A Simple Guide to ESRS and ISSB Sustainability Standards

Breaking Down ESRS and ISSB Standards Shaping the Future of Sustainability Reporting

Juliette Camou
December 3, 2025
Sustainable Regulations

Sustainability reporting has become an essential focus for companies worldwide as investors, customers, and regulators increasingly demand transparency about how businesses impact the environment and society. To meet these growing expectations, various regulations and reporting frameworks have been developed to guide companies in disclosing relevant sustainability information. Among the most significant standards today are the European Sustainability Reporting Standards (ESRS), the International Sustainability Standards Board (ISSB) standards, and the U.S. Securities and Exchange Commission (SEC) Climate Disclosure Rule. This article provides a clear overview of these three frameworks, explaining what they are, how they differ, and where sustainability reporting is headed.

What Is ESRS?

The European Sustainability Reporting Standards (ESRS) are a set of regulations developed by the European Union to help companies provide clear, comparable, and consistent sustainability information. These standards are designed to ensure that companies disclose material information related to their environmental, social, and governance (ESG) impacts in accordance with the EU’s evolving climate and sustainability policies.

ESRS covers a broad range of topics, including climate change, environmental performance, social and labor impacts, governance, and ethics. One of the key objectives of ESRS is to facilitate transparency and comparability across companies operating in the European markets by setting general requirements and specific disclosure requirements. The ESRS standards include two cross-cutting standards and ten topical standards, ensuring comprehensive coverage of sustainability issues. This includes the principle of double materiality, which means companies must report not only on how sustainability issues affect their financial position but also on their own impacts on the environment and society. Companies must conduct a double materiality assessment to identify material sustainability topics relevant to their operations.

Moreover, ESRS has been developed with inclusivity in mind, providing guidance tailored to small and medium-sized enterprises (SMEs) to make sustainability reporting more accessible. The standards require companies to provide general disclosures about their governance and management of sustainability risks and opportunities, as well as detailed information about their activities, policies, and performance related to climate change and social matters. ESRS 1 General requirements cover important concepts and principles which must be followed when reporting under the CSRD, ensuring consistency and clarity in disclosures. The obligation to report on the topical standards depends on the results of the company's double materiality assessment.

By complying with ESRS, companies operating in the EU meet mandatory obligations designed to deliver decision-useful information to investors and other stakeholders, helping them assess risks and opportunities related to sustainability. The standards also support companies in aligning with the European Sustainability Reporting Directive (CSRD), which sets the force and condition for these reporting requirements.

What Is ISSB?

The International Sustainability Standards Board (ISSB), established by the IFRS Foundation, is developing global sustainability standards aimed at integrating sustainability information directly into companies’ financial reporting. The ISSB was formed on 3 November 2021 at COP26 in Glasgow, marking a significant step toward creating a unified approach to sustainability reporting. Unlike ESRS, which has a broader ESG focus, ISSB standards emphasize financially material sustainability information that affects a company’s financial risks, opportunities, and long-term value creation.

ISSB standards focus on climate-related risks, social issues, governance practices, and sustainability opportunities that are relevant to investors and financial markets worldwide. The board’s work is centered on creating one global baseline for sustainability disclosure, enabling companies across regions to provide consistent, comparable, and decision-useful information in accordance with international rules.

The standards developed by ISSB include general disclosures and subject-specific requirements that help companies report on sustainability topics that materially impact their financial condition and performance. This approach supports investors in making informed decisions by providing data on how sustainability factors influence a company’s risk profile and strategic management. The ISSB has issued the first two IFRS Sustainability Disclosure Standards, which include a general standard and a climate standard, setting a foundation for consistent global reporting. The ISSB is developing standards that will result in a high-quality, comprehensive global baseline of sustainability disclosures.

While ISSB standards are currently voluntary, they are rapidly gaining traction as markets and regulators recognize the need for harmonized sustainability reporting to reduce complexity and improve efficiency. The ISSB’s work complements existing frameworks by focusing on the financial implications of sustainability and aligning with international financial reporting standards. The ISSB has international support for its work to develop sustainability disclosure standards from various global organizations.

How These Three Standards Compare

When comparing ESRS, ISSB, and the SEC Climate Disclosure Rule, several key differences and similarities emerge in terms of scope, focus, and regulatory status.

Scope & Focus

  • ESRS: Focuses broadly on ESG topics, covering environmental, social, and governance impacts. It mainly applies to companies operating within the European Union and emphasizes double materiality.
  • ISSB: Concentrates on financially material sustainability information relevant to investors globally. It aims to create a unified global baseline for sustainability reporting connected to financial statements.

Mandatory vs. Voluntary

  • ESRS: Mandatory for many companies under the EU’s Corporate Sustainability Reporting Directive (CSRD).
  • ISSB: Currently voluntary but increasingly adopted worldwide by companies seeking alignment with global markets and investor expectations.

Reporting Style

  • ESRS: Requires detailed ESG indicators and disclosures, including general disclosures and specific disclosure requirements.
  • ISSB: Emphasizes sustainability information that is financially material, linking sustainability data with financial reporting.

How Companies Can Prepare

To comply with these evolving regulations and standards, companies need to establish robust processes for sustainability data collection, management, and reporting. This involves setting up reliable systems to track relevant data, reviewing climate and social risks and opportunities, and fostering collaboration across departments such as finance, legal, and sustainability teams.

Accurate and consistent reporting requires companies to control the quality of their sustainability information, ensuring it meets the general requirements and specific disclosure obligations set by these standards. By doing so, companies not only comply with mandatory rules but also provide decision-useful information that meets the needs of investors and other stakeholders.

In addition to regulatory compliance, following these frameworks can improve transparency, build trust, and support better long-term planning. Enhanced sustainability reporting helps companies identify risks and opportunities related to climate change and social impacts, enabling more efficient management and strategic resilience. Furthermore, meeting these standards can unlock market opportunities by demonstrating a company’s commitment to responsible business practices and sustainability leadership.

Where Sustainability Reporting Is Headed

Sustainability reporting standards continue to evolve rapidly, shaped by several key trends that will influence future regulations and corporate disclosures.

One major trend is the increasing alignment between different frameworks like ESRS, ISSB, and SEC rules to reduce complexity and duplication for companies operating in multiple regions. This harmonization aims to provide clearer guidance and more efficient reporting processes. The ESRS will include sector-specific standards that are under development, with draft sector standards expected for the first 8-10 sectors during 2024, further enhancing the granularity and relevance of sustainability disclosures. A digital approach to CSRD reporting is a must, as the CSRD sustainability statement cannot be done manually.

There is also a growing emphasis on forward-looking analysis, with companies expected to provide scenario-based disclosures that assess how future climate change and social developments might impact their business. Technology, including artificial intelligence and digital reporting tools, is playing a larger role in improving data accuracy, efficiency, and transparency.

Furthermore, sustainability reporting is moving beyond voluntary disclosures toward mandatory obligations in many jurisdictions, reflecting the growing importance of sustainability in mainstream financial and corporate governance. This shift highlights the need for companies to integrate sustainability into their core management and risk frameworks.

Ultimately, these standards aim to deliver decision-useful information that reflects companies’ environmental and social impacts, risks, and opportunities. By following regulations like ESRS, ISSB, and the SEC Climate Disclosure Rule, companies can better meet stakeholder expectations, improve governance, and enhance their ability to adapt to a rapidly changing climate and social landscape.

Implementing Sustainability Regulations: Key Considerations

Implementing sustainability regulations like ESRS, ISSB standards, and the SEC Climate Disclosure Rule requires companies to establish robust governance and management systems. Governments (gov) and regulatory bodies provide detailed guidance and publications to support companies in meeting their obligations. For example, the EU regularly updates ESRS-related guidance, with important publications and notes often released in December to coincide with reporting cycles.

Companies must engage individuals across departments, from sustainability teams to finance and legal, to ensure comprehensive data collection and compliance. It is crucial to check for updates regularly and stay informed about evolving rules to maintain compliance and leverage opportunities.

The Role of Stakeholders and Individual Rights in Reporting

Sustainability reporting is not only about corporate obligations but also about respecting the rights and interests of individuals and stakeholders affected by company activities. Stakeholder engagement is a key part of the double materiality assessment process, helping companies identify material topics that matter most to people and the environment.

Companies should provide transparent disclosures that allow investors, customers, and the public to read and understand their sustainability performance. This openness builds trust and supports better decision-making by all parties involved.

Digital Tools for Efficient Reporting and Compliance

Given the complexity and volume of data involved, implementing digital solutions is essential for efficient sustainability reporting. Software platforms help companies manage data collection, perform double materiality assessments, and prepare disclosures in accordance with regulations.

For instance, tools like Aclymate provide end-to-end climate software solutions tailored for small and mid-sized businesses, helping them measure, reduce, and report their environmental impacts with confidence. Using such technology ensures accuracy, supports compliance with mandatory rules, and streamlines the publication process.

Recent Updates and Future Outlook

Regulations in sustainability reporting continue to evolve rapidly. Companies should note recent updates from regulatory bodies, including those published in December, which often include clarifications or new requirements.

The UK (uk) government and other jurisdictions are also developing or updating their sustainability frameworks, reflecting growing global alignment in reporting standards. Staying informed and proactive is essential for companies to comply and remain competitive.

For more detailed guidance, read official publications from regulatory authorities and check for updates regularly to ensure your reporting aligns with the latest regulations.

If your company is looking for an all-in-one solution to navigate these complex sustainability reporting requirements, Aclymate offers comprehensive climate software and expert consulting tailored to small and mid-sized businesses. From carbon accounting and reporting to verified offsets and certifications, Aclymate helps you measure, reduce, and disclose your environmental impact with confidence. Visit Aclymate to learn more and get started on your sustainability journey today.

FAQs

1. What are the European Sustainability Reporting Standards (ESRS)?
ESRS are mandatory disclosure standards developed by the European Union to help companies provide transparent, comparable, and consistent sustainability information covering environmental, social, and governance (ESG) impacts. They emphasize the principle of double materiality and apply mainly to companies operating within the EU.

2. How does the International Sustainability Standards Board (ISSB) differ from ESRS?
The ISSB focuses on creating a global baseline for sustainability disclosures that are financially material to investors, integrating sustainability information into financial reporting. In contrast, ESRS covers a broader ESG scope with mandatory requirements primarily in the European market.

3. What is double materiality in sustainability reporting?
Double materiality means companies must report not only how sustainability issues impact their financial position but also how their operations affect the environment and society. It involves assessing sustainability from both an inside-out and outside-in perspective.

4. How can companies prepare for these sustainability reporting requirements?
Companies should establish robust governance, data collection, and management systems; conduct double materiality assessments; stay updated on regulatory changes; and consider digital tools to streamline reporting and ensure compliance.

5. Will sustainability reporting frameworks become more aligned in the future?
Yes, there is a growing trend toward harmonization among ESRS and ISSB rules, and other frameworks to reduce complexity and duplication, making it easier for companies to comply across different regions.

Juliette Camou
December 3, 2025

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