Updated 21 September 2026: the ISSB’s nature-related requirements are in development, not final. This version reflects the current work-plan status.
Introduction: From Carbon to Nature
Nature and biodiversity are moving closer to the centre of investor-focused sustainability reporting. The shift is real, but it is important to describe it accurately: the ISSB has moved nature-related disclosures into standard-setting and is developing proposed requirements. In May 2026, the ISSB said it aimed to publish an exposure draft for public comment in October 2026; no final ISSB nature standard has yet been issued.
That developing agenda presents a difficult question for the assurance profession: how do we make complex, location-specific ecological information auditable without reducing nature to a single convenient number?
Calculative infrastructures and auditability
My ongoing PhD research considers the calculative infrastructures that support market integrity. As with the Australian Carbon Credit Unit scheme, the credibility of nature-related claims depends on the systems beneath the disclosure: definitions, boundaries, source data, estimation methods, controls, expert judgement and evidence trails.
Nature-related information adds challenges that carbon accounting does not fully capture. Dependencies and impacts vary by ecosystem and location. Baselines can change over time. The same activity can produce different consequences in different places. A reliable disclosure therefore needs more than a headline metric; it needs a transparent chain from observation and methodology to judgement and reported claim.
What assurance readiness should test
For preparers and assurance practitioners, five questions deserve early attention:
- Boundary: Which operations, value-chain relationships and locations are included, and why?
- Evidence: Can the organisation trace each material claim to identifiable data, controls and responsible owners?
- Method: Are estimates, proxies and scientific models documented well enough for another qualified person to understand and challenge them?
- Expertise: Where is ecological or other specialist judgement required, and how is that work evaluated within the assurance engagement?
- Connectivity: Do nature-related claims align with climate disclosures, strategy, risk management and financial reporting rather than sitting in a separate narrative?
Readiness or “pre-assurance” work can help organisations find these weaknesses before a formal engagement, but it should not be presented as assurance and must be designed with independence in mind.
A developing global infrastructure
The ISSB is drawing on existing market practice, including the Taskforce on Nature-related Financial Disclosures (TNFD) recommendations. At the same time, ISSA 5000 provides a topic-neutral global baseline for sustainability assurance engagements. Together, these developments point toward an infrastructure in which nature-related information will increasingly be expected to withstand disciplined testing.
The central challenge is not to make nature look simple. It is to make the assumptions, evidence and uncertainty visible enough that users can understand what a claim means — and assurance practitioners can test whether it is supportable.