Sustainability Assurance

Sustainability assurance is the independent verification, by a qualified assurance practitioner, of the non-financial information disclosed in an organisation's sustainability report. Under the EU CSRD Directive, all in-scope companies are required to obtain independent assurance at the "limited assurance" level from financial year 2024 onwards, which has firmly placed sustainability assurance on the agenda of large companies. In Türkiye, a similar obligation applies to entities subject to the Public Oversight Authority (KGK) under TSRS (Turkish Sustainability Reporting Standards).

Assurance Levels

CSRD requires limited assurance in the first phase, with a transition to reasonable assurance planned in later years.

Standards and Frameworks

• ISAE 3000 (Revised): The international baseline standard for assurance engagements on sustainability information.
• ISAE 3410: The assurance standard tailored to greenhouse gas statements.
• ISO 14064-3: The verification standard for carbon reporting.
• AA1000AS: AccountAbility's assurance standard, with a double materiality perspective.
• Turkish Assurance Standards (GDS): The TSRS verification framework issued by the KGK.

Stages of the Assurance Process

• Pre-planning and risk assessment: Materiality analysis of the report and identification of high-risk areas.
• Engagement letter: Documenting the scope and level of the engagement in writing.
• Internal control review: Evaluation of data collection and reporting processes.
• On-site assurance: Sample-based site visits and verification of data sources.
• Evidence review: Traceability analysis at the level of individual data points.
• Materiality assessment review: Applying the double materiality perspective in the field.
• Management representations: Obtaining statements of management responsibility.
• Drafting the assurance report: A limited or reasonable assurance report in ISAE 3000 format.
• Integration into the sustainability report: Including the assurance report within the published report.

Which Reports Are Assured?

• Sustainability reports prepared under GRI Standards 2021
• ESRS-compliant reports within the scope of CSRD
• TSRS 1 and TSRS 2 compliant reports in Türkiye
• CDP Climate Change, Water Security and Forests responses
• Carbon inventories under ISO 14064-1
• UN Global Compact CoP reports
• Integrated Reports (IIRC framework)

TÜRKAK Accreditation

Organisations providing sustainability assurance services are expected to have their independence and technical competence confirmed through TÜRKAK accreditation. ISO 14065 accreditation (for greenhouse gas validation and verification bodies) is a de facto requirement for carbon reports.

Sustainability assurance is about verifying the data behind the report, not writing the report. Good reporting is the final step of good data management; it is not possible to assure a report built on poor data.

Frequently Asked Questions

1. Is sustainability assurance different from a financial audit?

   Yes. A financial audit checks compliance with accounting standards, whereas sustainability assurance checks the accuracy of non-financial KPIs (emissions, water, social indicators, etc.). The methodology is similar, but the data sources and standards differ.

2. How long does an engagement take?

   Limited assurance: 6-10 weeks; reasonable assurance: 12-20 weeks. The number of sites and the maturity of the data have a direct impact on these timelines.

3. Can the same firm provide both consulting and assurance?

   No. Under the principle of independence, the same assurance team cannot both advise on the preparation of a report and verify that report. Separate organisational units or separate firms are appointed.

4. What is the cost of assurance?

   Between TRY 150,000-500,000 for limited assurance and TRY 350,000-1,000,000 for reasonable assurance, varying with the number of sites and the scope of the data. Costs are higher in the first year of CSRD and decrease by 30-50% in subsequent years.