An introduction
What is blue carbon?
Blue carbon is carbon taken up and stored by ocean and coastal ecosystems. Some of the carbon captured by plants accumulates in soils and sediments as well as living vegetation.
This guide focuses on coastal ecosystems discussed in conservation, restoration and carbon accounting.
NOAA — What is blue carbon? ↗
The main coastal ecosystems
The IPCC Wetlands Supplement covers mangroves, tidal marshes and seagrass meadows within its coastal wetlands guidance.
- Mangroves
- Forests along tropical and subtropical coasts.
- Salt marshes
- Coastal wetlands with herbaceous plants, influenced by tides.
- Seagrass meadows
- Underwater communities of flowering plants, including eelgrass.
Seagrass and seaweed are different
Seagrasses are flowering plants; seaweeds such as kelp are algae. Seaweed takes up carbon, but uptake is not the same as long-term storage. Assessments need to establish where the carbon goes and how long it remains there.
IPCC — Ocean and coastal ecosystems ↗What to check in a project
These are our editorial prompts for comparing sources and initiatives, not a complete set of certification requirements.
- Measurement boundaries
- Does the estimate include soils and sediments, or only vegetation? Check area, time period and uncertainty.
- Additionality and durability
- Compare outcomes with what would have happened without the project. Look for re-release risks and long-term management plans.
- People and ecosystems
- Check community participation, benefit sharing and biodiversity impacts alongside carbon estimates.
How it relates to the blue economy
The blue economy connects ocean health with economic activity and livelihoods. Blue carbon is one part of this broader picture, linking coastal conservation with climate action.
Overview →Blue carbon in Japan
Seaweed beds and tidal flats
Japanese environment and transport ministry guidance includes seaweed beds and tidal flats alongside seagrass, marshes and mangroves. Coverage and accounting methods differ between international guidance and domestic schemes; check the applicable source.
Japan’s ecosystem overview ↗What is J-Blue Credit?
JBE manages a scheme assessing CO₂ uptake and storage by coastal ecosystems. Certification and issuance follow third-party committee review of activities already carried out.
The official portal provides application guidance, certification records and information for buyers and holders.
JBE scheme and application information ↗Planning local conservation and restoration
Japan’s Satoumi guide covers surveys and evaluation of seagrass beds and tidal flats, together with staffing, funding and use of evaluation results to sustain local work.
Satoumi evaluation guide ↗Common questions
Does restoring a habitat automatically create credits?
Restoration and certification are separate steps. Accounting, application and review must follow the scheme’s requirements. Check current JBE guidance for eligibility and procedures.
Source (Japanese) ↗What should be assessed beyond carbon?
Consider habitat, water quality, local uses and the capacity to sustain the activity. The Satoumi guide helps readers identify evaluation methods suited to their objectives.
Source (Japanese) ↗Frequently asked questions
What is the blue economy?
The World Bank describes it as the sustainable use of ocean resources for economic growth, improved livelihoods and jobs while preserving ocean ecosystem health.
What is blue carbon?
It is carbon captured by ocean and coastal ecosystems. In coastal wetlands, soils and sediments can be important storage locations alongside living vegetation.
Why is seaweed blue carbon still under study?
Seaweed takes up carbon, but uptake alone does not establish long-term storage. Assessments need to examine where the carbon goes and how long it remains there.
What is J-Blue Credit?
It is a carbon-credit scheme managed by the Japan Blue Economy Association (JBE) for CO₂ absorption and storage in coastal and marine areas. Consult JBE for current requirements and certification information.
Read JBE’s J-Blue Credit informationWhere can I find initiatives in Japan?
Use this site’s initiative directory and filter by Japan. Also check current materials directly from the organisations that run each initiative or scheme.
Sources and related initiatives
Article updated: 26 September 2026
Source summaries and editorial reading notes do not imply expert review or peer review.