The potential for carbon storage in the marine environment is vast, yet not always given the consideration it deserves.

What is blue carbon?

When asked what the principal natural stores of atmospheric carbon are, most people would suggest terrestrial habitats, most likely rainforests, peatlands and woodlands. However, despite the huge potential for carbon storage on land, it is in fact marine habitats that store the greatest amounts of ‘blue’ carbon. To put this in context, it has been estimated that the carbon storage in Scotland’s marine sediments alone equates to 52% of Scotland’s 2011 carbon emissions.

Marine ecosystems store carbon in both living (e.g. animals and plants) and non-living (e.g. shells and skeletons) material. Some of these stores can lock carbon away for thousands of years (e.g. calcium carbonate shells and maerl beds), while other stores are a more short-term, monthly basis (e.g. kelp forests and seagrass beds).

The benefits of protecting blue carbon

Whether short or long term, the ability of marine habitats to store carbon is improved by maintaining productive, healthy and biologically diverse marine ecosystems. Scotland’s seas contain a wealth of blue carbon habitats such as saltmarshes, seagrass beds, kelp forests, maerl beds and biogenic reefs, and protecting and enhancing these habitats is essential for healthy seas.

The benefits from protecting blue carbon habitats expands far beyond carbon storage. For example, many of these habitats increase biodiversity, provide vital nursery grounds for juvenile fish and shellfish, improve water quality, increase seafloor integrity, and create the foundations for stable ecosystems.

The current situation

The health of Scotland’s seas is currently in an unfavourable state. Key threats such as physical disturbance from human activities (e.g. fishing) and natural events (e.g. storm surges), increased water turbidity (reduced photosynthesis), coastal erosion/development, and climate change can all disturb, damage and compromise the ability of the sea to capture carbon.

Blue carbon habitats have the potential to make significant contributions to Scotland’s climate change targets, but the extent of this contribution is still unknown. Without improvements in our understanding of distribution, health and potential for enhancement of blue carbon habitats, we limit our ability to identify the most appropriate ways to manage, protect and monitor them.

Our recommendations

To optimise the potential of blue carbon habitats, the Trust recommends the following actions:

  • Increase data collection and improve our knowledge on distribution and health
  • Integrate the value of blue carbon habitats into the process of designating marine protected areas (MPAs)
  • The conservation and enhancement of blue carbon habitats must be incorporated into the management of Scotland’s seas, most notably in Scotland’s National and Regional Marine Plans
  • Allow natural coastal realignment by removing artificial barriers, most notably for restoring and improving saltmarsh habitats

Download our Blue Carbon Briefing

Kelp Forest
Kelp Forest © George Stoyle, SNH


Maerl bed
Maerl bed © Lisa Kamphausen, SNH

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