When will ISSB standards become mandatory in the UK?

The UK government has endorsed the ISSB standards and is developing UK Sustainability Disclosure Standards (UK SDS) based on IFRS S1 and S2. The timeline is still being finalised, but large listed companies should expect mandatory requirements from 2025 or 2026. Early preparation is recommended.

How does the ISSB relate to the TCFD?

The ISSB standards fully incorporate the TCFD recommendations. IFRS S2 is built on the TCFD framework (governance, strategy, risk management, metrics and targets) but goes further by adding specific mandatory disclosure requirements. The TCFD has been effectively superseded by the ISSB.

ISSB (International Sustainability Standards Board)

The ISSB is a standard-setting body under the IFRS Foundation that has developed global baseline sustainability disclosure standards (IFRS S1 and IFRS S2) for capital markets.

What is ISSB (International Sustainability Standards Board)?

The International Sustainability Standards Board (ISSB) was established in November 2021 at COP26 in Glasgow to create a comprehensive global baseline of sustainability disclosures for capital markets. It issued its first two standards in June 2023: IFRS S1 (General Requirements for Disclosure of Sustainability-related Financial Information) and IFRS S2 (Climate-related Disclosures).

IFRS S2 requires companies to disclose Scope 1, 2, and 3 greenhouse gas emissions, climate-related risks and opportunities, transition plans, and climate targets. The standards are designed to be interoperable with the CSRD/ESRS in Europe and jurisdiction-specific requirements globally.

The UK government has indicated it will adopt the ISSB standards as the basis for UK sustainability disclosure requirements, through the UK Sustainability Disclosure Standards (UK SDS). This means UK companies should prepare for ISSB-aligned reporting as a near-term regulatory requirement.

Practical Examples

A FTSE 250 company begins preparing for IFRS S2 compliance by enhancing its Scope 3 emissions measurement and documenting its climate-related risks and transition plan.

An international company aligns its sustainability reporting framework with IFRS S1 and S2 to meet investor expectations across multiple jurisdictions simultaneously.

The UK Financial Conduct Authority consults on requiring ISSB-aligned disclosures for listed companies, prompting early adoption across the London market.

How Climatise Helps

Climatise generates emissions data structured for ISSB/IFRS S2 reporting requirements, covering all three scopes with the methodological transparency and data quality needed for investor-grade disclosures.

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