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World Wetlands Day: The hidden potential of tidal landscapes

In a study released just ahead of World Wetlands Day, experts have re-evaluated the vital role of mangroves and salt marshes in carbon sequestration. The researchers determined that these tidal landscapes are far more effective in mitigating climate change than previously recognized. 

According to the study, led by Gloria Reithmaier at the University of Gothenburg, these wetland ecosystems are perhaps twice as effective at capturing carbon as expected. This means that tidal landscapes can provide a much-needed boost in the fight against climate change.

The importance of wetlands

According to the United Nations, even though wetlands cover only around six percent of Earth’s land surface, 40 percent of all plant and animal species live or breed in wetlands. 

“Wetland biodiversity matters for our health, our food supply, for tourism and for jobs. Wetlands are vital for humans, for other ecosystems and for our climate, providing essential ecosystem services, such as water regulation, including flood control and water purification,” said the UN.

“More than a billion people across the world depend on wetlands for their livelihoods – that’s about one in eight people on Earth.”

Carbon storage 

Mangroves and salt marshes, frequently inundated by tides, have long been acknowledged for their ability to store large amounts of carbon dioxide in both their biomass and the muddy soils beneath them. 

Recognizing their value, several governments around the world have initiated blue carbon market initiatives aimed at incentivizing the restoration and preservation of these critical ecosystems, drawing parallels to efforts aimed at protecting rainforests for their carbon storage capabilities.

Unexpected potential 

The latest findings from the University of Gothenburg, however, shine a light on a previously overlooked aspect of these ecosystems’ capacity to combat climate change. 

”We have uncovered additional stored carbon in mangrove forests and salt marshes. Our new findings show that much of the carbon is exported to the ocean bound as bicarbonate as the tide recedes and remains dissolved in the ocean for thousands of years,” said study co-author Gloria Reithmaier.

The bicarbonate plays a crucial role in stabilizing the ocean’s pH levels and potentially reducing ocean acidification, noted Reithmaier. This is particularly important considering the ocean’s role in supporting diverse marine life with the carbonate and bicarbonate ions needed for shell and coral skeleton formation.

Intertidal carbon transport 

To quantify the extent of this carbon sequestration, Reithmaier and her team collaborated with scientists from 12 different countries to analyze intertidal carbon transport in a comprehensive study covering 45 mangrove swamps and 16 salt marshes. 

The research team accounted for the bicarbonate export from the tidal landscapes to the ocean, effectively doubling the previously estimated size of the carbon sink provided by these wetlands. 

Remarkable results

”Our results showed that bicarbonate exports were equal to, or even surpassed, the amount of carbon stored in the soil. Therefore, previous estimates of these blue carbon sources have underestimated the potential of mangroves and salt marshes to mitigate climate change,” said Reithmaier.

”Our results show that blue carbon ecosystems are more effective in mitigating climate change than previously thought. It is now even more important to protect and restore mangrove and salt marsh ecosystems.”

Endangered ecosystems

In the face of escalating environmental crises, wetlands stand out as one of the most critically imperiled habitats on our planet. Recent assessments have highlighted an alarming trend: wetlands are vanishing at a rate thrice that of forests, making them Earth’s most endangered ecosystem. 

Over the past five decades, since 1970, we have witnessed a staggering loss of 35% of the world’s wetlands. This revelation underscores a pressing need for a global reevaluation of how we perceive and manage these vital ecological areas.

World Wetlands Day 

World Wetlands Day is celebrated annually on February 2nd. This day marks the anniversary of the signing of the Convention on Wetlands of International Importance (also known as the Ramsar Convention) in Ramsar, Iran, on February 2, 1971. The purpose of World Wetlands Day is to raise public awareness about the importance and value of wetlands to humanity and the planet.


Each year, World Wetlands Day focuses on a specific theme to highlight particular aspects of wetlands or related issues. This year’s theme is – Wetlands and human well-being.


Wetlands, often undervalued and misunderstood, are in fact indispensable to both the environment and human well-being. They provide a range of ecosystem services including water purification, flood protection, carbon sequestration, and support for biodiversity. 

Furthermore, these ecosystems are a source of livelihood for millions of people worldwide, offering jobs, income, and food security. Despite their importance, wetlands have been subjected to relentless pressures from human activities, leading to their rapid decline and degradation.

Wetland destruction 

The primary drivers behind the loss of wetlands are manifold and complex. Rapid human population growth, unsustainable production and consumption patterns, and technological advancements have exerted significant stress on these ecosystems. Additionally, the adverse impacts of climate change have further exacerbated the vulnerability of wetlands. 

Human-induced activities such as drainage and infilling for agriculture and construction projects, pollution, overfishing, overexploitation of resources, the introduction of invasive species, and the overarching threat of climate change have all contributed to the accelerating rate of wetland destruction.


This decline in wetland areas is not just a loss of natural habitats but also a direct threat to global biodiversity and ecosystem functions. The indicators of negative trends in biodiversity and ecosystem health are stark, with projections showing that these trends are likely to continue unless there is a significant shift in how we address these challenges.


One of the most significant barriers to wetland conservation is the prevailing mindset that views these areas as wastelands rather than critical sources of life and prosperity. This misperception has led to a vicious cycle of wetland loss, threatened livelihoods, and deepening poverty. The challenge lies in changing this mindset to recognize the true value of wetlands. There is an urgent need for governments and communities to shift their priorities and implement policies and practices that protect and restore wetlands.


Education and awareness campaigns can play a crucial role in highlighting the importance of wetlands. Policy reforms that integrate wetland conservation into national and international environmental agendas are imperative. 

Additionally, sustainable management practices that balance economic development with ecological preservation must be adopted to halt and reverse the trend of wetland loss.

Addressing the issue 

The loss of wetlands is a global issue with far-reaching implications for biodiversity, climate stability, and human well-being. Addressing this challenge demands a collective and strategic response that values wetlands for the myriad benefits they provide. 

By promoting a greater appreciation for these vital ecosystems and taking decisive action to protect them, we can ensure that wetlands continue to thrive for generations to come. 

The study is published in the journal Nature Communications

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