Carbon Footprint Verification and Certification

Carbon footprint verification and certification are the stages that confirm, through independent review, that an organisation's greenhouse gas (GHG) emissions calculation is correct, complete and reliable. They bring credibility, transparency and accuracy to reported information — something essential for building trust with stakeholders and meeting regulatory requirements.

Why verifying the carbon footprint matters

Ensures data quality

The accuracy of the calculation depends on the quality of the data. Verification detects errors, omissions and inconsistencies, and confirms that the carbon footprint reflects the reality of emissions.

Builds trust

A report verified by an independent third party provides greater assurance to investors, customers, regulators and the public. It demonstrates a commitment to transparency and accountability.

Helps meet regulatory requirements

A growing number of frameworks require sustainability information to undergo assurance. The CSRD, for example, requires the published information under the ESRS to be verified, starting from a limited assurance level. In Spain, registering the footprint in the MITECO carbon footprint register also requires rigorous documentation.

Identifies improvement opportunities

The process reveals where to strengthen data management, calculation and reduction measures.

Stages of verification

1. Internal review

Before external verification, it is advisable to internally review the data, methodologies, calculations and narrative of the emissions inventory to correct any errors.

2. Selection of the verifier

It must be an independent and accredited body (in Spain, accredited by the National Accreditation Entity, ENAC). Independence from the company guarantees impartiality.

3. Verification process

This is a retrospective review in which the verifier assesses the methodology, checks the activity data and emission factors applied, and evaluates the integrity of the report. Additional information may be requested.

4. Assurance report

The final deliverable is a statement or report expressing the level of confidence in the results. Here, the distinction between the two assurance levels is key:

• Limited assurance: the verifier concludes that no elements have been found that would lead them to believe the information is incorrect. It requires less depth and fewer resources.
• Reasonable assurance: it provides a stronger guarantee and a positive opinion on the information, but requires more work and better internal preparation.

Standards and methodologies

GHG Protocol

The GHG Protocol is the most widely used international standard for preparing the GHG inventory and classifying emissions by scope.

ISO 14064

ISO 14064 is organised in three parts: part 1 covers quantification and reporting at the organisational level; part 2 covers emission reduction projects; and part 3 (ISO 14064-3) sets out the requirements for the validation and verification of GHG statements. The ISAE 3000 standard is also used for the assurance of sustainability information.

Good practices

• Early planning: define objectives, scope, resources and timeline.
• Thorough documentation: retain data, methodologies, calculations and assumptions.
• Clear communication between the internal team and the verifier.
• Continuous improvement: implement the verifier's recommendations in the next cycle.

Verifying the carbon footprint turns an internal calculation into credible and comparable information, and typically goes hand in hand with a prior carbon audit. At Manglai we help companies measure their carbon footprint and prepare their sustainability information for verification. Discover how Manglai can help you.