Blue Carbon: what is the potential for marine natural solutions to climate change?

This blog is written by Kirsten Carter, The RSPB’s Principal Marine Policy Officer

‘We need Nature Based Solutions to climate change’ is a phrase you might have heard before. This is all about harnessing the power of nature to mitigate carbon emissions and tackle climate change. There’s lots of different solutions with nature at its heart – from planting trees to restoring bogs and peatlands. These solutions are about using our land in a different way that increases biodiversity and reduces carbon emissions. However, the focus is often on how our land can contribute to tackling climate change, what about the sea? What is the potential for natural solutions in our marine environment to mitigate climate change? This new study explores this question by highlighting the carbon capture and storage potential in natural systems within the English North Sea.

The role of our seas in tackling Climate Change

The new report commissioned by The North Sea Wildlife Trusts, WWF, Blue Marine Foundation and the RSPB demonstrates the need to better link biodiversity protection and enhancement with potential for natural solutions to climate change within the marine environment.

It’s the most comprehensive analysis of its kind to date and demonstrates the role the English North Sea can play in the fight against climate change, if this environment is well protected. This includes managing Marine Protected Areas with biodiversity and climate change in mind, which would support the protection and restoration of a resilient marine environment able to effectively mitigate against the impacts of climate change.  

Blue Carbon in the English North Sea

‘Blue carbon’ refers to the carbon captured and stored in coastal and marine ecosystems, particularly by marine animals, plants, sediments and vegetated habitats such as saltmarshes, seagrass meadows, wetlands and seaweed.  Vegetated coastal ecosystems store a comparable amount of carbon each year to land-based ecosystems. Yet, the extent and condition of coastal and marine habitats has declined and continues to be  under threat across the UK. Over 8,000 ha of saltmarsh has been lost since World War II and another 3,000 ha are at risk, primarily from human development and increased coastal erosion. Further35% of seagrass meadows have been lost since 1980 and kelp forests are under growing stress from ocean warming. These habitats and ecosystems all help to keep the marine environment healthy and resilient as well as storing ‘blue carbon’.

This new report provides a breakdown of carbon stores and sequestration capacity within the English North Sea, which includes 26 Marine Protected Areas, such as Flamborough Headland, with the RSPB Bempton Cliffs and the Dogger Bank, a key area for sandeels and foraging seabirds. The report includes an ecosystem-scale carbon inventory of the key rates and sequestration capacity of each ‘blue carbon’ habitat, providing a tool which can guide conservation and restoration efforts in the region in future.

What are the blue carbon stocks? The report shows an incredible 100.4 million tonnes of carbon stocks were found within the English Sea region alone. To put this into context, UK forests are estimated to store 529 million tonnes carbon. The report shows that 98% of this amount is located within the top 10 cm of sublittoral mud and sand/mud seabed sediments. This highlights, in particular a need to protect the surface area of sediment which can store the most carbon, but is also at the greatest threat from physical disturbance. These sediments are likely to be tens to hundreds of metres in depth and so these figures should be considered an underestimate of the total carbon stored in the seabed sediments. Sediments storing blue carbon are under stress from human pressures such as aggregate dredging, infrastructure development, and fisheries, including use of heavy bottom towed trawls and dredges which will come into contact with the seafloor, disturbing, and in extreme cases, destroying blue carbon ecosystems.

How can Marine Protected Areas help?

The Marine Protected Areas featured within this study cover over 57 000 km2, representing 50% of the English North Sea. Stocks of carbon within the habitats and surface sediments of these sites are estimated to 51,9% of the total organic carbon and 42.1% of the total inorganic carbon stored across the study area. This demonstrates there is considerable potential to protect, manage and increase carbon stocks and sequestration rates in coastal and marine environments, which could in part be achieved through effective management of our Marine Protected Areas.

However, we know that almost all of these sites are still subjected to broad scale disturbance. We need to integrate the carbon value of marine habitats into decisions around marine management as this could enhance their capacity to provide a carbon sink as well as support more healthy and resilient marine environments. In cases where an MPA supports important blue carbon habitats, there should be specific management measures and objectives to protect these stocks. .Beyond improving the management of existing protected sites, , , some important areas for blue carbon stocks, such as the Devil’s Hole region, do not lie within an MPA designation and so remain vulnerable to degradation. There is a huge opportunity here to protect significant carbon sinks from further disturbance.

Protecting and restoring marine species and habitats provides multiple benefits for nature-based solutions to the climate and nature emergency. Beyond their blue carbon storing qualities, restoring these marine habitats would help to halt  biodiversity decline and build resilient marine environments for both wildlife and people to enjoy.

Read the full report here to find out more

Want to learn more about Blue Carbon and restoring marine environments?

- Read the Shifting Gears report to find out more about the role of our seas and explore how developing climate smart fisheries can tackle climate change

- Take a look at our interactive Story Map on intertidal habitats to find out more on the RSPBs work to create, restore and protect important blue carbon coastal ecosystems