Blue carbon
Marine ecosystems around the UK can both increase and decrease atmospheric carbon dioxide levels. Carbon loss and gain globally by these ecosystems has the potential to influence climate change. This POSTnote summarises the marine ecosystems in the UK that contribute to these processes, their current and potential future extent, and pressures on them.
DOI: https://doi.org/10.58248/PN651
Blue carbon has the potential to contribute to the UK’s carbon sequestration efforts. However, damage to blue carbon habitats may also result in release of carbon, potentially contributing to climate change. Blue carbon policy seeks to maximise the sequestration and storage of carbon within habitats.
Investment in, and protection of, blue carbon systems is not as developed as in woodlands and peatlands and most are not currently included in the UK’s national GHG inventory. This is in part the result of scientific uncertainties about the carbon benefits of blue carbon habitats, as well as uncertainties about the extent of those habitats in UK waters. However, understanding of the carbon sequestration and storage in blue carbon habitats is increasing, and plans and legislation are evolving to reflect this. The UK’s new regional Marine Plans include considerations of the blue carbon value of their waters, and the UK Government is considering blue carbon value in the designation of pilot sites for a new category of highly protected marine areas. Private investment is currently constrained by lack of a UK carbon code for blue carbon habitats, but the UK Government has funded the development of such a scheme for saltmarshes.
In addition to carbon sequestration and storage, blue carbon habitats provide a range of co-benefits of value. These include improved water quality, flood protection, protection from coastal erosion, increased fish and shellfish abundance, and increased biodiversity.
Key points
- ‘Blue carbon’ refers to carbon that is stored in marine ecosystems, where management of those ecosystems impacts that carbon.
- These ecosystems sequester and store around 2% of UK emissions per year.
- Marine ecosystems also provide other benefits such as biodiversity, flood protection, and support for valuable fish and shellfish populations.
- Disturbance of marine ecosystems may result in release of stored carbon and thereby contribute to climate change, but the exact volume released is unknown. The UK Government will pilot new approaches to protecting blue carbon.
- Investment in blue carbon projects in the UK is limited by a lack of verifiable standards and scientific evidence, although development of codes is ongoing.
- Blue carbon projects are not a substitute for substantial emissions reductions.
Professor John Baxter, Scottish Blue Carbon Forum
Laura Harland, DEFRA
Professor Gideon Henderson, DEFRA*
Robert Paver, DEFRA*
Dr Caitlin Burns, Environment Agency*
Eve Leegwater, Environment Agency
Dr Tammi Warren, Department of the Environment and Natural Resources Bermuda*
Dr Joanna Pitt, Department of the Environment and Natural Resources Bermuda
Cathy Tilbrook, NatureScot
Caitlin Cunningham, NatureScot
Ed Salter, Crown Estate
Lisa Benson, CEFAS*
Dr Ruth Parker, CEFAS*
Dr Stuart McLanaghan, Seafish*
Tim van Berkel, Cornish Seaweed Company
Professor Jason Hall-Spencer, University of Plymouth
Professor Sian Rees, University of Plymouth*
Professor William (Bill) Austin, University of St. Andrews*
Dr Edward Tipper, University of Cambridge
Emma Ward, University of Portsmouth*
Dr Kate Hendry, University of Bristol
Professor Carlos Duarte, King Abdullah University
Professor Rick Stafford, Bournemouth University*
Professor Michael Burrows, SAMS
Professor Heidi Burdett, Heriot Watt University*
Professor Michael Kaiser, Heriot Watt University
Professor Richard Lampitt, National Oceanography Centre
Professor Hilary Kennedy, Bangor University*
Dr Nick Kamenos, University of Glasgow*
Professor Rob Marchant, University of York
Dr Dan Smale, Marine Biological Association*
Dr Graham Epstein, University of Exeter*
Daniel Crockett, Blue Marine Foundation
Dr Renee Kirkvliet-Hermans, IUCN
Chris Tuckett, Wildlife and Countryside Link
Dr Peter Richardson, Marine Conservation Society
Anna Gelderd, Marine Conservation Society*
Hannah Freeman, Wildfowl and Wetlands Trust*
Alice Millest, Finance Earth
* denotes people and organisations who acted as external reviewers of the briefing