Restore Ecosystems - Saltmarshes

Saltmarshes are vital coastal wetlands that play an outsized role in ocean health, acting as blue carbon sinks that capture and store large amounts of carbon in their soils and biomass, helping to mitigate climate change.

They also serve as critical nurseries for fish and invertebrates, supporting coastal livelihoods and food security.

Salt marshes are being lost rapidly due to land reclamation, coastal development, and the pressures of rising seas. Their global extent, carbon sequestration potential, and economic value underline the urgency of their conservationing and restorationing them.

More resources and datasets are available via the Blue Carbon Initiative.

Key Stats

5.45 Million Hectares

Global salt marsh extent.
6–8 Tons CO₂e/hectare/yr

Carbon sequestration rate per hectare per year.
$144 – $3,705 /hectare/year

Total annual global economic value of salt marsh services.
43

Countries with saltmarshes within their EEZs.

Saltmarsh Extent

Map:

Globally, saltmarsh ecosystems have decreased 49.3% between 1900 and 2019.

Saltmarshes Data Score

Data Frequency

20Years
Data Quality

Sufficient - At least 2 data points available for trend analysis AND at least one data point in the last 7 years
Geographic Range

100% of global data avaliable
Global Goal(s)

Global Goal(s)

Data Availability

There is still so much we do not know about our oceans.

Join us in filling critical gaps in ocean data.

Saltmarsh loss is largely driven by coastal development, agricultural expansion, and sea level rise intensified by climate change.

While restoration efforts are underway, many projects remain fragmented, underfunded, or lack long-term monitoring.

Enablers such as the EU Habitats Directive, the US Blue Carbon Initiative, Payment for Ecosystem Services (PES), blue carbon markets, and international funding are creating momentum, yet significant roadblocks persist.

These include inconsistent global mapping, limited integration into coastal planning, and weak local engagement. A key challenge remains whether enough pre-industrial or pre-development data exists to accurately model fully restored saltmarsh ecosystems.

Salt marsh restoration presents an unparalleled opportunity to enhance climate resilience, sequester carbon, restore biodiversity, and protect vulnerable coastlines.

Extent & Change

Explore where saltmarshes are most prevalent and how those habitats are changing.

Extent & EEZ

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There are approximately 54,550 km² of saltmarshes globally — 100% of which lie within national EEZs.

Saltmarsh Gain & Loss

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Globally, saltmarsh ecosystems have gained 1,361 km² and lost 2,675 km² resulting in a net change of -1,314 km² between 2000 and 2019.

Threats and Risks

Salt marsh loss stems from coastal development, land reclamation, and agriculture, now compounded by erosion and accelerating sea level rise. While global data on the exact share of each driver is still limited, sea level rise is the most consistently tracked threat.

Sea Level Rise

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Globally, approximately 11.64% of saltmarshes lie within areas experiencing high sea level rise.

Explore Sea Level Rise

Protection and Restoration

See where salt marshes are safeguarded and how restoration efforts are expanding their coverage.

Protection

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Globally, approximately 22.34% of saltmarshes lie within established protected areas.

Explore Protected Areas

Cumulative Restoration Projects

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Globally, there was an increase of 92 saltmarsh restoration projects between 1972 and 2010.

Restoring salt marshes is one of the most effective nature-based solutions for climate mitigation and coastal resilience. These ecosystems buffer storm surges, store carbon long-term, and support biodiversity, making their restoration essential for both people and nature.

Taking Action

Protect Existing Marshes

Establishing new marine protected areas, inclusive of salt marshes, and strengthening legal protections can safeguard remaining salt marshes.
Restore Hydrology

Reconnecting tidal flows and improving freshwater inflows can revitalize marshes and restore their natural processes.
Manage Sediment

Allowing marshes to migrate inland and restoring sediment flows through reduced damming and dredging helps them thrive.

Address Pollution

Promoting sustainable farming and fishing practices reduces nutrient runoff and other pollutants that harm marshes.
Nature-Based Solutions

Encouraging natural coastal defense systems, like salt marshes, to combat erosion is a cost-effective strategy for climate adaptation.
Mitigate Climate Change

Recognizing salt marshes as key carbon sinks and incorporating them into climate strategies is crucial for long-term preservation.

Marine Spatial Planning

Comprehensive marine and coastal zoning plans that prioritize conservation and restoration efforts can ensure sustainable management of salt marshes.
Engage Communities

Involving local communities and stakeholders ensures the success and sustainability of restoration efforts.
Create Financial Incentives

Developing markets for the ecosystem services provided by salt marshes, such as carbon sequestration and flood protection, can attract investment in marsh restoration.

Research and Monitoring

Ongoing scientific research and long-term monitoring will help track restoration success and inform best practices.
Enhance International Alignment

Linking the benefits of salt marshes to the UN’s Sustainable Development Goals, aligning national and international policies, and fostering international collaboration encourages the protection and recovery of these vital ecosystems.

Case Studies 1

East China Sea
Restoring Salt Marsh Resilience in the Yellow River Delta through Nature-Based Solutions

The Yellow River Delta, home to the iconic “Red Carpet” Suaeda salsa marshes, is one of China’s most ecologically significant coastal wetlands and a critical stopover for migratory birds along the East Asian–Australasian Flyway. Over the past 40 years, these salt marshes have declined by more than 70% due to climate change, invasive species, and hydrological disruption. To reverse this loss, the reserve implemented large-scale Nature-based Solutions (NbS) using microtopography restoration—small terrain adjustments that mimic natural landforms to trap seeds, retain tidal water, and lower soil salinity.

Rather than relying on costly artificial inputs, this NbS approach leverages natural processes to regenerate marsh vegetation, enhance biodiversity, and increase carbon storage. By 2024, over 2,000 hectares had been successfully restored, tripling marsh coverage from its historic low the previous year.

This project demonstrates a low-cost, scalable model for restoring degraded salt marshes using nature as an ally rather than intensive engineering. Restored marshes strengthen coastal resilience, support endangered bird species, improve blue carbon sequestration, and provide a replicable blueprint for climate adaptation in deltas worldwide.

Yellow River Delta National Nature Reserve; Beijing Normal University; UNDP-GEF Flyway Conservation Network; Local ecological restoration teams.
www.undp.org

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View relevant data layers on the globe using the available map toggle in the top right of each card in the left panel.

Note: Loading high-resolution datasets may take up to a minute.

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Restore Ecosystems - Saltmarshes - Ocean Central

Saltmarshes are vital coastal wetlands that play an outsized role in ocean health, acting as blue carbon sinks that capture and store large amounts of carbon in their soils and biomass, helping to mitigate climate change.

Key Stats

Saltmarsh loss is largely driven by coastal development, agricultural expansion, and sea level rise intensified by climate change.

Restoring salt marshes is one of the most effective nature-based solutions for climate mitigation and coastal resilience. These ecosystems buffer storm surges, store carbon long-term, and support biodiversity, making their restoration essential for both people and nature.

Taking Action

Case Studies 1