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ISSB Standards in Australia: What IFRS S1 and S2 Mean for Local Businesses

ISSB Standards in Australia: What IFRS S1 and S2 Mean for Local Businesses

The International Sustainability Standards Board (ISSB) has fundamentally reshaped global sustainability reporting. In 2023, the ISSB published IFRS S1 and IFRS S2—international standards designed to create consistent, comparable sustainability disclosures worldwide. For Australian organisations, this matters because the Australian Accounting Standards Board has adopted these as AASB S1 and AASB S2, making ISSB standards the foundation of mandatory Australian sustainability reporting.

Understanding the connection between ISSB, IFRS, and Australia’s adoption process is essential for sustainability reporting compliance in Australia. This guide explains the ISSB framework, its standards, and what they mean for your organisation.

For a complete ESG strategy overview, see our complete ESG guide for Australian businesses.

What Is the International Sustainability Standards Board?

The ISSB is an independent, standard-setting board operating under the International Financial Reporting Standards (IFRS) Foundation. Established in 2021 and operationalised in 2022, the ISSB’s mandate is to develop sustainability-related financial disclosure standards that help investors, creditors, and other stakeholders assess risks and opportunities arising from sustainability-related matters.

The ISSB’s governance structure mirrors that of the IASB (International Accounting Standards Board), ensuring institutional credibility and global recognition. The board comprises members with expertise in sustainability, accounting, capital markets, and regional perspectives from across the world.

IFRS S1: General Requirements for Disclosure of Sustainability-related Financial Information

Core Purpose and Scope

IFRS S1 sets out general requirements for disclosing sustainability-related financial information. It applies to all entities and establishes a “sustainability-related financial information” framework—information about how an entity’s exposure to sustainability-related risks and opportunities affects its financial performance, position, and prospects.

IFRS S1 follows the “double materiality” concept, requiring entities to disclose information that is material from both a financial perspective (impact on financial outcomes) and from an impact perspective (how the entity affects people and the environment).

Four Pillar Structure

IFRS S1 organises disclosure requirements into four pillars:

  • Governance: How an entity’s governance addresses sustainability-related risks and opportunities
  • Strategy: How sustainability-related risks and opportunities affect the entity’s strategy and decision-making
  • Risk Management: How the entity identifies, assesses, and manages sustainability-related risks
  • Metrics and Targets: The metrics and targets used to assess and manage sustainability-related risks and opportunities

Governance Disclosure Under IFRS S1

IFRS S1 requires entities to disclose information about governance structures and processes, including:

  • Board composition and expertise in sustainability matters
  • Board committees responsible for sustainability oversight
  • Management structures and accountability for sustainability matters
  • Incentive structures and remuneration linked to sustainability performance
  • How governance processes inform strategy and risk management

Strategy and Business Integration

A key requirement of IFRS S1 is disclosure of how sustainability-related risks and opportunities are integrated into business strategy. Entities must explain:

  • How the business model incorporates sustainability considerations
  • How sustainability factors influence competitive positioning and market access
  • Transition strategies in response to sustainability-related shifts (for example, decarbonisation)
  • How strategy affects financial position and prospects

Risk Management Framework

IFRS S1 requires disclosure of how sustainability-related risks are identified, assessed, and managed within the entity’s risk management framework. This includes integration with financial risk management, board reporting on material risks, and mitigation strategies.

IFRS S2: Climate-related Disclosures

Focus and Scope

IFRS S2 is a sector-agnostic climate-specific standard that applies IFRS S1’s framework to climate-related risks and opportunities. It requires disclosure of information about how climate change affects an entity’s financial performance, position, and prospects.

IFRS S2 is aligned with the Task Force on Climate-related Financial Disclosures (TCFD) framework, ensuring consistency with established climate disclosure practice.

Governance and Oversight

IFRS S2 requires detailed disclosure of governance arrangements for climate matters, including:

  • Board oversight and relevant expertise
  • Management roles and responsibilities
  • Reporting structures and accountability
  • Governance processes for assessing and managing climate risks

Strategy Under Different Climate Scenarios

A distinguishing feature of IFRS S2 is the requirement for entities to disclose climate scenario analysis. Entities must explain how their strategy and business model would be affected under different climate scenarios, including scenarios that limit warming to 1.5°C and 2°C, as well as non-transition scenarios.

This includes disclosure of:

  • Transition risks (policy, legal, technology, market changes)
  • Physical risks (acute and chronic climate impacts)
  • Adaptation and resilience measures
  • Capital allocation and investment decisions

Greenhouse Gas Emissions Disclosure

IFRS S2 requires mandatory disclosure of Scope 1 and Scope 2 greenhouse gas emissions, with Scope 3 disclosure required where material. Key metrics include:

  • Absolute emissions (tCO₂e) for Scope 1 and Scope 2
  • Intensity metrics (emissions per unit of activity)
  • Progress towards targets and interim milestones
  • Methodology and assumptions used in quantification

Targets and Commitments

Where an entity has made climate-related commitments or targets, IFRS S2 requires disclosure of:

  • Target specifications (what is targeted, timeframe)
  • Baseline year and methodology
  • Progress measurement and reporting
  • Governance and accountability for achievement
  • Interim milestones or trajectory

How ISSB Standards Became Australia’s AASB S1 and S2

The Adoption Process

The Australian Accounting Standards Board adopted IFRS S1 and IFRS S2 substantially as written, with minimal modifications to align with Australian legislation and regulatory requirements. This adoption process involved:

  • Consultation by Treasury on the proposed mandatory reporting framework (2023–2024)
  • Amendments to the Corporations Act 2001 (Cth) to enable mandatory sustainability disclosure
  • AASB development of application guidance specific to Australian circumstances
  • Coordination with ASIC on enforcement and assurance requirements

Key Differences Between IFRS and AASB Standards

While AASB S1 and S2 are substantially based on IFRS S1 and S2, there are minor differences reflecting Australian regulatory requirements:

  • Consolidation basis: AASB standards use consolidated entity testing for determining which entities must comply
  • Assurance requirements: AASB S1 mandates limited assurance against APES 3000, reflecting Australian professional standards
  • Regulatory oversight: ASIC has enforcement authority and issues guidance through Regulatory Guides
  • Reporting timelines: Australia has a phased rollout for Groups 1, 2, and 3 entities

Timing of Implementation

Australia’s phased adoption timeline provides entities with structured compliance periods:

  • Group 1 (FY2025–26): Large entities including ASX-listed companies, first reports due 2026
  • Group 2 (FY2026–27): Medium entities, first reports due 2027
  • Group 3 (FY2027–28): Smaller entities, first reports due 2028

Global Adoption and Comparative Landscape

ISSB Adoption by Jurisdiction

The ISSB standards are being adopted or incorporated into national frameworks across major economies, including the European Union (through CSRD and ESRS), the United Kingdom, Canada, and increasingly in Asia-Pacific. This creates a global convergence toward consistent sustainability disclosure standards.

For multinational Australian organisations, adopting AASB S1 and S2 positions them to meet sustainability disclosure requirements in most key markets.

Interaction with GRI, TCFD, and Other Frameworks

ISSB standards don’t replace frameworks such as GRI or CDP—rather, they create a baseline of financial materiality requirements. Many organisations will continue to report against multiple frameworks to meet diverse stakeholder expectations. However, ISSB standards provide a unified disclosure structure that can be enhanced with voluntary metrics from other frameworks.

Practical Implementation: What Australian Businesses Must Do

Step 1: Materiality Assessment

Begin by conducting a double materiality assessment using AASB S1 definitions. This requires identifying both financial materiality (impact on financial performance) and impact materiality (entity’s impact on people and environment).

Step 2: Governance Structure Review

Assess current governance structures against AASB S1 requirements. This may require board committee restructuring, management role clarification, and documentation of sustainability oversight processes.

Step 3: Data Systems and Controls

Implement or enhance data management systems to capture sustainability metrics, particularly greenhouse gas emissions for AASB S2 compliance. Ensure internal controls are in place to support assurance requirements.

Step 4: Assurance Provider Engagement

Identify and engage an external assurance provider qualified to provide limited assurance under APES 3000. Early engagement allows the assurance provider to advise on data quality and reporting structures.

Step 5: Reporting Structure Development

Decide whether to issue a standalone sustainability report or integrate sustainability disclosures into the annual report and financial statements. Ensure clear cross-referencing between sustainability information and financial data.

Benefits and Challenges of ISSB Adoption in Australia

Benefits

  • Global comparability: AASB S1 and S2 alignment with ISSB standards enables comparison with international peers
  • Investor confidence: Standardised, assured sustainability information increases investor confidence and access to capital
  • Operational integration: Systematic sustainability governance improves operational resilience and risk management
  • Supply chain alignment: Suppliers and partners can provide consistent data to meet reporting requirements

Challenges

  • Data quality: Many organisations lack robust systems for collecting and verifying sustainability data
  • Expertise gaps: Sustainability reporting expertise may be limited in finance and governance teams
  • Scope 3 complexity: Particularly for organisations with complex supply chains, Scope 3 emissions measurement is challenging
  • Cost of implementation: Systems investment, external assurance, and expertise development require significant investment

Frequently Asked Questions

How do IFRS S1 and AASB S1 differ?

AASB S1 is substantially based on IFRS S1 but includes minor modifications to align with Australian legislation (Corporations Act), regulatory authority (ASIC), and assurance standards (APES 3000). The substantive requirements are the same.

Will ISSB standards continue to evolve?

Yes. The ISSB has identified potential future projects in areas such as natural capital, human capital, and sector-specific guidance. Organisations should monitor ISSB and AASB publications for updates.

Can organisations report under IFRS S1/S2 instead of AASB S1/S2?

For Australian mandatory reporting purposes, AASB S1 and S2 are the required standards. However, some large multinational organisations may choose to prepare IFRS S1/S2 reports for international stakeholders and reconcile with AASB requirements for Australian compliance.

How does ISSB address small entity concerns?

The ISSB has deliberately avoided a “small entity exemption,” as sustainability-related financial information is relevant to all entity sizes. Australia’s phased rollout (Groups 1, 2, 3) provides relief for smaller entities, deferring compliance dates.

What role do voluntary ISSB early adoptions play?

Some organisations adopt ISSB standards voluntarily before mandatory compliance dates. This is permitted and can provide competitive advantage and stakeholder confidence. Early adoption helps identify system gaps and governance enhancements needed for future mandatory compliance.

How are ISSB standards expected to evolve regarding emerging issues like nature and human capital?

The ISSB has indicated intention to develop standards on nature-related and human capital matters in future phases. Organisations should prepare governance frameworks flexible enough to accommodate future sustainability disclosure requirements.

Moving Forward with ISSB Adoption in Australia

Understanding the ISSB–IFRS–AASB connection is critical for compliance and effective implementation. The standards represent a significant shift toward investor-focused, financially material sustainability disclosure. Australian organisations adopting AASB S1 and S2 are not just meeting regulatory requirements—they’re positioning themselves within a global framework that enhances capital access, operational resilience, and stakeholder trust.

Ready to align your organisation with ISSB standards? Book a Free ESG Strategy Session to assess your current position relative to AASB S1 and S2 requirements.