Governance & Policy
Sustainability Assurance
Definition
Sustainability assurance is the independent examination of reported sustainability information — emissions, ESG metrics, sustainability statements — by a qualified practitioner, giving users confidence in its reliability. Two levels exist: limited assurance (plausibility checks, "nothing has come to our attention") and reasonable assurance (audit-level evidence, positive opinion). Standards include ISAE 3000 and the dedicated ISSA 5000 issued by the IAASB in 2024; the CSRD mandates limited assurance initially, with a pathway to reasonable assurance.
References
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This reference provides supporting context for how “Sustainability Assurance” is defined and used.
Overview
How it is used
The practice structures verification of GHG inventories, CSRD and ISSB compliance, green bond post-issuance review, and audit committee oversight of ESG data.
Why it matters
Sustainability assurance is the audit profession arriving at the sustainability statement — the moment reporting becomes accountable.