Blue carbon is finally getting the recognition it deserves after a pioneering salt marsh trial on the Steart peninsula in Somerset. Scientists at Manchester Metropolitan University found that the marshes absorbed 19 tonnes of organic carbon a hectare every year. This is the equivalent of eliminating the greenhouse gas emissions of 32,900 cars.
Dr Martin Sullivan, one of the authors of this paper, says: “If you look at the metrics by unit area, then salt marshes will take in carbon much more rapidly than a forest can. They store carbon at a greater density than a forest can.”
Blue carbon refers to marine ecosystems including marshes, wetlands and mangroves that can store thousands of tonnes of carbon. Before 2021 there was limited data on blue carbon which meant that it was often overlooked by policymakers.
“We can’t afford to ignore it. No, we as a society need to look at where we can find all of the opportunities to do this,” says Tim McGrath, Head of Project Development at the Wildfowl & Wetlands Trust (WWT).
The Steart peninsula is close to the Somerset levels where there was severe flooding in 2014. When the project was launched, residents objected to the scheme saying the money would be better spent on flood protection.
“Salt marshes absorb a lot of energy from the waves that cross them. And those waves through the absorption of energy, they reduce their energy…so they have flood defence benefits because those waves are less energetic as they come in contact with other flood defences,” adds McGrath.
The project was led by the Environment Agency and the WWT. They spent £20million creating a 250-hectare salt marsh, moving half a million cubic metres of soil. The area is now home to many species of wildlife including rare birds like black-winged stilts.