Brent goose in flight, toward the camera, over white breaking waves in the sea below, with a faded view of wind turbines in the far distance

Blue Carbon

Marine ecosystems capture and lock away huge quantities of carbon. However, the habitats and species responsible for this process are under threat. Protecting and restoring them would benefit nature as well as people.

What is Blue Carbon?

Close up view of a grey plover, walking along a wet, sandy beach, with a blurred background

Marine and coastal animals and habitats, including saltmarsh, mudflats, kelp forests, seagrass beds, living reefs or subtidal sediments all capture and lock away carbon. This is called ‘blue carbon’.


Marine habitats dense in vegetation are particularly efficient at locking away carbon. Globally, they store a similar amount of carbon each year to land habitats despite the fact they cover 0.05% of the same area. 

Threatened carbon stores

Close up view of three oystercatchers walking on  a wet sandy beach, with a blurred background

  • 35% of UK seagrass meadows have disappeared since 1980
  • An area equivalent to 15,000 football pitches of saltmarsh has been lost since World War II and a another 5,600 pitches worth are at risk, mostly from coastal development and erosion
  • Kelp forests are under stress from ocean warming
  • Overfishing is removing carbon-storing marine organisms on a huge scale.
  • Bottom towed fishing gear are damaging the seabed and sediments storing carbon

Restoring coastal ecosystems

View across a saltmarsh creek, with meandering streams of water through saltmarsh mounds covered in grasses

Unlike the majority of land habitats, most marine ecosystems (with exceptions like saltmarsh) cannot be actively restored, only allowed to naturally regenerate.


The RSPB developed valuable insights into the saltmarsh restoration process from 25 years of work. Protecting marine ecosystems is vital as we cannot easily replace them once destroyed. Governments must lead the restoration efforts around the country and increase the protection of these important habitats and species which depends on them.

Preserving offshore ecosystems

View out across calm blue waters at Luce Bay, with a small rock island standing up through the water in the centre of view

Carbon stores, such as kelp forests and sediments, are under growing pressures from climate change and disturbance including fishing and offshore developments. Unlike for coastal ecosystems, most offshore marine habitat restoration projects are still experimental and extremely costly, with mixed results. So they must be allowed to recover by removing pressures and protecting them.

Governments must step up

Flock of adult little terns in flight over a bright blue sea, Winterton-on-Sea, Norfolk

UK Governments have a crucial role to play in the conservation of blue carbon stores, including:

  • Reduce and where possible remove pressures upon blue carbon stores
  • Protect stores through the designation of marine protected areas (MPA) and highly protected marine areas (HPMA) and enforcement of management measures within the MPA network
  • Support research and investment to fill data gaps and increase the monitoring and restoration of blue carbon stores