Protect and restore saltmarsh
Cease damage to saltmarsh habitats and establish regeneration targets
Saltmarshes, recognised as one of the most effective habitats for carbon sequestration, should be restored and their extent should be increased.
Salt marshes absorb around 770gCO2e/m2 per year. Due to their relatively limited extent, their overall sequestration in Scotland is only about 0.05MtCO2e/yr; however, this could be increased by improving saltmarsh condition and increasing their extent. Recent research in England concluded that carbon accumulation on restored saltmarsh was initially rapid (average 3.8tCO2e/ha/ yr during the first 20 years), slowing to a steady rate of around 2.4tCO2e/ha/yr thereafter. The resulting increase in carbon stocks gave an estimated total accumulation of 270tCO2e/ha in the century following restoration. This is approximately the same as observations of a natural marsh (250tCO2e/ha).302 The 2010–2012 Saltmarsh Survey found that 67% of saltmarshes are in some way not in good condition. The Habitats Directive and the Water Framework Directive already require that Government avoid deterioration of saltmarshes inside SACs; however, this should now be extended to include all occurrences.
The process of managed realignment of coastal areas, to form new intertidal habitats, is being actively developed elsewhere in the UK, and there are limited, small-scale examples in Scotland (e.g. Nigg Bay). Although there is no substantive programme of expanding inventories of these habitats in the UK solely for the purpose of managing carbon budgets, there are some instances of restoration for biodiversity reasons. It should also be noted that mosaics of habitats that perform together, including not only marshes, seagrass beds and kelp beds, but also tidal flats and even urbanised areas may also yield high carbon sequestration rates.303 Saltmarshes can also be included in national accounting, according to the IPCC 2013 Supplement to the 2006 Guidelines for National Greenhouse Gas Inventories: Wetlands.
For further information:
- IPCC highlights the multiple benefits of restoring wetlands to combat climate change, WWT, April 2022, https://www.wwt.org.uk/news-and-stories/news/ipcc-highlights-the-multiple-benefits-ofrestoring-wetlands-to-combat-climate-change/
- Restoring the Montrose Basin Saltmarsh, Angus Council, January 2023, https://www.angus.gov.uk/ news/restoring_the_montrose_basin_saltmarsh
Effect of restoration on saltmarsh carbon accumulation in Eastern England, A. Burden , A. Garbutt and C. D. Evans. Published:30 January 2019 https://doi.org/10.1098/rsbl.2018.0773
Kuwae T, Hori M (2018) The future of blue carbon: addressing global environmental issues. In: Kuwae T, Hori M (eds) Blue carbon in shallow coastal ecosystems: carbon dynamics, policy, and implementation. Springer, Singapore, pp 347–373