Quick Answer — What is ISSB?

ISSB Overview and Structure

The ISSB was established in November 2021 as an independent board within the IFRS Foundation1. It builds on and consolidates the work of existing frameworks including the Task Force on Climate-related Financial Disclosures (TCFD), the Sustainability Accounting Standards Board (SASB), the Climate Disclosure Standards Board (CDSB), the Integrated Reporting Framework, and the CDP.

Key characteristics

  • Independent governance within IFRS Foundation structure
  • Global standard-setter for sustainability disclosure
  • Focus on enterprise value and investor decision-making
  • Single materiality approach (financial materiality)
  • Built on existing market-tested frameworks

The ISSB consolidated these frameworks into a coherent global baseline, avoiding duplication while maintaining the substance of widely-adopted frameworks like TCFD and SASB.

IFRS S1 and S2 Standards

The ISSB published IFRS S1 and IFRS S2 on 26 June 20232 as the foundation for global sustainability disclosure.

IFRS S1: General Requirements

  • Framework for disclosure of sustainability-related financial information
  • Four-pillar structure: governance, strategy, risk management, metrics and targets
  • Enterprise value materiality assessment
  • Cross-reference to topic-specific standards (starting with IFRS S2)
  • Annual reporting cycle aligned with financial statements

IFRS S2: Climate-related Disclosures

  • First topic-specific standard applying IFRS S1 framework
  • Built on TCFD recommendations with enhanced requirements
  • Mandatory GHG emissions disclosure (Scope 1, 2, and 3)
  • Scenario analysis and transition planning
  • Industry-based metrics from SASB Standards

IFRS S1 provides the general framework while IFRS S2 demonstrates how that framework applies to climate-related risks and opportunities specifically.

December 2025 Amendments to IFRS S2

In December 2025, the ISSB issued targeted amendments to IFRS S23 covering GHG emissions disclosures. These amendments provide reliefs and clarifications to reduce complexity and duplicative reporting, effective 1 January 2027 with early application permitted.

Key amendments include:

  • Financed emissions disaggregation relief for financial institutions
  • GHG Protocol jurisdictional relief where alternative methodologies required
  • IPCC Global Warming Potential relief for jurisdictions with different requirements
  • GICS classification relief allowing alternative sector classification systems

The December 2025 amendments also included consequential amendments to three SASB Standards (Asset Management, Commercial Banking, Insurance) to align financed emissions metrics3.

Global Adoption (40+ Jurisdictions)

According to the IFRS Foundation tracker, 40+ jurisdictions are adopting or using ISSB Standards4, representing approximately 60% of global market cap, 60% of global GDP, and 40%+ of global GHG emissions5.

Key adopting jurisdictions:

  • United Kingdom: UK SRS S1/S2 (with six amendments)
  • Australia: AASB S1/S2 (phased implementation by entity size)
  • Brazil: NBC TSC approved for voluntary use
  • Canada: CSDS 1 and CSDS 2 aligned with ISSB
  • Japan: SSBJ Standards permitted (FSA decision pending)
  • Singapore: Mandatory climate disclosure from 2025 (SGX RegCo)
  • Other jurisdictions: China, Nigeria, Mexico, Türkiye, Philippines, Qatar, Chile

The IFRS Foundation has published jurisdictional profiles for many adopting jurisdictions, providing detailed implementation approaches and local adaptations4.

ISSB and UK SRS Relationship

UK SRS S1 and S2 are the UK's endorsed versions of IFRS S1 and S2. The six UK amendments adapt the ISSB baseline for UK regulatory context while preserving the substance of the international standards.

How ISSB relates to UK SRS:

  • UK SRS S1/S2 are UK's endorsed versions of IFRS S1/S2
  • Six targeted UK amendments for UK market conditions
  • UK endorsement process required for each new/amended ISSB standard
  • Automatic adoption does NOT occur — each ISSB update requires UK consideration
  • FRC manages UK endorsement process with DBT policy leadership

ISSB Work Programme

The ISSB has ongoing projects that may result in additional sustainability disclosure standards beyond IFRS S1 and S2:

Current work programme includes:

  • Nature-related disclosures project (building on TNFD framework)
  • Human capital disclosures project
  • Biodiversity and ecosystem-related risks and opportunities
  • Integration with other reporting frameworks and taxonomies

Any new ISSB standards would require separate UK endorsement processes before becoming part of UK SRS. The UK maintains the ability to adapt ISSB standards for UK regulatory and market characteristics.

What is the ISSB?

The International Sustainability Standards Board (ISSB) is an independent standard-setting body within the IFRS Foundation, established in 2021. It issued IFRS S1 and S2 in June 2023, providing the global baseline for sustainability disclosure adopted in 40+ jurisdictions.

What are IFRS S1 and S2?

IFRS S1 provides general requirements for sustainability disclosure using a four-pillar framework. IFRS S2 applies this framework specifically to climate-related risks and opportunities, building on TCFD with enhanced requirements including mandatory Scope 1, 2, and 3 GHG emissions.

How many jurisdictions have adopted ISSB Standards?

40+ jurisdictions are adopting or using ISSB Standards, covering approximately 60% of global market cap, 60% of global GDP, and 40%+ of global GHG emissions. Key adopters include UK, Australia, Brazil, Canada, Japan, and Singapore.

How do UK SRS relate to ISSB Standards?

UK SRS S1 and S2 are the UK's endorsed versions of IFRS S1 and S2 with six UK-specific amendments. New ISSB standards do not automatically apply in the UK — each must go through UK endorsement before entering UK SRS.

What were the December 2025 ISSB amendments?

The ISSB issued targeted amendments to IFRS S2 in December 2025 covering GHG emissions disclosures, providing reliefs for financed emissions, GHG Protocol jurisdictional differences, and IPCC Global Warming Potential requirements. Effective 1 January 2027.

What other standards is the ISSB working on?

The ISSB work programme includes nature-related and human capital disclosure projects. However, any new ISSB standards would require separate UK endorsement processes before becoming part of UK SRS.