One GHG Inventory for Reporting Teams: Make GRI and ISSB Work Together

GRI serves stakeholders who need to understand an organization's impact on people and the planet, while ISSB, through IFRS S1 and S2, serves investors who need financially material information for capital decisions. The two are not competing systems. Most organizations that report under ISSB also reference GRI, and climate disclosures are the clearest place where the same data set can satisfy both.

TL;DR:

• Check jurisdictional mandates first: IFRS Sustainability Disclosure Standards or CSRD and ESRS set the reporting floor, and European rules may require both materiality lenses.
• Use one GHG Protocol inventory for Scope 1, 2, and 3 emissions, then add GRI’s market based Scope 2 and biogenic CO2 disclosures and ISSB’s distinct industry metrics and breakdowns.
• GRI materiality work draws on communities, employees, and NGOs, while ISSB teams must connect sustainability measures to financial statements and document uncertainty.
• Sequence dual reporting by assessing materiality, agreeing on shared metrics, then preparing assurance records and a single evidence file for each disclosure topic.

Table of Contents

• GRI vs ISSB at a glance
• What GRI standards actually require
• What ISSB and IFRS S1/S2 require
• How the differences change what you must collect
• Where GRI and IFRS S2 line up on emissions
• When to use GRI, ISSB, or both
• A practical checklist for dual-framework alignment
• Why treating these as complementary lenses works better
• Build the capability to report under both frameworks
• FAQ
• Sources

GRI vs ISSB at a glance

Reporting teams juggling both frameworks usually want one question answered first: which standard governs which decision. The short version is that GRI asks "what is our effect on the world," and ISSB asks "what does an investor need to know about risk and value." Scope and adoption patterns follow from that split.

• GRI tends to drive the content of a standalone sustainability report.
• ISSB tends to drive what shows up alongside, or inside, financial statements.
• Many organizations treat GRI as the broader narrative and ISSB as the investor-grade subset.

What GRI standards actually require

The GRI framework exists for organizations that want to communicate their impact on the economy, environment, and people to a wide stakeholder base, not just shareholders. It is built as a modular system: Universal Standards apply to every reporter, Sector Standards address industry-specific issues, and Topic Standards cover specific subjects like emissions, labor practices, or water use.

GRI's impact materiality process asks an organization to map its stakeholders, then identify which topics matter most to those groups based on actual or potential effects, whether positive or negative. That process typically produces a materiality matrix and a published content index showing where each disclosure lives in the report.

Practitioners preparing a GRI-aligned report will typically work through:

• GRI 2 (General Disclosures) for governance and organizational context.
• GRI 305 (Emissions) for Scope 1, 2, and 3 greenhouse gas data.
• GRI 401, 403, and 405 for labor, health and safety, and diversity metrics.
• Sector Standards where applicable, such as oil and gas or coal.

What ISSB and IFRS S1/S2 require

ISSB standards exist to give investors decision-useful information about sustainability-related risks and opportunities that could reasonably affect an entity's cash flows, access to finance, or cost of capital over the short, medium, and long term. IFRS S1 sets the general disclosure requirements and defines materiality in financial terms, tied to what a reasonable investor would consider relevant to capital allocation decisions.

IFRS S2 narrows in on climate, requiring disclosure of governance, strategy, risk management, and metrics and targets related to climate risk. For greenhouse gas measurement, ISSB requires use of the GHG Protocol Corporate Standard for Scope 1, 2, and 3 emissions, which is the same measurement base GRI 305 relies on.

To identify which industry-specific metrics matter, reporting teams consult the ISSB industry-based guidance, built on SASB's sector framework. Because ISSB disclosures sit close to financial statements, teams must:

• Tie sustainability metrics to figures already in the financial statements.
• Disclose connected uncertainty and judgment, not just outcomes.
• Prepare for assurance expectations similar to financial audit.

How the differences change what you must collect

The conceptual gap between impact materiality and financial materiality is not academic. It changes who you interview, what thresholds you apply, and which numbers end up disaggregated.

1. Stakeholder scope widens under GRI. A GRI materiality process pulls in community representatives, NGOs, and employees, while an ISSB assessment centers on investor and lender perspectives.
2. ISSB is more prescriptive on specific metrics. IFRS S2 requires defined climate metrics and industry-based guidance, while GRI gives more latitude on exactly how a topic is quantified within its Topic Standards.
3. Measurement choices diverge at the margins. GRI 305 asks for both market-based and location-based Scope 2 figures and a separate biogenic CO2 disclosure, while IFRS S2 has its own disaggregation requirements that do not map one for one onto GRI's categories, according to IFRS interoperability guidance.
4. Regulatory triggers differ by jurisdiction. The European Union's CSRD and its ESRS incorporate elements of both impact and financial materiality, a dynamic explained in our piece on double materiality under ESRS, meaning an organization caught by CSRD may need to satisfy a third, hybrid logic on top of GRI and ISSB.

Pro Tip: Build your GHG inventory once, using the GHG Protocol Corporate Standard, then layer GRI-specific and IFRS S2-specific disaggregation on top rather than running two separate data pulls.

Where GRI and IFRS S2 line up on emissions

IFRS and GRI issued a joint statement committing to interoperable reporting and identifying common disclosures so entities are not forced to duplicate effort across both sets of standards. That commitment matters most in greenhouse gas reporting, where GRI 305 and IFRS S2 show a high degree of alignment on gross Scope 1, Scope 2, and Scope 3 emissions expressed in CO2 equivalent.

• A single GHG inventory built on the GHG Protocol Corporate Standard covers the core of both frameworks.
• GRI reporters add market-based Scope 2 and the biogenic split on top of that base.
• ISSB reporters add the disaggregation and industry-based metrics that connect emissions to financial risk.

When to use GRI, ISSB, or both

The decision rarely comes down to preference. It comes down to who is asking and what law applies.

1. Check for a regulatory mandate first. If your jurisdiction requires IFRS Sustainability Disclosure Standards or CSRD/ESRS, that sets your floor regardless of stakeholder preference.
2. Assess investor demand. Public companies with institutional shareholders increasingly face direct requests for ISSB-aligned climate data.
3. Weigh stakeholder expectations. Organizations with strong community, NGO, or supply chain scrutiny often keep GRI even where it is not mandatory.
4. Sequence the work. Run materiality assessment first, then settle on common metrics, then build toward assurance readiness, rather than tackling all three at once.

Many organizations end up running both: ISSB for the investor-facing filing, GRI for the broader stakeholder report, with a shared GHG inventory underneath both.

A practical checklist for dual-framework alignment

Reducing duplicate work starts with mapping, not with drafting two separate reports from scratch.

• Map each material topic to both its stakeholder relevance and its potential investor risk.
• Build the GHG inventory once on the GHG Protocol Corporate Standard so it feeds GRI 305 and IFRS S2 together.
• Use ISSB industry-based guidance to select sector metrics instead of building a custom metric set from scratch.
• Document every materiality judgment and measurement choice before assurance review begins, since both internal sign-off and external assurance will ask for that trail.

Pro Tip: Keep a single evidence file per disclosure topic that shows which framework it satisfies and why, so assurance providers are not chasing down the same data twice.

Why treating these as complementary lenses works better

Organizations that frame GRI and ISSB as a choice tend to under-invest in one or the other and end up redoing work when a regulator or investor group asks for what they skipped. The more durable approach treats GRI as the wide-angle lens on impact and ISSB as the zoom lens on financial risk, built from a shared data core.

The gap most teams underestimate is not conceptual, it is operational: staff who can run an impact materiality process rarely have the same fluency in linking metrics to financial statements, and vice versa. Closing that gap takes a short internal gap analysis, an executive briefing on where mandates apply, and targeted training for the people who will actually prepare and defend the disclosures.

— Ransford

Build the capability to report under both frameworks

Our certification pathways aim to address the challenges reporting teams face when GRI and ISSB requirements coincide. Our Mastering IFRS S1 & S2 Sustainability Reporting course walks through investor-facing climate disclosure requirements, while our Certificate in Sustainability Reporting builds the GRI-side skills for stakeholder materiality and content indexing.

• Learn to map material topics to both impact and financial risk in one process.
• Work with sector metrics drawn from ISSB industry-based guidance.
• Build assurance-ready documentation habits from day one.

For teams that want to continue access across multiple courses as standards evolve, our All-Access CPD Pass covers IFRS S1 and S2, carbon accounting, and board-level ESG governance in one subscription. Enroll through our course catalog to start self-paced or join an instructor-led cohort.

FAQ

What is the difference between GRI and ISSB?

GRI reports on an organization's impact on the economy, environment, and people for a broad stakeholder audience, while ISSB, through IFRS S1 and S2, reports on sustainability-related risks and opportunities relevant to investors. The two use different materiality tests, impact versus financial, but cover overlapping ground on greenhouse gas emissions.

Is GRI still relevant now that ISSB exists?

Yes. Industry reporting indicates that 80% of companies using ISSB Standards also reference GRI, which shows the two frameworks operating alongside each other rather than one replacing the other.

What are the big four ESG standards organizations?

Definitions vary across commentators, but the frameworks most commonly discussed together are GRI, ISSB (which absorbed SASB's industry-based guidance), the EU's ESRS under CSRD, and CDP for environmental disclosure. Coverage and mandates differ by jurisdiction, so check which ones apply to your organization before assuming a universal list.

What are the three types of GRI standards?

GRI Standards are organized into Universal Standards, which apply to every reporting organization, Sector Standards, which address industry-specific topics, and Topic Standards, which cover individual subjects such as emissions or labor practices. A reporter typically combines all three to build a complete disclosure.

How do I choose between GRI and ISSB for my organization?

Start by checking whether a regulator in your jurisdiction mandates IFRS Sustainability Disclosure Standards or CSRD, since that sets a floor regardless of preference. Layer in investor demand and stakeholder expectations next, and where both apply, build your greenhouse gas inventory once using the GHG Protocol Corporate Standard to serve both frameworks.

Sources

• Interoperability considerations for GHG emissions when applying GRI Standards and ISSB Standards
• Why leading organisations are using both GRI and ISSB - BDO

Recommended

• Stop Duplicate ESG Data: Reporting Teams' Plan for GRI and SASB
• GHG Protocol Scopes: Reporting Teams Must Know 2025–2026 Changes
• Four Pillars of IFRS S2: Practical Steps for Reporting Teams
• TCFD to ISSB: What Changes for Climate Reporting