‍Looking for an example Climate Transition Plan? Head straight here.

B Lab Climate Action (v2.1): what Small & Medium vs Large companies need to know

Climate expectations for B Corps have stepped up following the launch of the new standards in 2025. If you’re preparing to certify or recertify, you'll need to know when requirements apply and which ones apply to your company size. This guide focuses on organisations Large and below and keeps the emphasis on practical next steps.

30-second refresher – what's changed in the new B Corp standards?

Minimums, not points – Certification now rests on meeting minimum requirements across seven Impact Topics. That's right - no more scoring! Just a minimum requirement threshold.
Phased over time – Climate Action requirements “switch on” at Year 0, then Year 3, then Year 5.
Size-scaled – Small & Medium follow one path; Large has a higher bar from Year 0.
Verification for Large – Annual independent third-party verification of the GHG inventory.

B Corp updates - Version timeline

If you're struggling to keep up to date with changes, you're not alone. Here's a summary of recent updates, and where you should head for the latest version:

8 Apr 2025 – B Lab launched the new B Corp Standards, replacing the points model with minimum requirements across seven Impact Topics.
12 Aug 2025 – v2.1 published with clarifications and fixes.

The structure of the Climate Action Topic

The new standards use two dimensions to keep everything tidy:

Time – When requirements apply: Year 0, Year 3, Year 5.
Code – What the requirement is:
- CA1.x = Measure & disclose (your GHG inventory + public reporting)
- CA2.x = Plan & targets (Climate Action Plan or Transition Plan, plus science-based targets)
- CA3.x = Implement & report (deliver your plan, just transition, ongoing disclosures)

Size matters – B Lab assigns companies a size category by workers (B Corp's term for employees) or revenue, whichever is higher. Small & Medium share the same Climate Action path; Large has extra requirements from Year 0.

Size boundaries (quick reference)

B Lab assigns size by workers or revenue – whichever is higher. Thresholds are in USD; workers are full-time equivalent (FTE). You can read more about these definitions directly from B Corp here.

Assign the higher category if workers and revenue point to different tiers.

Small & Medium requirements

Plain-English summary – Publish a Climate Action Plan at Year 0. By Year 3, demonstrate and publish progress versus plan. Measuring a full Scope 1–3 footprint isn’t mandated, but it’s the most credible way to evidence Year-3 progress (plus achieve objectives beyond B Corp, like satisfying customer requests for carbon data).

Small & Medium requirements at a glance

Small & Medium B Corp Climate Action Requirements

What does a B Corp Climate Action Plan look like?

In a bid to remove barriers for SMEs in taking climate action, measuring emissions isn't strictly required as part of a valid Climate Action Plan. As Brigitta Nemes, B Lab's Senior Environmental and Governance Standards Manager, explains in a recent article:

"The key expectation is that companies demonstrate real, tangible actions and track their progress, without necessarily needing perfect GHG data."

You need evidence that you are implementing the actions you committed to, and that you’ve reviewed whether they’re working. B Lab’s evidence examples for CA3.3 and CA3.6 include things like:

Records of progress against the plan (annual report, internal scorecards, spreadsheets, project reports)
Proof the actions actually happened (budget/staff time allocated, meeting notes, slide decks, project summaries, stakeholder testimony)
Evidence you reviewed and updated targets/actions as needed (e.g., governing body minutes, updated plan versions)
A public link (website/report/brochure) where progress is disclosed

Actions themselves might entail:

Switching to renewable electricity / energy efficiency projects
Reducing business travel / implementing travel policy
Supplier engagement actions launched

Carbon data can be used as evidence, but for SMEs it’s not required - B Lab accepts implementation + evaluation evidence like the above.

Is a commitment to tackle climate change credible without emissions data?

At the same time, B Lab acknowledges that measuring emissions empowers companies to take climate action informed by reliable data.

1.5 °C is the threshold the IPCC has identified as the upper limit we should be aiming toward globally if we’re to avoid the worst impacts of climate change. The Science Based Targets initiative (SBTi) translated that limit into required action on behalf of businesses: an absolute reduction in full-scope emissions of at least 90% by 2050, offsetting the remainder via high integrity carbon removals.

These are highly specific targets and frameworks, backed by climate science. By contrast, B Lab asks small and medium businesses to commit to:

'supporting the global ambition to limit global warming to 1.5°C'

This is not an explicit commitment to reduce emissions or align with the SBTi. B Lab has chosen not to require SBTi-aligned targets and emissions data in an effort to reduce cost and pressure on smaller businesses. As a small business ourselves, we understand the sentiment! However, low-burden, affordable ways to measure and act do exist. Some companies are concerned that making commitments on climate change without providing carbon data to back it up could risk misleading, and that a lack of data makes it hard to distinguish between B Corp's taking meaningful action versus minimal compliance.

In practice, many SMEs already face stronger demands from customers, partners, investors, and employees when it comes to climate commitments. On this front, B Corp isn’t setting the bar – it’s catching up.

For some, tracking carbon data as a means to inform your Climate Action Plan and evidencing progress might be the best option, even though not strictly required by B Corp for small & medium businesses. It’s the only way to properly understand your emissions, prioritise reductions, and make your plans truly SMART (Specific, Measurable, Achievable, Relevant, Time-bound).

Large Company Requirements

Plain-English summary – Starting with the fiscal year before Year 0, Large companies must measure and publicly disclose a complete Scope 1–3 inventory every year and obtain independent third-party verification annually. By Year 3, you'll need to adopt science-based targets, develop a Climate Transition Plan (check out an example here), and - for some companies - consult on a just transition. Year 5 is about disclosing your Climate Transition Plan progress.

B Corp's Large company requirements at a glance

B Lab's Large Company Requirements - Climate Action Topic

A Note on Verification

Verification must be carried out by an organisation that is independent from whoever prepared your data. So, as your carbon accounting partner, Seedling can't be your verifier too (we'd be marking our own homework).

This means that large B Corps will have to engage another partner for verification of emissions data. As it stands, the verifier will need to be accredited by a body that's an IAF member (e.g. UKAS, DAkkS, COFRAC, ENAC, RvA).

For targets, you'll need external sign-off: either SBTi validation or independent third-party verification that your targets meet 1.5°C science. Inventory assurance and target sign-off are separate obligations – you can use one firm for both if they’re accredited, or choose the SBTi for targets.

There is a cost element here - UKAS-level accreditation has to date largely been conducted by the largest organisations, and cost can reflect that. So, whilst for Small and Medium businesses B Corp has reduced barriers, there is a risk that 'Large' B Corps find themselves facing increasing cost barriers to B Corp ceritifcation.

At Seedling, we're experts at getting your data and supporting evidence in the best possible place for third-party verification, without creating too much extra admin burden. We also team up with verification partners that are best suited to SMEs, keeping the process streamlined and helping to manage cost.

Action checklists

Here's a summary checklist to help you get started.

Small & Medium – today → Year 3

Publish your Climate Action Plan with SMART targets, resourcing, stakeholder engagement and board approval
In year 3: Demonstrate and publish progress versus plan
Consider measuring emissions as a way to keep your progress measurable (and relevant!)

Large – today → Year 3 → Year 5

Follow an annual cycle: measure → disclose → independent verification
In Year 3: adopt science-based targets, publish a Transition Plan, complete just transition consultations, and adapt existing executive remuneration schemes
In Year 5: act on just transition and annually disclose Transition-Plan progress and effectiveness

If your business operates in a sector categorised as 'Service with Minor Footprint,' be sure to refer to our summary table above and B Corp's Climate Action Topic summary to double check where exclusions may apply.

How Seedling helps

The new standards can feel like a big leap, especially if you’re balancing day-to-day business alongside certification. Seedling makes it manageable.

We combine intuitive software with one-to-one expert support to help you:

Capture a complete, GHG Protocol–compliant Scope 1–3 footprint without drowning in spreadsheets.
Turn your data into a credible Climate Action or Transition Plan, with clear targets and a practical roadmap.
Stay on track for B Lab’s Year 0 → Year 3 → Year 5 milestones, so there are no surprises at recertification.

For Large companies, we also remove the headache of verification. We partner directly with accredited auditors – producing the evidence trails, exports and category-level justifications they need. That means one smooth and repeatable process: measure → disclose → verify.

We already support 250+ businesses, including 30+ certified B Corps, to measure accurately, reduce emissions, and meet standards with confidence.

Ready to simplify B Corp Climate Action? Let’s chat about how Seedling can help your team prepare with confidence.

FAQs

Do Small & Medium companies have to measure emissions under v2.1?
No. Small & Medium must publish a Climate Action Plan at Year 0 and publish progress at Year 3. Measurement isn’t mandated, but it’s the most reliable way to demonstrate progress and answer customer due diligence.

What counts as public disclosure?
A page on your corporate website or a report that’s accessible without paywalls or logins. Keep disclosures in a consistent location and update them as required (e.g. annually for CA1.1/CA1.2 incl. fiscal year before Year 0 and annually from Year 5 for transition plan progress under CA3.7).

What’s the difference between a Climate Action Plan and a Climate Transition Plan?
The Climate Action Plan sets commitments, SMART targets, resourcing and governance. The Climate Transition Plan is the operational roadmap that delivers science-based targets with clear roles and investment.

How is company size determined?
By number of workers or revenue, whichever is higher. Moving from Medium to Large changes what applies at Year 0.