B Corp Climate Action Requirements for Large Companies (V2 Guide)

Quick Answer: For a Large company to become a B Corp, it needs a publicly disclosed, independently verified Scope 1, 2 and 3 emissions inventory from Year 0. From Year 3, it also needs science-based targets and a climate transition plan approved by its highest governing body, usually the board. From Year 5, it reports progress publicly every year. This guide explains each requirement in the order you will meet it.

What changed in the B Corp standards under V2?

B Lab published its V2 standards in April 2025, and since March 2026 new applicants have been able to submit under V2. The biggest change is how you qualify for certification. Under the previous standards, companies worked towards a minimum B Impact Assessment score. Under V2, they must meet every requirement that applies to them across seven Impact Topics.

Climate Action is one of these seven topics. B Lab tailors the requirements by company size, sector and, in some cases, industry. The latest version, V2.2 (February 2026), made no changes to Climate Action. V2.1 added ISO 14064-1:2018 as an accepted standard for measuring greenhouse gas emissions.

For the wider picture, read our B Corp Climate Action guide.

What counts as a Large company for B Corp?

Under B Lab's V2 standards, company size is determined by both the number of workers and annual revenue, with the lower of the two categories applying. B Lab introduced this lower-of-the-two rule in V2.1, effective November 2025.

The relevant size categories are:

For example, a company with 400 workers and $60 million in annual revenue is classified as Medium, because its revenue falls into the lower category.

Worker numbers also need to be calculated in line with B Lab's definitions. If your company is part of a corporate group, you should consider the group's size, ownership structure, operational scope and combined revenue. B Lab provides guidance on how requirements are tailored to each company's context, including subsidiaries seeking independent certification. Your final company size is confirmed during the assessment setup.

Climate Action asks more of larger companies. Verification and science-based targets apply from Large upwards, and X Large companies (1,000 to 9,999 workers) follow the same requirements, so this guide covers them too.

When do the B Corp Climate Action requirements start: Year 0, 3 or 5?

B Corp certification under V2 follows a five-year cycle. Companies undergo an initial audit at Year 0, a review at Year 3 and recertification at Year 5. Larger companies are likely to be audited annually, depending on their circumstances and risk assessment.

The Climate Action requirements are phased across this cycle. Year 0 requirements must be met at initial certification, while additional requirements apply at Years 3 and 5. These are compliance milestones, not necessarily the dates when companies should begin preparing for each requirement.

Step 1: How do you measure and disclose your emissions? (CA1.1)

CA1.1 asks for a documented process to measure your Scope 1, 2 and 3 emissions every year, and a public inventory of the results. B Lab wants a good start that improves each year, not a perfect first attempt.

Your inventory must report emissions in tonnes of CO₂e and include:

• Gross Scope 1 emissions.
• Gross Scope 2 emissions, calculated using both location-based and market-based methods.
• Gross Scope 3 emissions for each relevant category, with a separate figure for each.
• Total emissions calculated twice: once using location-based Scope 2 emissions and once using market-based Scope 2 emissions.

Location-based uses the average emissions of the grid where you use energy. Market-based reflects the supply you have chosen, such as renewable energy certificates or power purchase agreements. See our guides to location vs market-based emissions and Scope 2 emissions.

You also need to:

• List the Scope 3 categories you include and exclude, with a reason for each exclusion. Categories that do not apply to your business or are expected to be insignificant relative to your other emissions may be excluded, provided you document your reasoning.
• Follow the GHG Protocol or ISO 14064-1:2018, as applicable to your business.
• Publish your inventory on your website, either in your annual report, sustainability report or another publicly available report.

Spend-based calculations are permitted for some Scope 3 categories. For others, you need to use at least an average-data or distance-based method. Check Annex D of the GHG Protocol's Scope 3 Calculation Guidance to see which methods are permitted for each category.

Step 2: Does a Large company need its emissions verified? (CA1.2)

Large companies must have their annual GHG emissions inventory independently verified by a third party. Verification must cover Scope 1, 2 and all relevant Scope 3 categories, using the methodology set out in CA1.1.

This is a formal audit. The verifier reviews your methods, emissions factors and data sources, then samples figures across all three scopes and traces them back to underlying evidence such as meter readings, booking records or supplier data. You agree on an assurance level up front: limited assurance is a lighter review, while reasonable assurance involves deeper testing and gives a stronger conclusion. Our guide to ISO 14064 verification covers the full process and what it typically costs. 

Your inventory must be publicly available and verified for the financial year before Year 0, the year of your initial audit. Plan your verification timeline backwards to ensure the inventory is ready in time.

The verifier must be a certification body accredited to a relevant verification standard by a national accreditation body that belongs to the International Accreditation Forum. In the UK, this includes UKAS. Relevant verification standards include ISO 14064-3:2019 and ISAE 3410. Independent means the provider that calculated your inventory, including a carbon accounting platform, cannot verify it.

Step 3: What science-based targets does B Corp require? (CA2.2)

By Year 3, Large companies must have science-based targets in place, with compliance also assessed at Year 5. Targets must be validated by the Science Based Targets initiative (SBTi) or verified by an appropriately accredited, independent third party.

Your targets must include:

• Near-term targets: Emissions reduction targets for Scopes 1, 2 and 3, typically covering the next five to ten years under the applicable SBTi framework.
• Net zero targets: Targets covering Scopes 1, 2 and 3, aligned with a 1.5°C pathway.

You must also record your baseline year and the gross emissions for each scope in that year, providing a reference point against which to measure progress.

B Lab's guidance adds that:

• Targets must be expressed in absolute emissions: Use tonnes of CO₂e, unless you follow an approved sector-specific physical intensity pathway under SBTi.
• Net zero deadlines vary by sector: Your target must be 2050 or sooner, or 2040 for companies in the power and maritime transport sectors.
• Carbon credits cannot replace emissions reductions: Offsets do not count towards your own emissions reductions. High-integrity carbon credits can be used to neutralise residual emissions at net zero.

Step 4: What goes in a B Corp climate transition plan? (CA2.3 and CA2.4)

From Year 3, Large companies need a climate transition plan showing how they will meet their near-term and net zero targets. Under CA2.3, the plan must:

• Set out emissions reduction actions, with clear roles and responsibilities.
• Explain how you'll work with relevant stakeholders.
• Include a viable resourcing plan and disclose the previous financial year's investment in the plan, both as a total and as a percentage of overall investment.
• Explain how your business model supports net zero.
• Be approved by your highest governing body.

Your resources must be sufficient to deliver the plan without exceeding what your business can generate and allocate. You must update the plan when setting new near-term targets, at least every 5 years.

CA2.4 also requires a just transition, except for companies in the Service with Minor Footprint sector. This means considering how your climate plan could affect stakeholders, including those most vulnerable to climate change, and consulting workers and value chain stakeholders, including suppliers at a minimum. You must incorporate their feedback into the plan and allocate dedicated resources and targets to just transition actions.

Step 5: What do Large companies do once the plan is in place? (CA3)

From Year 3

CA3.1 Executive incentives: If you already have an incentive remuneration scheme for your executive team, it must include climate targets, such as emissions reductions or energy efficiency. You must record the monetary rewards linked to climate targets as a percentage of each executive’s salary. B Lab does not require you to create a new incentive scheme. 

From Year 5

CA3.4 Progress and effectiveness: You record progress against your near-term and net zero targets, in tonnes of CO₂e and as a percentage of baseline-year emissions. You must demonstrate progress against your latest plan, assess its effectiveness and set new near-term targets every 60 months. If the plan is not working as intended, record what you have learned, what you will change and how the plan has been updated.

CA3.5 Just transition action: Following consultation with workers and stakeholders, you record the actions taken to support a just transition.

CA3.7 Annual public reporting: You must publish annual progress against your climate transition plan, including your emissions inventory, targets, progress in tonnes of CO₂e and as a percentage of baseline-year emissions, and actions taken. This can be included in your annual report, sustainability report or another publicly available report.

Do law firms, agencies and software companies face fewer B Corp climate requirements?

Three Climate Action requirements do not apply to Large companies classified in the Service with Minor Footprint sector. B Lab defines this sector as companies earning at least 90% of their revenue from services that do not involve selling physical products or require a physical location to deliver them. Examples may include law firms, marketing and communications agencies, and software companies.

The exempt requirements are CA2.4 (just transition consultation), CA3.1 (executive incentives) and CA3.5 (just transition action). All other requirements covered in this guide apply to Large companies in this sector, just as they do to other Large companies.

What mistakes do Large companies make with B Corp climate requirements?

• Leaving verification late. B Lab expects a verified inventory in the financial year before Year 0, so book your verifier early.
• Excluding Scope 3 categories without a reason. Every exclusion needs a written justification.
• Reporting one Scope 2 figure. You need both location-based and market-based.
• Submitting a plan with no money attached. CA2.3 asks for the investment figure.
• Getting approval at the wrong level. It must come from the highest governing body inside your certification scope. For a subsidiary, a parent company's sign-off is not enough on its own.
• Counting offsets as reductions. They do not count towards your targets.

How can Seedling help with B Corp Climate Action?

Seedling is a B Corp-certified carbon management platform, trusted by more than 500 businesses. We help with the parts of Climate Action that take the longest:

• Measure: full Scope 1, 2 and 3 footprints, using activity data rather than spend-based estimates
• Prepare for verification: clear records of your data, assumptions and exclusions for your verifier
• Set targets and a plan: science-based targets and a transition plan, guided by our Carbon Impact Lead, an SBTi Certified Expert
• Engage suppliers: a survey tool that feeds emissions data straight into the platform

Every client gets one-to-one expert support. 

Verification itself must come from an independent third party, so we cannot verify an inventory we have helped build. What we can do is get you ready for it: agreeing scope early, organising your evidence, and introducing UKAS-accredited verification partners. More on our ISO 14064 verification page. 

See how Seedling supports the B Corp Climate Action topic, or speak to our team.

Frequently asked questions