Aerial view of pristine wetland ecosystem at sunrise

The Case for Wetlands

Why Are Wetlands
Important?

They filter your water, stop your floods, store your carbon, feed a billion people, and shelter half the world's species. We've destroyed 87% of them — and we're speeding up.

87% lost since 1700

Disappearing 3× faster than forests

If you had to design an ecosystem from scratch that would do the most good for human civilization and all other life on Earth, you would invent the wetland.

No other ecosystem simultaneously purifies drinking water, controls devastating floods, stores the planet's largest carbon reserves, protects coastlines from intensifying storms, provides irreplaceable habitat for half the world's species, and directly feeds over a billion people. And yet, in the span of roughly 300 years — a blink in geological time — we have destroyed 87% of the world's wetlands.

This page presents the scientific case for why wetlands are the most important ecosystem on Earth for human survival, and why their continued destruction is not an environmental story — it's a civilization-level risk that affects every person on the planet, whether they live near a wetland or not.

Six Essential Services

What wetlands do for us — and all life

$47 Trillionannual value of wetland ecosystem services

Water Purification

Wetlands are Earth's most cost-effective water treatment systems. Their soil chemistry and plant roots remove up to 80% of nitrogen and 90% of sediment from water flowing through them — pollutants that would otherwise contaminate drinking water and trigger catastrophic algae blooms in rivers, lakes, and coastal bays. The EPA estimates replacing these natural filtration services with engineered systems would cost $3–75 billion per year in the United States alone. Globally, wetlands provide freshwater purification services worth an estimated $2–3 trillion annually at no cost to governments or consumers.

80%reduction in flood peaks from intact wetland watersheds

Flood Control

Wetlands act as natural sponges that absorb and slowly release floodwater, dramatically reducing the intensity and duration of floods downstream. A single acre of wetland can absorb up to 1.5 million gallons of floodwater. Research across multiple continents shows that watersheds with intact wetland coverage experience 60–80% lower flood peaks than watersheds where wetlands have been drained. The global economic cost of flood damage has increased sixfold since the 1980s — driven almost entirely by wetland destruction combined with climate change. Restoring wetlands is consistently found to be 5–10 times more cost-effective than constructing engineered flood barriers.

2×more carbon stored in peatlands than in all forests combined

Climate Regulation

Wetlands are the single most important terrestrial carbon store on the planet. Peatlands — a waterlogged type of wetland — cover just 3% of Earth's land surface yet hold twice as much carbon as all the world's forests combined, accumulated over thousands of years of slow organic decomposition. Coastal wetlands (mangroves, salt marshes, seagrasses) sequester carbon at rates 10–50 times faster than terrestrial forests per unit area, and store it in deep, permanently waterlogged sediments where it may remain for millennia. When wetlands are drained or burned, this stored carbon is released rapidly — making wetland destruction one of the most intense greenhouse gas emission events possible.

40%of all species depend on wetlands

Biodiversity Sanctuary

Despite covering less than 6% of Earth's land surface, wetlands support over 40% of all species on the planet. This extraordinary concentration of biodiversity arises from the unique conditions wetlands create — shallow water, dense vegetation, nutrient-rich sediments, and the meeting of aquatic and terrestrial environments. Wetlands host over 100,000 freshwater species. More than 3 billion migratory birds rely on wetland stopover sites along their annual migration routes. Many wetland species are endemic — the Barton Springs salamander in Texas, the Bengal tiger in the Sundarbans, the Proboscis monkey in Borneo's mangroves — and will become extinct if their specific wetland habitat is destroyed.

3.5Bpeople in coastal areas protected by wetlands

Coastal Protection

Coastal wetlands — mangroves, salt marshes, and seagrass beds — form a living defense system for low-lying coastlines around the world. Mangrove root networks dissipate up to 70% of incoming wave energy, protecting the 300 million people who live in high coastal flood risk zones. Salt marshes reduce wave heights by 70–90% over a 600-meter distance. Following the 2004 Indian Ocean tsunami, studies found that coastal communities behind intact mangrove forests suffered dramatically lower casualties and property damage than communities where mangroves had been cleared for shrimp farming or tourism infrastructure. As climate change intensifies tropical storms and raises sea levels, the value of this natural coastal armor is increasing exponentially — while we continue to destroy it.

1Bpeople directly dependent on wetlands for food and income

Food & Livelihoods

Wetlands directly support food security and livelihoods for over a billion people worldwide. Over 80% of tropical fish species spend some portion of their life cycle in mangrove and estuarine wetlands — meaning the global fishery, worth over $100 billion annually and feeding 3 billion people, depends fundamentally on wetland health. Freshwater wetlands supply most of the world's rice crop. Coastal wetlands support the productivity of near-shore fisheries that sustain fishing communities from the Philippines to West Africa to the Gulf of Mexico. Communities with the closest relationship to intact wetlands — Indigenous peoples, artisanal fisherfolk, small-scale rice farmers — have the smallest carbon footprints and the most to lose from wetland destruction driven by industrial agriculture and urban development.

The Pace of Destruction