Overview
ISO 20423:2025 - Carbon footprint for seafood - Product category rules (CFP‑PCR) for macroalgae provides a standardized methodology for calculating and communicating the carbon footprint of farmed macroalgae. The standard covers the full aquaculture value chain from seedling production to final consumption, aligning with international life cycle assessment (LCA) principles. It is the first edition (2025) and is intended to support transparent, comparable carbon footprint claims for macroalgae products while not replacing broader environmental or sustainability assessments.
Key topics and technical requirements
- Scope and applicability: Applies specifically to farmed macroalgae products and aquaculture value chains; not a standalone sustainability standard.
- LCA basis: Builds on ISO life cycle standards - ISO 14040, ISO 14044, and product carbon footprint requirements in ISO 14067:2018, and follows ISO 14026 guidance for footprint communication.
- Functional / declared unit: Requires clear definition of the unit used for reporting carbon footprint results.
- System boundaries: Detailed rules for boundaries across stages (farming, harvesting, processing, distribution, consumption) and specific guidance on:
- Cut‑off criteria and excluded processes
- Waste, storage, transport, and capital investments
- Use of recycled materials and co‑products
- Data requirements and quality: Rules for sampling, electricity and fuel data, geographic/time delimitation, validation and transport calculation methods.
- Allocation and impact assessment: Prescribed approaches for multi‑output systems and treatment of fossil vs biogenic carbon.
- Reporting and communication: Requirements to ensure transparent, reproducible carbon footprint claims for macroalgae products.
- Informative annexes: Practical examples and tools (data collection templates, nutrient accounting by elemental mass balance, co‑product allocation examples, LCA modelling cases for kelp, Porphyra, ground seaweed).
Practical applications and users
Who benefits from ISO 20423:2025:
- Macroalgae farmers and aquaculture producers calculating farm‑level CFPs
- Processors, product developers and packagers assessing value‑chain emissions
- LCA practitioners and sustainability consultants modelling macroalgae systems
- Retailers and brands verifying carbon footprint claims
- Certification bodies, policymakers and researchers developing low‑carbon strategies for seafood and aquaculture
Practical uses:
- Produce credible, comparable carbon footprint declarations for marketing or regulation
- Identify hotspots in macroalgae value chains to prioritize emission reductions
- Develop databases, tools and internal improvement programs tailored to macroalgae
- Support low‑carbon innovation and supply‑chain decision making in aquaculture
Related standards
Keywords: ISO 20423:2025, carbon footprint, CFP‑PCR, macroalgae, farmed macroalgae, LCA, aquaculture, product carbon footprint.
