Carbon reporting frameworks compared: SECR, CSRD, PPN 006, B Corp, CDP, EcoVadis, SBTi and UK SRS

Introduction

A client sends over a carbon questionnaire. A public sector tender asks for a Carbon Reduction Plan. The finance team notices SECR applies this year, and the board asks about a science-based target. Carbon reporting rarely arrives as one requirement; it arrives as several, each with its own acronym.

This guide compares eight carbon reporting frameworks businesses are regularly asked about: four mandatory for specific groups of companies (SECR, PPN 006, the UK Sustainability Reporting Standards and the EU's CSRD), and four driven by customers, investors or certification choices (B Corp, CDP, EcoVadis and the SBTi). For each, we cover what it is, who uses it and what carbon data it needs, with a link to our detailed guide.

What is the difference between a standard, a framework, a rating and a certification?

"Carbon reporting framework" is used as a catch-all, but the eight schemes in this guide are different kinds of thing. Knowing which is which tells you what you are being asked for, who decides whether you have met it, and how much flexibility you have.

• Standards set the rules for how something is measured or disclosed. The GHG Protocol Corporate Standard is the global rulebook for emissions across Scopes 1, 2 and 3, and underpins almost every scheme below. ISO 14064-1 covers similar ground for third-party verification, and the two bodies are working towards a single aligned standard. The UK SRS and the SBTi's standard also sit in this group.
• Regulations and policy frameworks set out who has to report what, and where. Examples include SECR and PPN 006 in the UK, and CSRD in the EU. 
• Disclosure and ratings platforms collect your data and score it. CDP and EcoVadis both work this way, and most companies respond because a customer or investor has asked them to.
• Certifications are awarded once an independent party confirms you meet a defined set of requirements. B Corp is a well-known example.

Why compare them all together?

Often because they turn up together, not one at a time. A manufacturer in the UK might have to report under SECR, complete EcoVadis for one customer and CDP for another, and need a Carbon Reduction Plan for a public sector bid, all in the same year.

The thing they have in common is the data: all eight draw on greenhouse gas data in line with the GHG Protocol (for B Corp, mainly larger companies). Each asks for a different part of it, in its own format, which is why it pays to treat your footprint as one dataset you maintain properly.

How do these carbon reporting frameworks compare? 

What do these carbon reporting frameworks ask for?

What is SECR?

Streamlined Energy and Carbon Reporting (SECR) is a UK requirement for certain companies and LLPs to disclose energy use and greenhouse gas emissions in annual reports. It applies to quoted companies, and to unquoted companies and LLPs meeting at least two of three tests: turnover above £36m, balance sheet above £18m, or 250+ employees.

These thresholds weren't raised when the Companies Act thresholds changed in April 2025, so a company can be medium-sized for its accounts but still fall within SECR's scope. Businesses using 40,000 kWh or less can file a low-energy statement instead.

SECR is under review: the government's May 2026 review recommended keeping it with amendments, including clearer guidance and a standard template.

The role of carbon reporting: SECR covers Scope 1 and 2 emissions, plus an intensity ratio and efficiency actions. Quoted companies report global energy and emissions; unquoted companies and LLPs report UK energy and emissions, including business-travel Scope 3, plus the prior year's figures after year one. Read our SECR reporting guidance for more detail.

What is CSRD?

The Corporate Sustainability Reporting Directive (CSRD) is the EU's sustainability reporting regime. Following the Omnibus I Directive, in force since 18 March 2026, EU member states have until 19 March 2027 to transpose the revised rules.

EU companies and groups exceeding 1,000 employees and €450m in net turnover are in scope, with first reports covering FY2027. Non-EU parent groups are also in scope if they generate more than €450m in EU turnover over two consecutive years and have a qualifying EU subsidiary or branch generating more than €200m. First reports for non-EU groups are due for FY2028.

The role of carbon reporting: reporting follows the European Sustainability Reporting Standards (ESRS), applying to financial years from 1 January 2027. Where climate is material, ESRS E1 requires Scope 1, 2 and significant Scope 3 emissions, checked under limited assurance. Read our CSRD guide for more detail.

What is PPN 006?

Procurement Policy Note 006 sets out how government departments take account of suppliers' Carbon Reduction Plans (CRPs). It applies to contracts above £5m a year, including VAT, under the Procurement Act 2023. The NHS's own Net Zero Supplier Roadmap builds on PPN 006: from April 2027, contracts of £5m or more move to a wider tier covering all Scope 3 categories, not just the five under PPN 006.

The role of carbon reporting: the CRP is built on a UK footprint following the GHG Protocol, covering Scope 1 and 2 plus five Scope 3 categories (transport, waste, business travel, commuting and distribution). It must commit to Net Zero by 2050, be board-approved and published on your UK website, updated yearly. See our guide to PPN 006 Carbon Reduction Plans and free CRP template.

What does B Corp certification require?

B Corp certification is awarded by B Lab. The B Lab Standards V2, used for certification from 2026, replace the old 80-point score with minimum requirements across seven Impact Topics, including Climate Action, audited by an independent third party.

The role of carbon reporting: requirements scale with company size. Smaller companies must publish a climate action plan without a mandatory emissions inventory. Larger companies must measure and disclose Scope 1, 2 and relevant Scope 3 emissions yearly, verified, then set science-based targets and a plan. Read our B Corp Climate Action guide.

What is CDP?

CDP (formerly the Carbon Disclosure Project) runs a global environmental disclosure system. Companies answer an annual questionnaire, usually because an investor or large customer requested it, and receive a score from A to D-. The 2026 scoring deadline was 16 September.

The role of carbon reporting: the climate questions use the ISSB's IFRS S2 as their baseline, asking for emissions across all three scopes, how they were calculated and verified, plus targets and a transition plan. Our guide to CDP reporting and CDP scoring explainer go into more depth.

What is EcoVadis?

EcoVadis is a ratings platform that large buyers use to assess suppliers. Companies upload evidence across four themes and 21 criteria, and receive a score out of 100 valid for 12 months. Medals run from Bronze (top 35%) to Platinum (top 1%); a medal isn't a certification.

The role of carbon reporting: Energy Consumption and Greenhouse Gas Emissions is one of the Environment criteria. Only documented evidence counts, and reporting is credited only where it covers at least 95% of the assessed scope. See what EcoVadis is and how to improve your EcoVadis score.

What is the SBTi?

The Science Based Targets initiative (SBTi) develops standards for corporate emissions reduction targets aligned with climate science. More than 11,000 companies have validated targets. Version 2.0 of its Corporate Net-Zero Standard was published on 11 June 2026; companies can submit under either version until 31 January 2028, after which Version 2.0 becomes mandatory.

The role of carbon reporting: science-based targets are built on a greenhouse gas inventory covering Scope 1, 2 and relevant Scope 3. Version 2.0 places more emphasis on implementation and transition planning. Supplier engagement targets commit a company to getting a share of suppliers to set their own targets, which also helps meet B Corp's Climate Action requirements. See our SBTi V2.0 explainer and guide to the validation process.

What are the UK Sustainability Reporting Standards (UK SRS)?

The UK Sustainability Reporting Standards (UK SRS) are the UK-endorsed versions of the ISSB's international standards: S1 covers general disclosures, S2 covers climate. Final standards were published 25 February 2026 for voluntary use. The FCA has confirmed comply-or-explain rules for companies in specified listing categories, from accounting periods starting 1 January 2027. Transitional relief defers Scope 3 by one year and S1 by two. The government's Modernising Corporate Reporting consultation is open until 30 November 2026.

The role of carbon reporting: UK SRS S2 covers Scope 1, 2 and 3 emissions alongside climate risks and transition planning. Businesses outside the FCA rules may still face requests from listed customers for emissions data. Read our UK SRS guide for more detail.

What are the key dates to watch?

Which sustainability reporting frameworks apply to your business?

Most businesses fall into two or three of the rows below. Mandatory schemes depend on where you operate, your size and legal form; the rest depend on who you sell to and who invests in you.

Outside the UK and EU, similar rules are emerging, such as California's SB 253 and Australia's ASRS, built on the GHG Protocol or the ISSB's standards.

A sensible order is to cover the legal requirements first, then the requests with a contract attached, then the voluntary commitments. Building all of them from one footprint saves you from reconciling slightly different numbers for each audience.

How can Seedling help with carbon reporting?

Most of the effort happens before the report is written: gathering the right data, calculating it correctly and keeping the method consistent year on year. Seedling is built around doing that once, properly, and reusing it.

• One full-scope footprint. We measure Scope 1, 2 and 3 in line with the GHG Protocol, using activity data wherever possible rather than spend alone, so your figures reflect real change.
• One dataset, many outputs. The same footprint feeds SECR, PPN 006, B Corp, CDP, EcoVadis, customer questionnaires and UK SRS S2 disclosures.
• Targets and a plan to hit them. We help you set SBTi-aligned targets and model a reduction plan you can report progress against.
• Better Scope 3 data. Built-in employee and supplier surveys bring in primary data on commuting, homeworking and supplier emissions.
• A named expert. Every client has a dedicated carbon expert to call on for anything a framework throws up.

More than 500 businesses use Seedling, over 500,000 tonnes of CO2e have been measured on the platform, and 95% stay with us year on year. If you're handling more than one framework above, book a demo and we'll show you how one dataset covers them.

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