What we do
Services.
One core discipline, applied across every stage of the carbon and sustainability accounting lifecycle — from the assurance opinion itself to the advisory work that comes before it.
Each service below is anchored to one of Sustainext's four accredited disciplines. See all disciplines →
Services
- 01Validation & verification
- 02GHG inventory verification
- 03Product carbon footprint
- 04LCA critical reviews
- 05Emission factor verification
- 06Impact modelling
- 07Carbon management advisory
At a glance
Explore all services
Click or hover a service to preview it, then open the full detail below.
Validation & verification
Our core VVB service — independent assessment against your chosen standard, from design through issuance.
Runs through the same seven-stage process every time: pre-engagement to post-issuance monitoring.
This is Sustainext's core accredited service — independent assessment of a carbon project's design (validation) and its delivered performance (verification) against the methodology and standard it's registered under. Validation happens once, at project design; verification recurs at each monitoring and crediting period across the project's lifetime.
Every engagement runs through the same seven-stage process, regardless of project type or registry: pre-engagement, engagement, planning, execution, independent review, decision and issuance, and post-issuance monitoring.
Standards & methodologies
What's included
- Desk review of project design documentation
- Site visits or remote audit, as appropriate to the project
- Technical methodology compliance check
- Independent internal review ahead of opinion issuance
Applies to
- Renewable energy, bio carbon, and Article 6 projects
- Any project registered under a recognized carbon standard
Third-party verification over an organization's or facility's GHG inventory — confirming that reported Scope 1, 2, and, where in scope, Scope 3 emissions are calculated correctly, completely, and consistently against the chosen protocol (the GHG Protocol or ISO 14064-1).
We issue our opinion at the assurance level the engagement calls for — limited or reasonable — and are explicit about which level applies and what it does and doesn't cover. Our approach is risk-based: scoping defines boundaries and criteria up front, then review effort concentrates where a discrepancy could actually change the reported result, rather than re-performing every calculation line by line.
Standards & methodologies
What's included
- Boundary and scope confirmation
- Activity data sampling and evidence checks
- Emission factor verification
- Materiality assessment of any errors found
What you receive
- Independent verification statement (limited or reasonable assurance)
- Transparent documentation of verification activities and findings
- Clear identification of any discrepancies and improvement areas
Independent verification of product- or SKU-level carbon footprint claims, typically calculated under ISO 14067 or the GHG Protocol Product Standard, often feeding into ecolabels, procurement disclosures, or customer-facing footprint claims.
Supported by our GHG Verification discipline where the product footprint rolls up into a broader organizational inventory.
Standards & methodologies
What's included
- Functional unit and system boundary review
- Life cycle inventory data verification
- Emission factor and allocation method checks
Applies to
- Manufacturers and brands publishing product-level footprints
- Ecolabel and procurement disclosure requirements
Independent peer review of life cycle assessment studies against ISO 14040 and 14044, required for any LCA study making comparative public claims. A critical review panel assesses methodology, data quality, and interpretation, independent of the study's authors.
This is a peer-review function rather than an assurance opinion — the review confirms the study meets the standard's requirements, not that Sustainext endorses the study's conclusions.
Standards & methodologies
What's included
- Goal and scope definition review
- Inventory and impact assessment methodology check
- Interpretation and claim consistency review
- Formal critical review statement
Applies to
- Comparative LCA studies intended for public disclosure
- LCA practitioners and commissioning organisations
Not sure which one you need?
LCA critical review, or product carbon footprint verification?
Both provide independent assurance, but they answer different questions. If you only need the greenhouse gas footprint of a specific product, PCF verification is usually the faster, more targeted fit.
LCA critical review
- Reviews the methodology and quality of a full Life Cycle Assessment
- Covers multiple environmental impact categories
- Aligned with ISO 14040 and ISO 14044
- Suited to environmental studies and comparative assertions
Product carbon footprint verification
- Verifies the greenhouse gas emissions associated with one product
- Focuses exclusively on climate impact
- Aligned with ISO 14067
- Suited to product carbon claims and customer-facing communication
Assessment of the emission factors an organization or project uses as inputs to its GHG calculations — confirming they're sourced appropriately, applied correctly, and updated as underlying data such as grid emission factors, fuel properties, and activity-specific factors changes.
Many organizations still rely on generic industry-average factors by default, which understates the value of genuine supplier-level improvement. Verifying supplier- or location-specific factors lets year-on-year comparisons actually reflect real change — often resulting in a lower, more defensible reported figure than an industry average would produce.
Standards & methodologies
What's included
- Source and vintage check against current published factors
- Applicability review by activity type and geography
- Consistency check across reporting periods
Applies to
- Corporate inventories and project baseline calculations
- Multi-year or multi-geography reporting programmes
Review of the models and assumptions behind projected environmental outcomes — used at project design stage to assess additionality and expected impact, or by corporates modelling the projected effect of a planned intervention before it's implemented.
Because this work happens before an outcome exists to measure, the review focuses on whether the model's assumptions and inputs are defensible — not on confirming a result that hasn't happened yet.
Standards & methodologies
Exploring new interventions
- Assess expected impact and additionality before committing capital
- Build the case for internal stakeholder support and ROI
Managing existing interventions
- Assess programmes already underway against original assumptions
- Identify monetization or co-investment opportunities
Carbon management advisory
Advisory — non-accreditedGuidance on measurement systems, methodology selection, and reporting readiness ahead of formal verification — helping a client prepare a defensible inventory or project design before it goes through independent assurance.
Typically covers
What's included
- Methodology and standard selection guidance
- Measurement system and data-readiness review
- Pre-verification gap assessment
Applies to
- Organisations preparing for their first formal verification
- Project developers scoping a methodology before design
Need a service that isn't listed here?
Tell us what you're trying to verify or report, and we'll scope the right engagement.
Start a conversation