GHG Protocol vs ISO 14064-1: which standard to choose in 2026

Quantifying and reporting greenhouse gas (GHG) emissions has become a strategic obligation for companies in Spain and across the EU. The two most widely used international references for doing so are the GHG Protocol and the ISO 14064-1 standard. In short: the GHG Protocol is the most widespread framework for communicating and comparing emissions globally, while ISO 14064-1 is a standard built for third-party verification, better suited to audits and to regulatory compliance in Spain. They are not mutually exclusive and, in fact, are often combined.

Between the requirements of Spain's MITECO carbon-footprint registry, the Corporate Sustainability Reporting Directive (CSRD), and pressure from investors and clients, the credibility and comparability of emissions data have become decisive. Below we break down both frameworks and how to decide which one best fits your strategy.

What is the GHG Protocol?

The GHG Protocol (Greenhouse Gas Protocol) is the international reference framework for greenhouse gas accounting. It was launched in 2001 by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD) with a clear goal: to provide a standard methodology that lets companies and sectors compare data on a like-for-like basis.

Its structure is organised around three scopes. Scope 1 covers the direct emissions a company controls, such as combustion in boilers or owned fleets. Scope 2 captures the indirect emissions associated with purchased energy (electricity, heat or steam). And Scope 3, the most complex and increasingly relevant, takes in the rest of the value-chain indirect emissions, from business travel to the transport of goods and purchased goods and services.

The reference corporate standard, the GHG Protocol Corporate Standard, was published in 2004 and last revised in 2015. It is worth knowing that the GHG Protocol is currently under revision: the draft of the updated corporate standard is expected to go out for public consultation in 2026, and the new edition is not anticipated until around 2027, so as of 2026 the current version remains in force.

What is the ISO 14064-1 standard?

ISO 14064-1:2018 is a standard from the International Organization for Standardization (ISO) that sets out the principles and requirements for quantifying and reporting GHG emissions and removals at organisation level. Unlike the GHG Protocol, which on its own does not include a certification mechanism, ISO 14064-1 is designed to be verifiable and auditable by accredited third parties.

The 2018 revision introduced an important change: instead of three scopes, the standard classifies emissions into six categories (direct emissions; indirect emissions from imported energy; emissions from transport; emissions from products used by the organisation; emissions associated with the use of the organisation's products; and other indirect emissions). In practice, these categories are compatible with the logic of scopes 1, 2 and 3, but they provide a more detailed breakdown designed for verification.

This standard is part of the ISO 14000 family of environmental management standards and integrates easily with systems such as ISO 14001. In Spain it carries added value: verification of ISO 14064-1 reports by bodies accredited by the Spanish National Accreditation Body (ENAC) meets the requirements of Spain's MITECO carbon-footprint registry for access to the verified seal.

Key differences between the GHG Protocol and ISO 14064-1

Although both pursue the same objective, accounting for and reporting GHG emissions, their approaches differ in origin, structure, verification and cost. This table summarises the key differences:

The GHG Protocol comes from a private initiative and is geared towards global comparability and communication with the markets. ISO 14064-1 comes from a formal standards body, which gives it a more auditable character. The clearest difference lies in verification: the GHG Protocol does not require it (although many companies undergo it voluntarily), whereas ISO 14064-1 contemplates accredited verification of the inventory from the outset, reinforcing the confidence of regulators, investors and clients.

Which standard suits you best, GHG Protocol or ISO 14064-1?

The answer depends on the organisation's main objective. If you are after global recognition and alignment with the major international frameworks, the GHG Protocol is the best foundation. It is closely tied to initiatives such as the Carbon Disclosure Project (CDP), the GRI Standards and science-based targets (SBTi), which all take the GHG Protocol as their methodological reference.

If what you need is regulatory backing, data traceability and the ability to pass official audits, ISO 14064-1 is the more appropriate choice. In Spain, its verification offers an advantage in public tenders and in contracts with large clients that demand verified evidence.

In many cases the most robust solution is to combine both approaches in a hybrid strategy: use the GHG Protocol for calculation, communication and international comparability, and ISO 14064-1 to guarantee compliance and credibility before public authorities and auditors. It is worth remembering that both frameworks are compatible, since they share the principles of relevance, completeness, consistency, transparency and accuracy.

Frequently asked questions about the GHG Protocol and ISO 14064-1

Does the MITECO registry accept both standards?

Yes. Spain's MITECO carbon-footprint registry accepts inventories calculated with the GHG Protocol or with ISO 14064-1. To access the verified seal, verification by an accredited body is required, something ISO 14064-1 integrates naturally.

Which of the two standards is more expensive to apply?

The GHG Protocol is usually cheaper because it does not require certification. ISO 14064-1 involves additional audit and external verification costs, but it brings greater credibility with third parties.

Can both standards be applied at the same time?

Yes. More and more companies use the GHG Protocol for calculation and international communication and ISO 14064-1 to meet regulatory requirements in Spain and the EU. Their methodologies are compatible.

Does ISO 14064-1 still use scopes 1, 2 and 3?

The 2018 version reorganises emissions into six categories, but it also allows reporting according to scopes 1, 2 and 3 of the GHG Protocol, with which it is consistent.

If you want to dig deeper into the Spanish registry's requirements, we recommend our guide to the MITECO registry and the Calculate, Reduce and Offset seals. And if you need to implement and verify your inventory under ISO 14064-1, explore Manglai's ISO 14064 solution.