The continued loss of saltmarshes is threatening international progress on climate goals, a new report launched this week at the United Nations Ocean Conference has warned, revealing that the extent of the area these vital tidal wetlands once covered has been depleted by more than half in recent decades.

The report – published by WWF and Sky in collaboration with the UK Centre for Ecology and Hydrology and Blue Marine Foundation – warns that areas that act as crucial carbon sinks are rapidly being turned into carbon sources contributing to the warming climate crisis.

On top of this, with the rapid depletion of their area coverage, coastal communities are fast losing the natural protections from flooding events that they once provided.

Between 2000 and 2019 alone, the world saw a net saltmarsh loss of 1,435 km2 – an area twice the size of Singapore. This continues to disappear at a rate of 0.28% per year, which is faster than reported for the other blue carbon ecosystems, such as mangroves and peatlands, and three times faster than forests.

The report shines a light on what we have lost and continue to lose, where the biggest opportunities lie and what needs to change.

It highlights that up to 2 million hectares (20,000 km2) of saltmarsh could be restored globally, unlocking their vast potential as flood defences and powerful carbon sinks – making them one of the most scalable nature-based solutions to the climate crisis available. 

Tom Brook, oceans specialist at WWF-UK, said: “Saltmarshes are doing a lot of the heavy lifting for the climate with little recognition. They’ve been reduced to a fraction of their former range – but with the right support, we can turn the tide, and we are now seeing a surge in ambition to protect and restore these coastal habitats.

“These efforts are not just symbolic; they are starting to add up and momentum is building. The next chapter for saltmarshes could be one of recovery and renewal – delivering carbon storage, storm protection, biodiversity and community resilience, all at once.”

Saltmarsh decline over the last century has been shaped by human influence. As coastlines were transformed to feed, house and connect growing populations, saltmarshes were among the first casualties. They were drained, diked and reclaimed – turned into farmland, shrimp ponds, ports or cities.

However, with the right support, these saltmarshes could be recovered. In parts of the United States, northwest Europe, China, and Australia, saltmarshes have shown signs of recovery. 

Fiona Ball, Group Director Bigger Picture and Sustainability at Sky, said: “Our partnership with WWF continues to play an important part in our work to protect and restore nature and biodiversity in the UK, which we know are critical in tackling climate change and supporting a sustainable, low carbon world. 

“Given the potential of saltmarshes to sequester carbon and serve as natural flood defences, and the role of the UK as home to one of the largest saltmarshes in Europe, we’re delighted to be helping WWF raise awareness for saltmarsh conservation.”

The report has recommended that governments now elevate saltmarshes in their national climate and nature plans and invest in their recovery. It also acts as a platform for raising the visibility of saltmarshes when it comes to conversations around climate change and calls on world leaders to integrate saltmarshes into their global goals for the ocean.  

Saltmarshes are natural climate buffers. They absorb wave energy, reduce erosion and store carbon at rates faster than forests, making them vital allies in the race to a net-zero world.

They are also biodiversity strongholds, home to rare and migratory species, nurseries for fish and vital stopovers for birds, linking land, sea and sky in webs of life that few other ecosystems can rival.

Maddie Millington-Drake, Senior Climate Project Manager at the Blue Marine Foundation said: “Saltmarshes have been overlooked for far too long, despite being among the most effective ecosystems for locking away carbon, buffering coastlines, and supporting biodiversity. This report shows we’re losing them faster than forests, and that loss comes at a high cost. But it also makes clear that recovery is within reach.

With coordinated global action, saltmarshes could be one of this decade’s leading nature-based success stories. Blue Marine Foundation is proud to support this report and the wider effort to turn the tide. Protecting these habitats isn’t just an environmental responsibility, it’s a smart, scalable response to the climate and coastal resilience crises we face.”

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