Salt Marshes and the C02 Climate Change

Analytical Review

  1. Salt marshes across the UK are being lost, what is the Environmental Agency doing to preserve what is left to protect our valuable sink tanks.

Humans have consistently wiped out most of the coastal salt marshes, the ecosystem, and one of our greatest sink tanks and wildlife reserves. This essay is a review where collated information was written in 2009. Climate warming was considered a science issue, and little was known to the public of climate change and global warming.

(Boomberg,2009) points out the negative affects to the ecosystem, but his research shows little of damage to the climate. It could be research data used was not privy to this information. But knowledge of salt marshes acting as carbon sink goes back to the 1960s. This did not stop their destruction anymore than the deforestation of the rain forests .

The problem with losing this natural flood wall and sink tank is, villages and towns all over the UK are dealing with increasing flooding every year. With the climate crisis, they expect this to become an ongoing concern. Since flooding in Somerset 2014, the Environment Agency is taking this seriously. C.Adnitt et al. (2007) write The Environment Agency, through Habitual and Birds Directive and Water Framework Directive, are legal, and duty bound to conserve and enhance Saltmarsh and Mudflats Biodiversity Action Plans.

According to the 2007 Environment Agency manual, the salt marshes and mudflats are been replaced or restored either by ‘biologically equivalent’ or ‘coastal managed realignment’. This will be under management as a protected environmental scheme. You can apply to the agency for a grant for your local conservation area.

Salt marshes are intertidal habitats formed by communities of salt-tolerant … When salt marshes are exposed to erosion or submersion, CO2 is released from these … Salt marshes improve water quality by removing pathogens and pollutants … Coastal and Marine Ecosystems & Global Climate Change: Potential Effects on …

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  • What has the Environment Agency accomplished with regard to restoration of the Saltmarshes.

Many salt marsh’s have been brought back under management preservation, the wildlife is returning, rare birds are nesting, balance is being restored. However, there is yet no specific law and property companies are still able to purchase these precious ecosystems. Owing to the popularity of coastal homes. Coastal housing corporations are worth millions. A law or legislation is needed or these beautiful habitats will continue to perish. Developers can procure these natural ecosystems off  local authorities.  Many of the properties that are built on the coast front are susceptible to flooding as the marshes were natural wave breakers and flood drainers.

The Environmental Agency have produced a booklet on their activities carried out so far. There is also information about their intentional targets of recovering, restoring and overseeing that 40 saltmarshes are replaced throughout the UK a year.

With the sea level’s rising as fast as it is, experts project that there will be scarce coastal front left in many parts of the world.  New developments are exceedingly susceptible to flooding. Because of this that the Environment Agency and the RSPB are looking for more natural flood prevention. Both environment and visual have been considered, the result is to move away from previous man made concrete wave breakers and brick walls by reintroducing the natural way of sustaining and avoiding coastal flooding. 
Certain areas of farm land was once wet lands this was often drained for the purpose of harvesting. The E.A suggest allowing the salt marsh and mudflats to return. This will enable  absorption of high level seawater, storm spray and flooding expected with the climate crisis.

These natural wave breakers that stop the corrosion of the land also support many diverse species within the salt water when the tide is out. Sea grass and other plants support various wildlife indigenous to the area. These became rare or extinct because of sea tide been separated from the marshes they no longer received salt water only rain. Much of their natural habitat died out. The flatness of the land enticed the Victorians to build road tracks for the horse and carriage.   As a consequence digging, draining and separating the marshes from the sea or estuarian caused the same problem.

Railways and roads came, slowly the saltmarshes became smaller and distant from the sea. Engineers across the UK are placing pipes so the tide overflow reaches and replenishes the saltmarshes on the other side of the road. Great lengths are been taken in the restoration of these natural eco warriors of our planet.  


Figures below are from previous forward planning of the plants evolution using photosynthesis it is dated for earlier projects but  it gives the reader an idea of how some of the marshes are managed.

  • How much blue carbon has been released and can we or have we managed to reverse the problem

(Callway J.C, 2005) found in his research that they also store huge amounts of blue carbon as they are sink tanks along with wildlife and important plants. Coastal ecosystem of seagrass, mudflats, and saltmarshes carry a very vital part of our planet’s ecosystem in some ways more than the ecosystem of the rain forest. 95% of carbon seagrass is stored in the marshes but when the marshes are drained by man or natural climate change the carbon gets exposed to the air/oxygen it turns toxic and pollutes the atmosphere the same way permafrost does and the Peatlands throughout the world. All of these are natural sink tanks for carbon and sometimes methane which is more toxic. 

So, these marshes hold a large percentage of the planets C02 and if not protected and the blue carbon will be released back into the atmosphere causing horrendous damage in the way of climate change under global warming. It is imperative these marshes are protected all over the world and they are extremely high in the carbon storage not unlike permafrost.

On a happier note though there has been a massive turn around and countries all over the world are restoring the wetlands in their varied types, this is wonderful news for the planet and the relative environments of the individual countries. Some of the countries have protection laws on their salt marshes and very heavy fines for trespassing or ignoring nesting season.

In 2010 researchers looked at the way carbon mixes with land and air and then the amount of carbon that had been stored in the earth. There was a nearby natural saltmarsh and land. The results turned out to show that the site and the natural marsh had truly little dissimilarities absorbing 0.92 tonnes of carbon per hectare per year.

This is known as coastal managed realignment which is the farmland been turned back into salt marsh naturally, they put a breach in the wall and let the salt marsh soak back in and gain back its terrain slowly thus the land reverts back to how it once was. The EU Habitats Directive obliged the UK to replace salt marshes lost to development with new ‘biologically equivalent’ elsewhere if not possible claim back ( Marshall.T,2013)

“People want quick results, but these things take time,” says lead author Annette Burden, a wetland biogeochemist based at the Centre for Ecology & Hydrology in Bangor. “You can’t expect a piece of land that’s been farmed for a century to turn overnight into something like a saltmarsh that has been there for thousands of years. But the evidence is that this will eventually happen, and this study suggests that the land starts absorbing carbon very quickly after its flood defences are breached.”

Diggers breaching a sea defence

Farmland stolen in the 1800 from salt marsh, salt marsh has taken it back, see the dyke in the background where the water has breached it.

Natural Environment Research Council; Planet Earth

  • We know the saltmarshes are an invaluable asset to our ecosystem but over 6 million was estimated on one project, how can this be justified spending of the taxpayer’s money.

(Valiela et al,2020) write that salt marshes are located between land and the coastal waters for a good reason, they adjoin to all other water ecosystems transferring minerals to deep water. The salt marshes also intercept the surrounding land and draw nutrients and they are also able to support the phytoplankton, Macroalgae and Sea grass by transferring unsalted water and feeding them. It is without a doubt that the saltmarshes are much more than a wildlife sanctuary and sink tank for carbon dioxide.


Adnitt, C. (2007) Environment Agency, Salt Management Manual, R & D Technical Report SC030220, issue 1

Boorman, L.A. (2003). Saltmarsh review: an overview of coastal saltmarshes, their dynamic and sensitivity characteristics for conservation and management. JNCC Report

Callway J.C, (2005) The Challenge of Restoring Functioning Salt Marsh Ecosystems Journal of Coastal Research, SPECIAL ISSUE NO. 40. Coastal Restoration: Where Have We Been, Where Are We Now, and Where Should We Be Going? (WINTER 2005), pp. 24-3

The graham institute blog,(2020) from Climate & Environmental at Imperial state; The Grantham Institute is supported by the Grantham Foundation for the Protection of the Environment

Science Direct; World at Seas: an Environmental Evaluation (Second Edition), 2019′

 Valiela et al, (2020) Role of Salt Marshes as Part of Coastal Landscapes


The Graham Institute blog, (2019)

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