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Charities urge stronger protection for Irish Sea and Welsh Coast as landmark reports reveal amount of carbon stored in seabed habitats for the first time

Terry Whittaker/2020VISION

A landmark report published today by a coalition of nature charities provides the first estimate of the carbon stored in seabed habitats in the Irish Sea and along the Welsh Coast. 
  • A new series of reports – The Blue Carbon Mapping Project – provides the first estimate of carbon stored in UK seabed habitats, including in Marine Protected Areas (MPAs).
  • 15.7 million tonnes of organic carbon are stored in just the top 10cm of seabed sediments (principally made of mud) in the Irish Sea and Welsh Coast Region, plus coastal vegetated habitats including saltmarshes and seagrass beds. 70% of this carbon is stored in MPAs.
  • Seabed disturbances, including from bottom trawling and offshore development, are identified as threats to blue carbon stores, as nature charities call for stronger protections for UK seas.

The report is part of The Blue Carbon Mapping Project, completed by the Scottish Association for Marine Science (SAMS) on behalf of WWF-UK, The Wildlife Trusts and the RSPB. The series of reports mean the UK is the first nation to map and estimate the amount of carbon stored in its seabed habitats, including within Marine Protected Areas (MPAs).

The report reveals that 15.7 million tonnes of organic carbon* are stored in just the top 10cm of seabed sediments – principally made of mud – in the Irish Sea and Welsh Coastal Region. 

The Irish Sea and Welsh Coastal Region covers 43,112 square kilometres. This vast area is host to habitats that capture and store carbon, known as ‘blue carbon’. They include seabed sediments (made of mud, silt and sand), vegetated habitats (seagrass meadows, saltmarshes, kelp forests and intertidal seaweeds), maerl beds and biogenic reefs, such as mussel beds and honeycomb worm reefs.

Carbon is primarily absorbed by phytoplankton, which drift to the bottom of the sea when they die and are added to seabed sediment. The research analysed the storage capacity of just the top 10cm of sediment. Some sediments are hundreds of metres thick and contain millennia’s worth of carbon, so the total carbon stored will be far greater.

The Blue Carbon Mapping Project highlights how physical disturbances to the seabed, including from human activity such as bottom trawling, as well as moorings and offshore developments, pose threats to blue carbon stores. Disturbing seabed habitats can release large amounts of carbon into the atmosphere, worsening climate change.

WWF, The Wildlife Trusts, and the RSPB are calling on governments across the UK to strengthen protections for valuable blue carbon stores – including in MPAs – by minimising the impacts of human activities on the seabed. Most MPAs were not designated to protect blue carbon, and failing to protect these areas from disturbance could threaten climate and biodiversity goals – including net-zero and protecting 30% of seas by 2030.

WWF, The Wildlife Trusts & RSPB call for:

Better management of MPAs

  • Ensure that all MPAs are protected from destructive activities that damage blue carbon habitats and threaten marine life.
  • Account for both carbon and biodiversity in designating new protected areas, to support ecosystem resilience and the role seas play in climate mitigation.

Improved strategic planning of activities in UK seas

  • Consider blue carbon in UK marine plans, avoiding damaging activities in MPAs and other key areas for blue carbon and wildlife that are not protected.
  • Minimise the impacts of fishing and developments by undertaking blue carbon impact assessments.
  • Support a just transition for fishing industries away from activities that damage the seabed.

More investment and research on protecting blue carbon

  • Allocate funding to restore habitats including seagrass beds and saltmarshes.
  • Support research and monitoring of blue carbon dynamics.
  • Add seagrass and saltmarsh to the Greenhouse Gas Registry to track and monitor emissions.

Penny Nelson, Ocean Recovery Advocacy and Policy Lead at WWF Cymru, says: "This report has highlighted the tremendous value of Welsh marine habitats in helping to mitigate the growing impacts of climate change. These new insights into the areas where large quantities of carbon are stored must be used by Welsh Government to protect existing marine habitats to ensure this carbon remains locked away for future generations. It also emphasises the urgency for Welsh Government to fulfil their Programme for Government commitment to establish a scheme to protect and restore seagrass across Wales."

Dr Mat Lundy, Head of Marine Recovery at Ulster Wildlife, says: "The vital role our seas play in storing carbon is often overlooked. To maintain the health of our marine ecosystems and ensure they continue to meet our needs, careful and strategic planning of their use is essential. This report provides valuable insight into the areas that help store carbon, offering an opportunity to take action. With DAERA’s Blue Carbon Action Plan and the Review of the Marine Protected Area Strategy, we can focus efforts on restoring and improving Northern Ireland's blue carbon habitats. By investing in these initiatives, we can boost the environmental benefits of our seas and help tackle the climate crisis for future generations."

Joan Edwards, director of marine policy for The Wildlife Trusts, says: “These world-first reports reveal the enormous value of UK seas while highlighting that many areas need far better protection. We need strategic decision-making from policymakers to recognise the value of blue carbon by minimising the impact of human activities on the seabed. Damaging activities such as bottom trawling and large development must not take place in protected areas. This research gives the UK an opportunity to lead the world in protecting blue carbon and marine biodiversity.”

Kirsten Carter, head of UK marine policy at the RSPB, says: “Accelerating efforts on land to tackle the nature and climate emergency is critical, but we must not underestimate the role of UK seas. This report is a game-changer for our knowledge of the marine environment and a huge asset for decision-makers. Now we need them to act on its findings. To meet net-zero and stop biodiversity decline we must work with nature, not against it. This means restoring habitats, properly planning offshore development, and investing in protected areas to safeguard wildlife and keep blue carbon locked up.”

Professor Mike Burrows, Scottish Association for Marine Science, says: “Understanding how much and where our marine carbon is stored is vital for guiding efforts to maintain and protect the capacity of coastal and seabed habitats to continue to serve this function. Saltmarshes and seagrass beds are significant carbon storage hotspots, while kelp beds and especially phytoplankton contribute large amounts of organic carbon annually. However, the exact fraction of this carbon that is stored in sediments remains uncertain. By consolidating various information sources, we have gained valuable insights into our coastal seabed. This process has also highlighted significant gaps in our knowledge regarding the rates of carbon accumulation in sediments.”

*Please note that organic carbon should not be converted into carbon dioxide equivalent in this instance due to the complex interaction of atmospheric carbon and the ocean.

Read the technical summary for the Irish Sea and Welsh Coast region 

Read the full scientific report for the Irish Sea and Welsh Coast region 

ENDS

Key findings: Irish Sea and Wales Coast Region

• Organic carbon storage and accumulation: The Irish Sea and Welsh Coast Region stores an estimated 15.7 million tonnes of organic carbon (produced by living things such as phytoplankton, kelp, and seagrass) in the top 10cm of seabed sediments and vegetated habitats, with over 94% in seabed sediments, principally mud. Up to 1.3 million tonnes of organic carbon could be added annually to sediment stores where natural sedimentation is 
able to occur.
• Importance of coastal habitats: While coastal habitats of saltmarshes and seagrass beds occupy only 5% of the area, they store 13% of the organic carbon – over 420,000 tonnes. Coastal vegetated habitats in the region accumulate up to 250,000 tonnes of carbon per year (18% of the total).
• Areas designated for marine protection in the Irish Sea and Welsh Coast Region cover 31,177 km2 and contain approximately 70% of the total organic carbon (over 10 million tonnes) in the region. This is higher than the UK-wide figure (43%).
• The biggest threats to blue carbon stores come from activities that physically disturb the seabed, predominantly from bottom trawling, but also from moorings and developments at sea and in coastal regions. Bottom trawling can penetrate the seabed, potentially releasing carbon into the atmosphere and harming marine wildlife. 
• Ocean acidification and various climate change impacts pose mixed effects on blue carbon capture, potentially harming calcareous organisms, such as molluscs, while potentially benefiting some photosynthetic species including seaweeds and seagrass.
• Oceans catch carbon eroded from land: Seas store carbon that has been eroded on land and transported via waterways such as rivers. Blue carbon stores are the last chance to capture this carbon and prevent it from being released into the atmosphere. 

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