ESG reporting standards compared: GRI, ISSB, ESRS and UK SRS

Key takeaways

• Frameworks, standards and regulations are related but different: frameworks guide, standards specify, and regulations require ESG disclosure.
• GRI focuses on an organisation’s impacts on people and the planet. ISSB, UK SRS and SASB look at sustainability risks and opportunities that impact financial performance. ESRS covers both through double materiality.
• UK listed companies will need to report against UK SRS on a comply-or-explain basis for financial years starting on or after 1st January 2027.
• After the EU Omnibus I reforms, the CSRD applies only to the largest groups, but UK companies with significant EU turnover can still be in scope from 2028.
• Most organisations use more than one of these ESG frameworks and standards, and the GHG Protocol underpins the carbon data in almost all of them.

What is an ESG reporting standard?

A sustainability reporting standard provides structure for how an organisation discloses ESG information, meaning its environmental, social and governance data. It sets out which topics matter, how to decide what is material and how to present the results, so investors, customers, regulators and other stakeholders can compare one company with another.

Without standardisation, sustainability reports tend to become selective, hard to verify and impossible to benchmark. With one, ESG data becomes useful for investment, lending and procurement decisions. That is why ESG reporting is now routine for large companies. KPMG’s 2024 survey of 5,800 companies across 58 countries found that the GRI Standards alone are used by 71% of the largest 100 companies in each country and 77% of the world’s 250 largest companies.

How ESG frameworks and standards organise disclosure

Most modern ESG frameworks and standards share an architecture inherited from the Task Force on Climate-related Financial Disclosures (TCFD).Disclosures are grouped into four pillars:

• Governance: who oversees sustainability-related risks and opportunities, and how.
• Strategy: how those risks and opportunities affect the business model, value chain and financial planning.
• Risk management: how risks are identified, assessed and built into wider risk processes.
• Metrics and targets: the data used to track performance, such as greenhouse gas emissions, waste and resource use, and progress against targets.

The standards differ most in materiality, the test that decides what makes the cut.

• Financial materiality asks how sustainability issues affect the company.
• Impact materiality asks how the company affects people and the environment.
• Double materiality, used by ESRS, asks both questions, and half of the world’s largest companies now say they apply it.

The environmental, social and governance (ESG) topics they cover

ESG topics fall into three groups:

• Environmental: climate change, pollution, water, biodiversity, and resource use and the circular economy.
• Social: the workforce, workers in the value chain, affected communities and consumers.
• Governance: business conduct, board oversight, anti-corruption and the link between executive pay and sustainability performance.

Resource use and waste are often underestimated. ESRS has a dedicated circular economy standard (ESRS E5), GRI has a waste standard (GRI 306), and waste generated in operations is a Scope 3 category under the GHG Protocol. Reliable waste and material data therefore inputs to ESG disclosure, not just an operational metric.

What is the difference between ESG frameworks, standards and regulations?

The three terms are often used interchangeably, but describe different instruments. Confusing them is one of the most common causes of over-reporting, under-reporting and wasted effort.

A framework sets out principles and a structure. TCFD and TNFD are frameworks: they tell you which areas to address but leave room for judgement on the detail.

A standard is more specific. It defines specific ESG disclosure requirements, metrics and calculation methods so that reports are consistent and can be assured. The GRI Standards, SASB Standards, IFRS S1 and S2, UK SRS and ESRS are all standards.

A regulation sets out what a company must legally report on, usually by referencing a standard. The CSRD requires ESRS reporting, while the FCA’s UK Listing Rules now reference UK SRS.

Disclosure platforms such as CDP collect data through annual questionnaires. ESG ratings providers score companies using their own methodologies, often drawing on published reports and CDP responses.

What are the main ESG reporting frameworks and standards?

The table below compares the main sustainability reporting frameworks and standards that UK and international companies are likely to encounter, including their purpose, audience and reporting status.

GHG Protocol, CDP and TNFD: the wider sustainability reporting toolkit

Alongside the core standards, three tools shape almost every ESG report: the GHG Protocol for carbon accounting, CDP for investor and customer disclosure, and TNFD for nature.

How does the GHG Protocol support sustainability reporting?

The GHG Protocol, developed by the World Resources Institute and the World Business Council for Sustainable Development, is the accounting rulebook for greenhouse gas emissions. It splits emissions into Scope 1 (direct), Scope 2 (purchased energy) and Scope 3 (the value chain, including purchased goods, transport and waste generated in operations).

The GHG Protocol does not tell companies what to disclose. Instead, it provides a consistent method for calculating greenhouse gas emissions that organisations can use in disclosures under IFRS S2, UK SRS S2, ESRS E1 and CDP. Its standards underpin much of corporate carbon accounting, including measurement of Scope 1, 2 and 3 emissions. The Protocol is being revised, so organisations that use renewable energy certificates should monitor updates to its guidance on market-based emissions reporting.

Scope 3 is where most companies struggle, because the data sits with suppliers and service providers. Waste is a good example: accurate tonnages, waste types and treatment routes from a digital waste tracking system make Scope 3 waste emissions far more defensible than spend-based estimates.

CDP, CSRD/ESRS and TNFD: other reporting approaches

CDP is a global disclosure system that collects environmental data through questionnaires on climate, water, forests, biodiversity and plastics. Its influence comes from who requests the data. In 2025, more than 22,100 companies representing over half of global market capitalisation disclosed through CDP, at the request of 640 investors with US\$127 trillion in assets. This same cycle saw more than 270 major buyers ask around 45,000 suppliers to disclose, which is why many mid-sized companies first meet ESG requirements through a customer request rather than a regulator.

The Taskforce on Nature-related Financial Disclosures (TNFD) extends the TCFD model to nature and biodiversity, as nature-related risks become part of mainstream investment analysis. Uptake has accelerated sharply: 1,154 organisations made TNFD-aligned disclosures in 2026, more than double the 542 recorded in 2025, and 802 have registered as formal adopters. The ISSB is now developing nature-related requirements that draw on the TNFD framework.

ESRS and the CSRD are covered in the next section, because their 2026 changes matter most for UK groups with EU operations.

Which ESG reporting standards matter in the UK in 2026?

For UK companies, three developments define the year: the publication of UK SRS, the FCA’s final rules for listed companies and the narrowing of the EU’s CSRD. Alongside these, existing requirements such as Streamlined Energy and Carbon Reporting (SECR) and the Companies Act climate-related financial disclosures still apply to large companies.

UK SRS standards overview

The UK Sustainability Reporting Standards (UK SRS) are the UK’s baseline for investor-focused sustainability disclosure. On 25th February 2026, the Department for Business and Trade published UK SRS S1 and UK SRS S2, alongside its response to the 2025 consultation. The standards are the UK-endorsed versions of the ISSB’s IFRS S1 and IFRS S2 and are available for any organisation to use voluntarily. They aim to give investors consistent, comparable information to support investment decisions in UK markets.

The two UK SRS standards work as a pair:

• UK SRS S1: General Requirements for Disclosure of Sustainability-related Financial Information. Sets the overall rules: which sustainability-related risks and opportunities to report, how to judge financial materiality, how to connect disclosures to the financial statements, and how to structure them around governance, strategy, risk management, and metrics and targets.
• UK SRS S2: Climate-related Disclosures. Applies those rules to climate. It covers physical and transition risks, climate resilience and scenario analysis, Scope 1, 2 and 3 greenhouse gas emissions, climate targets and industry-based metrics.

FCA UK SRS rules for listed companies

On 30th September 2026, the FCA published Policy Statement PS26/19, setting out its final UK Listing Rules. The FCA UK SRS rules replace TCFD-aligned requirements with rules for reporting against UK SRS, come into force on 1 January 2027 and apply to listed companies. The key points are:

• Comply or explain for everything. The FCA had proposed mandatory climate disclosures, but moved to comply or explain for all UK SRS disclosures after consultation feedback.
• Timing. The rules apply to financial years starting on or after 1 January 2027, so the first reports will be published in 2028.
• Phased reliefs. Companies get one year of relief for Scope 3 emissions and two years for wider UK SRS S1 disclosures.
• Transition plans. Listed companies must say whether they have published a transition plan and where, or explain why not.
• Assurance transparency. Companies that obtain assurance must name the provider, the level of assurance and the standard used.
• International issuers. Overseas companies with a secondary listing and depositary receipt issuers are also in scope.

Comply or explain should not be read as optional. The FCA has reminded issuers that if climate or other sustainability issues are among their principal risks, they still need to be reflected in their reporting.

Alongside the policy statement, the FCA published Primary Market Bulletin 66, which consults on a draft technical note (TN 803.1). The note explains how the UK SRS S1 statement of compliance works when a company chooses to explain rather than comply.

When might UK businesses need to consider CSRD and ESRS?

Leaving the EU did not take UK companies out of the CSRD. There are three main routes into scope:

1. An EU subsidiary that meets the thresholds. Any EU company with more than 1,000 employees and more than €450 million in net turnover must report under ESRS, even if its parent is in the UK. This applies to financial years starting in 2027, with reports due in 2028.
2. The non-EU parent rule. A UK parent needs to report under the CSRD if it generates more than €450 million in net turnover in the EU for each of the previous two consecutive financial years and has either a qualifying large EU subsidiary or an EU branch generating more than €200 million in net turnover. This applies to financial years starting on or after 1 January 2028, with reports due in 2029.
3. The value chain. Customers that report under the CSRD will ask suppliers for data. Suppliers with fewer than 1,000 employees can now decline requests that go beyond the voluntary standard for smaller companies.

The non-EU rule is not a niche concern. Analysis citing EFRAG estimates suggests that 150 to 200 UK groups could remain in scope, the second-largest national total after the United States.

EU CSRD and ESRS updates

The EU’s Omnibus I package, published as Directive (EU) 2026/470 on 26 February 2026, raised the CSRD threshold to companies with more than 1,000 employees and more than €450 million in net turnover. That cuts the number of companies in scope from an estimated 50,000 to around 5,000. Companies that began reporting for 2024 but now fall below the thresholds may be exempted for 2025 and 2026, depending on how their member state transposes the directive.

The EU has also proposed simplifying the ESRS alongside a voluntary standard for smaller companies outside the CSRD. The proposed revisions are intended to reduce the number of required data points by around 70%, while retaining double materiality. The changes are not final: they will take effect only if the European Parliament and Council approve them and the required legal steps are completed.

Sustainability reporting also overlaps with other EU and UK rules that generate environmental data, including CBAM, the Packaging and Packaging Waste Regulation and extended producer responsibility for packaging. Building one data set that serves all of them saves significant time.

How do you choose the right ESG reporting standard?

There is rarely a single right answer. The best ESG approach starts with legal obligations, then considers who will read the report and what is material to the business.

Materiality, stakeholders and sector priorities

Start with a materiality assessment, because it determines which topics you report on under any standard. Then match standards to audiences:

• Investors and lenders expect financially material disclosures that support investment decisions, which points to UK SRS, the ISSB standards and SASB metrics.
• Customers and procurement teams often ask for CDP responses, carbon data and supplier questionnaires.
• Employees, communities and NGOs want a broad view of impacts, which GRI is designed to provide.
• All businesses should consider their nature impacts, risks and opportunities. Primary nature-dependent sectors such as food, agriculture, construction and extractives should consider TNFD alongside climate reporting.

Geography, regulatory obligations and standards overlap

Map every jurisdiction where you are listed, incorporated or generate significant turnover, and record which regulation applies in each. A UK-listed group with large EU operations may need UK SRS for the annual report, ESRS for an EU subsidiary or group report, SECR for UK energy and carbon, and CDP for customers. Each has its own requirements, timelines and assurance expectations.

The good news is that the main sustainability standards were designed to interoperate. The ISSB and EFRAG have published interoperability guidance between their standards, GRI maps to ESRS, and all three rely on the GHG Protocol for emissions. The practical goal is to collect data once and report it many times.Resource use and waste are often underestimated. ESRS has a dedicated circular economy standard (ESRS E5), GRI has a waste standard (GRI 306), and waste generated in operations is a Scope 3 category under the GHG Protocol. Reliable waste and material data therefore inputs to ESG disclosure, not just an operational metric.

Common interpretation and reporting pitfalls

• Treating a framework or standard as a regulation. Following TCFD or GRI is voluntary and does not, on its own, meet a legal reporting duty. Regulations such as the CSRD and the FCA’s UK Listing Rules specify which standard you must report against.
• Claiming compliance without disclosing reliefs. Under UK SRS, companies using transitional reliefs can still state compliance with UK SRS S2, but only if they disclose which reliefs they used.
• Applying the wrong materiality lens. A GRI impact assessment does not satisfy ESRS double materiality or the ISSB’s financial materiality.
• Relying on estimates for Scope 3 and waste. Spend-based estimates are hard to assure and hide real improvement.
• Chasing ratings rather than decision-useful disclosure. ESG ratings methodologies change. Clear, consistent reporting lasts.
• Assuming the CSRD no longer matters. Large UK groups can still be caught through EU subsidiaries, EU turnover or customer requests.

What are the steps in an ESG reporting process?

Whichever standards you use, the sustainability reporting process follows a similar sequence:

1. Confirm your obligations. Identify which regulations apply in each jurisdiction and from which financial year.
2. Assess materiality. Identify the sustainability risks, opportunities and impacts that matter most to your business and stakeholders.
3. Select and map standards. Choose the standards that meet your obligations and audiences, and map where their disclosure requirements overlap.
4. Build the data foundation. Assign owners and controls for each ESG data set, including emissions, energy, waste, resource use, workforce and governance data. Strong data management at this stage makes every later step easier.
5. Set governance, targets and plans. Agree board oversight, targets and, where relevant, a transition plan.
6. Draft, review and assure. Prepare disclosures, test them against the standards and decide what level of external assurance to seek.
7. Publish and improve. Publish the report, respond to CDP and customer requests, and use feedback to strengthen next year’s data.

Tools such as a life cycle assessment can add product-level evidence where customers or regulators ask for it.