GHG Protocol and ISO join forces:
What it means for corporate carbon accounting

If you asked one of our carbon accounting experts what industry news from 2025 has them most excited, chances are they’d mention the strategic partnership between the GHG Protocol and ISO announced last September. So what does this partnership actually mean—and why are your favorite carbon accounting nerds so fired up about it?

Table of contents

THE CORE CHALLENGE

The problem carbon accounting was built to solve

The late 1990s saw a wave of global interest in corporate responsibility, emerging alongside landmark international agreements like the Kyoto Protocol and the formation of the IPCC. As companies looked toward the new millennium, a broad acknowledgement was taking shape: the impact businesses have on the environment and the communities around them matters to their stakeholders, and in order to manage those impacts, you first have to measure them.

But measurement only works if everyone is using the same ruler.

With this collaboration between standards bodies, we may finally see the alignment that makes standardized measurement a global possibility across industries and business structures.

STANDARDS HISTORY

An evolution of carbon accounting methods

2001 — The GHG Protocol Corporate Standard
The GHG Protocol was born out of a straightforward problem: companies had no common standard for measuring and reporting greenhouse gas (GHG) emissions. In the late 1990s, the World Resources Institute (WRI) and World Business Council for Sustainable Development set out to change that. A 1998 WRI report, Safe Climate, Sound Business, helped crystallize the need for standardized measurement, and the two organizations quickly joined forces. By assembling an unlikely coalition of industry players like Shell and Norsk Hydro alongside environmental groups like WWF and the Pew Center on Global Climate Change, they built a multi-stakeholder process that produced the global benchmark for corporate GHG accounting. In 2001, the first GHG Protocol Corporate Standard was released.
2004 — Corporate Standard revised

The Corporate Standard was reviewed and republished in 2004. This is the version that remains in widespread use today. As of 2023, 97% of disclosing S&P 500 companies reported to CDP using the GHG Protocol.

2006 — ISO enters the picture

While the GHG Protocol was gaining traction, the International Organization for Standardization (ISO) was working in parallel. Beginning in 2002, ISO undertook a four-year process to develop its own standard, ISO 14064, defining how organizational GHG emissions should be measured, reported, and verified. Rather than competing with the GHG Protocol Corporate Standard, ISO 14064 was designed to be broadly compatible with it—giving organizations a third-party verifiable framework that complemented the Corporate Standard.

2011 — Expanding the scope

The GHG Protocol expanded its suite of standards with two major additions: the Corporate Value Chain (Scope 3) Standard, which addressed indirect emissions across a company’s entire value chain, and the Product Life Cycle Standard, which brought the same rigor to individual products and services.

2013–2015 — Calculation guidance for Scope 2 and 3

Detailed Scope 3 calculation guidance followed in 2013, giving companies actionable direction to tackle their most complex emissions categories. In 2015, GHG Protocol published its Scope 2 Guidance, establishing the now-familiar location-based and market-based carbon accounting methods for accounting for purchased electricity.

2018 — ISO 14064 technical revision

ISO completed a technical revision of the ISO 14064 series in 2018, modernizing the standard to reflect advances in GHG accounting practice and better align with the GHG Protocol’s evolving framework.

2022–2023 — Public consultation and new governance

For the first time in years, the GHG Protocol opened a comprehensive public consultation on its full suite of corporate standards. The process also prompted a governance restructure, with GHG Protocol establishing a new Steering Committee, Independent Standards Board, and Technical Working Groups to oversee future updates.

September 2025 — A landmark partnership

In September 2025, GHG Protocol and ISO announced a strategic partnership to harmonize their existing portfolios of GHG standards and co-develop new ones. The agreement covers the ISO 14064 family alongside the GHG Protocol Corporate, Scope 2, and Scope 3 Standards, and includes plans for a joint Product Carbon Footprint standard.

2027 — Updates on the horizon

Final revised versions of the Corporate Standard, Scope 2 Guidance, and Scope 3 Standard are expected by 2027, with harmonized ISO–GHG Protocol standards to follow.

WHAT’S CHANGING

Why this matters

For years, companies navigating carbon accounting methods have had to contend with two parallel frameworks that, while broadly compatible, weren’t fully aligned. That created friction—particularly for multinational organizations, those seeking third-party verification, or companies trying to satisfy multiple reporting requirements at once.

The GHG Protocol–ISO partnership is a significant step toward resolving that. Harmonized standards mean less ambiguity, more consistent data across industries, and a clearer path for companies to have their emissions figures independently verified. It’s also a signal that the field is maturing: carbon accounting is moving from a fragmented landscape of competing methodologies toward something more unified and durable.

PRACTICAL GUIDANCE

Navigating the transition

Standards updates of this scale don’t happen in a vacuum, and for companies with established carbon accounting programs, the 2027 revisions will likely prompt real questions. Will your current methodology still be compliant? How will the harmonized frameworks affect your Scope 3 reporting? What does this mean for 2030 reduction targets calculated in alignment with the current version of the standard?

The honest answer is: we don’t know yet. The GHG Protocol’s public consultation periods are still underway, and the partnership with ISO is in its early stages. The impact on companies reporting their emissions remains to be seen.

That’s where we come in. Our carbon accounting team stays at the leading edge of standards development so that when the landscape shifts, your program doesn’t have to scramble to catch up. Whether you’re building a carbon accounting program from scratch, preparing for third-party verification, or getting ahead of the 2027 updates, we can help you move forward with confidence.

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Contact Greenplaces today for a demo and discover how we can streamline your reporting journey.

Frequently asked questions

What is the GHG Protocol, and why is it the dominant carbon accounting standard?

The GHG Protocol Corporate Standard, first published in 2001 and revised in 2004, is the most widely adopted framework for measuring and reporting corporate greenhouse gas emissions. Its dominance comes from its multi-stakeholder development process, practical structure around Scope 1, 2, and 3 emissions, and broad adoption by reporting frameworks including CDP, SBTi, and CSRD. As of 2023, 97% of disclosing S&P 500 companies used it for CDP reporting.

ISO 14064 is an international standard developed by the International Organization for Standardization that defines how organizational GHG emissions should be measured, reported, and verified. It was designed to be broadly compatible with the GHG Protocol Corporate Standard, not to replace it. Together, they have functioned as complementary frameworks — with ISO 14064 providing the third-party verification structure that the GHG Protocol relies on in practice. The 2025 partnership formalizes what has been an informal alignment for over two decades.

The GHG Protocol and ISO are working toward final revised versions of the Corporate Standard, Scope 2 Guidance, and Scope 3 Standard by 2027. Harmonized ISO–GHG Protocol standards will follow. The exact nature of the changes is still being determined through public consultation. Companies shouldn’t panic, but they should stay informed, particularly regarding any methodology changes that could affect historical comparability or require recalculation of emissions baselines used for target-setting.

Scope 3 updates are part of the ongoing revision process, but the specifics are not yet finalized. What we do know is that Scope 3 reporting is increasingly weighted across major disclosure frameworks, and the harmonization effort is designed to make it more consistent and verifiable — not less rigorous. Companies with mature Scope 3 programs should monitor the public consultation process; companies just starting their Scope 3 journey should build their program on current GHG Protocol guidance while staying attentive to what changes.

One of the key benefits of harmonizing the two frameworks is a clearer, more consistent path to independent verification. Today, companies seeking assurance for their GHG inventories must navigate the interplay between GHG Protocol methodology and ISO 14064 verification requirements. Greater alignment between the two reduces ambiguity for both companies and assurance providers, ultimately strengthening the credibility of verified emissions data.

Our carbon accounting team tracks standards development across the GHG Protocol, ISO, and major reporting frameworks so our clients don’t have to. Whether you’re building a new GHG inventory, preparing for third-party verification, or assessing how the 2027 revisions might affect your existing program, we provide the expert guidance to keep your carbon accounting methods compliant, defensible, and audit-ready, through every update.

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