A report from the WWF (World Wide Fund for Nature) says the UK’s saltmarshes are vital “sinks,” reducing carbon from the atmosphere. Though much of the saltmarshes has vanished from the UK, a significant role has been played by them in the fight against climate change. Once, the saltmarshes held referable portions of land but have decayed over the decades.
The report by WWF contains comprehensive inquiry and research explaining how the saltmarshes absorb CO₂ from the atmosphere and store it. The WWF attributed the UK’s saltmarshes as “unsung heroes” for their role in mitigating climate change. It is urging the UK government to restore the saltmarshes back to good health through official acknowledgment, which is expected to strengthen efforts to restore and safeguard additional saltmarsh habitats across the UK.
Partnering with experts from the UK Centre for Ecology & Hydrology, the World Wide Fund for Nature (WWF) deployed solar-powered instruments to monitor greenhouse gases at Hesketh Out Marsh—a rehabilitated saltmarsh in North-West England, overseen by the Royal Society for the Protection of Birds (RSPB).
Throughout the year-long study, researchers tracked air movement across the marsh and found that, during summer, the plants absorbed more carbon dioxide than they released in the colder months.
These insights expand on earlier research that examined carbon storage within the marsh’s muddy layers.
To support the equipment in this tidal environment, the team erected a robust tower standing 2.5 metres high, built from scaffolding poles. Its height ensured the monitoring tools remained protected from seawater and drifting debris during floods.
Led by WWF ocean conservation specialist Tom Brook, we navigated through dense, thigh-high grasses to reach the heart of the experimental site.
At low tide, the sea disappears from view beyond the vast grassland, leaving behind scattered driftwood, some plastic debris, and even a small, overturned boat nearby.
“The plants here grow so rapidly during spring and summer that they almost overlap—forming layers that eventually break down,” explained Tom Brook. “This natural process traps carbon within the soil. While we often learn about trees absorbing carbon and storing it in their trunks, in saltmarshes, this function is carried out by the mud.”
“In that sense, the mud found in saltmarshes is just as crucial for climate mitigation as forests.”
WWF has released the first year of findings in a report titled The Importance of UK Saltmarshes. Notably, the report was co-published with an insurance company interested in assessing how saltmarshes contribute to protecting coastal communities from flooding.
Since 1860, the UK has lost approximately 85% of its saltmarshes. Once considered unproductive land, many of these areas were drained and repurposed for agriculture.
Hesketh Out Marsh has undergone successful restoration after being acquired by the wildlife charity RSPB and reconnected to the tidal flow. Now, in late spring, the area is alive with bird activity. Numerous species—including avocets, oystercatchers, and black-tailed godwits—can be seen foraging in the mud and nesting on the land nestled between lagoons and tidal channels.
The researchers hope that their findings will strengthen the argument for the restoration and protection of more of these vital muddy buffer zones that lie between the land and the sea.
