting period] used for the office and travel inventory, including the group boundary, source extracts, factor set, assumptions for supplier and travel estimates, and any changes from [prior period]. Add notes on any indirect-emissions data gaps or proxies.
Exemple de réponse. Attached: inventory model; boundary memo; travel extract; office energy file; factor register v3; assumptions log; change note showing a switch from estimated to booked travel data for one region; data-quality note: supplier spend-based estimates still used for one category.
Rédigez votre information
Des notes qui transforment les données en information publiée
Modèles pédagogiques LRA — adaptez-les à votre organisation et vérifiez la source officielle avant validation.
Note méthodologique
Explain the basis used to prepare the figures, including how the reporting boundary was defined, which inputs and assumptions were applied, and what conversion factors were used.
Note de contexte
Describe what the numbers represent in practice, including the effect of the chosen boundary, the main calculation inputs, and any quality limits that shape how the figures should be read.
Déclaration sur les variations
Set out the main reasons the figures changed from the previous year, distinguishing between real operational movement, changes in the reporting boundary, and updates to data or assumptions.
Entrée de l’index de contenu
s2-29-a-iii GHG measurement approach, inputs and assumptions — [location / page] / [notes]Centre de téléchargement
Outils et formulaires de préparation
Outils de préparation professionnels pour s2-29-a-iii — gratuits avec l’adhésion à LRA Community. Inscrivez-vous une fois (c’est gratuit) et tous les téléchargements se débloquent, avec la Bibliothèque des informations, les modèles et l’assistant IA LRA.
Préparation à l’assurance
Pour chaque affirmation, vérifiez les preuves
| Affirmation | Risque | Preuves à vérifier |
|---|---|---|
| We kept the coverage figure on the same basis as last year, and where we changed the basis we explained the effect clearly. | Assurer may test whether the year-on-year comparison is genuinely like-for-like, or whether a basis change has been hidden in the narrative. | Prior-year calculation file; current-year methodology note; reconciliation showing the effect of any basis change; draft-to-final review comments; sign-off confirming the comparison basis used. |
| We set out the practical method we used to build the figure, including the boundary we applied to the disclosed operations. | Assurer may probe whether the reported perimeter matches the entity’s chosen reporting boundary and whether any exclusions were deliberate and consistent. | Boundary memo; consolidation or operational control papers; list of included and excluded entities/sites; methodology paper; management approval of the boundary choice. |
| We explained why we used this approach, rather than another available method, for the disclosed figure. | Assurer may challenge whether the chosen approach was selected for convenience or to improve the result, rather than because it was the most suitable basis. | Method selection paper; options appraisal; internal emails or committee papers showing the rationale; approval records; consistency check against prior reporting decisions. |
| We described the data inputs and assumptions that fed into the calculation, so the reader can see what drove the result. | Assurer may look for missing assumptions, undocumented estimates, or inputs that were applied inconsistently across parts of the calculation. | Calculation workbook; assumption log; source data extracts; data dictionary; review notes showing each key input was traced and approved. |
| Where we changed the calculation basis, we explained what changed and why the update was made. | Assurer may test whether the explanation is complete, whether the change was intentional, and whether it has been applied consistently across the reporting period. | Change log; version history; revised methodology note; approval of the revised basis; comparison of old and new outputs showing the impact of the change. |
| For the supply-chain part of the figure, we noted the quality of the underlying data and how much came from detailed activity records or independently checked sources. | Assurer may question whether lower-quality estimates were presented as stronger evidence, or whether the mix of data types was properly disclosed. | Supplier data pack; activity-based input schedule; third-party verification statements where available; data quality assessment; summary of estimated versus directly sourced inputs. |
Dossier de preuves à préparer
Lacunes fréquentes dans les rapports
Lacunes fréquentes
Erreurs à éviter lors de la collecte des données
Là où un jugement professionnel est souvent nécessaire
Exemples
Exemples illustratifs
Synthétiques, rédigés par LRA — ils ne proviennent ni d’un rapport d’entreprise ni du texte d’une norme.
We have kept the same group perimeter as last year, with one small plant added after acquisition and no other boundary changes, so the year-on-year movement is mainly operational rather than structural.
- For the current year, we used the same calculation methods across the group and applied location-based electricity factors from our market data provider, plus supplier-specific factors where we had them for purchased materials and freight.
- The main shift came from higher output at our two largest sites and a fuller set of supplier data for upstream transport; our scope 3 figures remain partly estimate-based for categories where supplier coverage is still incomplete, so those numbers are less precise than our direct emissions data.
This example shows how to explain a stable reporting perimeter, the main drivers of movement, the factor sources used, the assumptions behind the numbers, and where indirect-emissions data still relies on estimates.
Our reporting boundary stayed unchanged this year and continues to follow the stores, warehouses and central functions we control, with franchise activity left outside the group totals.
- Compared with the prior period, the rise in our footprint was driven mainly by more customer deliveries and a larger electricity load in distribution centres; we used the same grid factors as last year, together with supplier data for leased vehicles where available.
- For indirect categories, we relied on spend-based estimates for a few upstream items and on activity data for logistics and waste; those areas are the least mature in our dataset, so we flag them as lower-quality inputs and expect future revisions as supplier coverage improves.
This example shows how to describe an unchanged boundary, explain the main reasons for movement, identify the factor set and input types used, and note where indirect-emissions data is still less robust.
Rapports d’entreprises
Comment les entreprises publient S2-29-a-iii en pratique
Exemples de pratiques de publication complètes et partielles. Ce sont des analyses fondées sur des preuves, non des modèles à recopier.
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Scénarios à travailler
A group has changed from using a market-based electricity factor to a location-based one for part of its footprint, and the emissions team also updated the boundary to include a newly controlled subsidiary from 1 July. The draft note currently says the numbers moved because of 'method updates' but does not separate the effects.
A preparer has used a mix of supplier-specific activity data, spend-based estimates, and default factors for purchased goods and freight. The working papers are complete, but the draft disclosure only lists the final tonnes and does not explain the main data sources or the assumptions behind the estimates.
A company has changed its emissions factor set during the year because it moved to a newer database for stationary fuel and refrigerants. The draft note mentions the new database name, but it does not say whether the change affected the current-year result or whether the prior-year figure was restated.
For Scope 3, the team has estimated several categories using secondary data because supplier data were incomplete. The draft disclosure says only that 'data quality is acceptable', even though some categories rely on broad industry averages and others on more specific shipment records.
Références au référentiel
Exigences IFRS / ISSB applicables et informations connexes
Références disponibles du référentiel et informations voisines utiles à la préparation de cette exigence.
IFRS / ISSB
s2-29-a-iii
au sein de IFRS S2 : Climate-related Disclosures
Connexes et exploration
Plus dans IFRS S2 → Parcourir le catalogue complet → Accueil de la Bibliothèque des informations → Rechercher dans toutes les informations →
FAQ
Questions auxquelles cette page répond
Start with the plain-language explainer, then work through the step-by-step preparation section and the datapoints list. The page is set up to help you move from source data to a draft disclosure and an assurance-ready evidence pack.
The page points you to year-on-year changes, the boundary and consolidation basis, calculation factors, key inputs and assumptions, drivers of change, and any Scope 3 quality notes. Use those as your minimum data checklist before drafting.
The page flags boundary and consolidation basis as a required datapoint to prepare, so you should document the scope you are using and keep that consistent through the draft and evidence pack. The workbook is there to help you capture that information in a structured way.
The page tells you to capture calculation factors used, key inputs and assumptions, and the drivers of change. That gives reviewers enough context to understand how the numbers were built and what changed year on year.
The page does not assign roles, but it is designed for sustainability/ESG managers, HR or data owners, and assurance reviewers to use together. In practice, ownership should sit with the people who can explain the source data, assumptions, and evidence behind the disclosure.
The page includes an evidence pack with five items to support assurance readiness, alongside six assurance claims to verify. Use those materials to show the claim, the risk, and the evidence trail for each point you are relying on.
The page has a section on common reporting gaps and mistakes, so it is worth checking your draft against that before sign-off. A practical way to use it is to compare your numbers, boundary, assumptions, and narrative against the page’s preparation checklist.
The Download Centre includes a Prep & Assurance workbook in .xlsx format and a printable Library Card in .pdf format. Use the workbook to organise the disclosure inputs and evidence, and the library card as a quick reference while drafting or reviewing.
Yes, but only as a synthetic illustration of how a draft can be structured. The example is there to show the style of narrative, the kind of table that may be useful, and how the content-index line can be written.
The page notes ESRS E1 (Climate Change) as the closest correspondence, which can help you think about reuse of data and supporting material. It does not say the requirements are identical, so treat it as a cross-reference rather than a one-to-one mapping.
Autres questions auxquelles cette page peut aider
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