Why Wetlands Matter: The Freshwater Crisis and the Ocean

Wetlands and their role in the 2026 water crisis

By William Drumm, underwater photographer and ocean ambassador

There is a kind of water most people never picture when they think about the ocean. Not the open blue, not the reef, but the in-between places. The marsh at the edge of a bay. The flooded forest. The slow shallow stretch where a river loses its hurry before it reaches the sea. These are wetlands, and they may be doing more to keep the ocean alive than anything else on land.

I have spent most of my life photographing water in its many forms, fresh and salt, still and moving. The lesson that keeps repeating is that none of it is separate. The tadpoles in a remote mountain lake, the manatees in a Florida spring, the reef I will dive next month: it is all one system, and wetlands are the tissue that holds it together.

This is Part 2 of the Ocean Worth Saving series, and it arrives at a hard moment for freshwater. In January 2026 the United Nations used a word it had never used before to describe the state of the world’s water systems. Not stressed. Not in crisis. Bankrupt. To understand why that matters for the ocean, and why wetlands sit at the center of the story, it helps to start with what wetlands actually are.

Quick Facts: The Global Water Crisis in 2026

From the United Nations 2026 Global Water Bankruptcy report.

• Population in water-insecure or critically water-insecure countries: 75%
• People facing severe water scarcity at least one month a year: 4 billion
• People lacking safely managed drinking water: 1 in 4
• Large lakes that have lost water since the early 1990s: more than half
• Glacier mass lost since 1970: more than 30%
• Natural wetlands destroyed in the past five decades: about 410 million hectares (roughly the size of the European Union)
• Freshwater lost each year: about 324 billion cubic meters (enough to meet the needs of 280 million people)
• Water US AI servers could add per year by 2030: 200 to 300 billion gallons
• People the Colorado River supplies across seven US states and Mexico: about 40 million
• Date the UN formally declared global water bankruptcy: January 20, 2026
• Freshwater Challenge global goal by 2030: restore 300,000 km of rivers and 350 million hectares of wetlands

What Are Wetlands and Why Do They Matter?

Before we talk about what we have lost, it is worth being clear about what wetlands are and why they matter so much.

Wetlands are areas where water covers the soil, or sits at or near the surface, for varying periods of the year. The defining feature is not how much water but the steady presence of it, shaping the soil and the species that live there. Wetlands are among the most biologically productive ecosystems on Earth, often rivaling tropical rainforests and coral reefs in the sheer density of life they hold.

Types of Wetlands

There are five main categories, each with its own character.

• Marshes. Treeless wetlands dominated by grasses, reeds, and sedges, found inland as freshwater marshes and along coasts as salt marshes. Salt marshes in particular are critical nurseries for ocean fisheries.
• Swamps. Wetlands dominated by trees and woody plants, from cypress swamps in the southeastern US to mangrove swamps along tropical coastlines. Mangroves are the connective tissue between freshwater swamps and coral reefs.
• Bogs. Spongy, acidic, peat-forming wetlands carpeted in sphagnum moss. Peat bogs are remarkable carbon stores, holding more carbon per acre than rainforest.
• Fens. Like bogs, but fed by mineral-rich groundwater, which supports more diverse plant life. Often found in glaciated landscapes.
• Estuaries and coastal wetlands. Where freshwater rivers meet the ocean. Among the most productive habitats on Earth, with roughly 75% of commercially valuable ocean fish species spending part of their life cycle in coastal wetlands.

What Wetlands Do

Wetlands are the connective tissue between freshwater and ocean systems, and they do several jobs at once.

• Filter pollution before it reaches the coast, stripping out sediment, nutrients, and many contaminants.
• Buffer flood surges that would otherwise overwhelm reefs and coastal communities.
• Store carbon, with coastal wetlands sequestering it at up to 50 times the rate of tropical forest per unit area.
• Provide nursery habitat for fish that spend their adult lives in the open ocean.
• Regulate temperature and humidity in the surrounding landscape.
• Hold water during drought and release it slowly through dry seasons, stabilizing freshwater supplies.

When we drain a wetland to build a farm or a road, we are not just removing a habitat. We are removing a water treatment plant, a flood barrier, a carbon sink, and a marine nursery, all at once.

Wildlife in Wetlands

A healthy wetland is one of the most alive places on Earth. The cast depends on the ecosystem type, but the broad strokes hold.

Wetland birds

Wetlands are critical for migratory and resident birds: wading birds (herons, egrets, ibises, spoonbills), waterfowl (ducks, geese, swans), shorebirds, rails, kingfishers, and many songbirds. More than half of North American bird species use wetlands at some point in their lives, and the loss of wetland habitat is one of the leading drivers of bird population decline.

Wetland animals

Beyond birds, wetlands hold amphibians (frogs, toads, salamanders, the canaries of freshwater health), reptiles (turtles, alligators, crocodiles, snakes), juvenile fish using the shallows as nurseries, and mammals (otters, muskrats, beavers, and depending on region, raccoons, mink, even moose). The manatees I have photographed in Crystal River live in spring-fed wetland. The crocodiles I photographed in Banco Chinchorro are part of a complex mangrove system.

Wetland plants

Cattails, sedges, bulrushes, water lilies, mangroves, cypress, sphagnum moss, pickerelweed, and arrowhead, each playing a role in filtration, soil stability, and habitat structure.

Slowing down at the edge of a marsh or estuary, even for ten minutes, usually rewards you with sightings most people walk right past.

The Freshwater Crisis: What Water Bankruptcy Means

This brings us back to the word the UN used in January 2026. The report, from the UN University Institute for Water, Environment and Health, concluded that humanity has moved past temporary shortage into something more permanent. Many river basins and aquifers, it found, have entered a post-crisis condition in which the old baselines are no longer reachable without transformative change.

Water bankruptcy is a chronic condition. It develops when a place uses more water than nature can reliably replace, and when the natural assets that store and filter that water (aquifers, wetlands, glaciers) are damaged beyond easy repair. In financial terms, the world has been spending more than it earns for decades. Now the account is empty and the collateral has been sold.

The figures behind the declaration are stark. Three-quarters of the global population lives in water-insecure or critically water-insecure countries. Four billion people face severe water scarcity for at least one month a year. More than half of the world’s large lakes have lost water since the early 1990s, over 30% of glacier mass has vanished since 1970, and around 410 million hectares of wetlands, nearly the area of the European Union, have been destroyed in the past five decades. The world is losing roughly 324 billion cubic meters of freshwater a year, enough to meet the needs of 280 million people.

Kaveh Madani, the report’s lead author and Director of UNU-INWEH, was careful to frame this not as a death sentence but as the first honest admission that the old approach has failed and a new one is required.

How Freshwater Connects to the Ocean

It is easy to think of freshwater and the ocean as two separate worlds. They are not. They are two ends of the same plumbing.

 Every river carries the land’s runoff to the coast. When that runoff is clean, it delivers the nutrients and sediment that build deltas and feed estuaries. When it is loaded with fertilizer, plastic, and sewage, it delivers those too, straight into the nearshore waters where most ocean life begins. Drain the wetlands in between and you remove the filter that would have caught much of it. Pump out the aquifers and the coastal land begins to sink, letting saltwater push inland into systems that fish and birds depend on.

Coral reefs, seagrass beds, and mangroves are all shaped by what happens upstream. A reef below a healthy watershed has a fighting chance. A reef below a degraded one is fighting with one fin tied behind it. The freshwater crisis and the ocean crisis are the same crisis wearing different clothes.

How Water Pollution Affects Marine Life

Water pollution is not one thing. It is dozens of distinct kinds of harm reaching the sea through different doors. Here is what is actually happening.

Agricultural Runoff

Fertilizers and pesticides wash off farm fields into rivers and out to the coast. The result is algal blooms that strip the oxygen marine life needs, creating dead zones, plus contaminated shellfish and disrupted reef chemistry. The Gulf of Mexico dead zone, fed by Mississippi River runoff, can cover more than 6,000 square miles in summer, a stretch of ocean essentially uninhabitable to most fish.

Plastic Pollution

Roughly 8 to 12 million metric tons of plastic enter the ocean every year. Microplastics now turn up everywhere, including the deepest trenches. Animals from plankton to whales ingest it, often fatally, and the plastic leaches chemicals that disrupt marine endocrine systems.

Industrial Chemicals and Heavy Metals

Mercury from coal plants accumulates in fish tissue. Persistent pollutants like PCBs and DDT, banned in many countries, still circulate decades later. PFAS, the so-called forever chemicals from firefighting foam and non-stick coatings, are now detectable in Arctic seals.

Sewage and Pathogens

Untreated or poorly treated sewage carries pathogens, pharmaceuticals, and excess nutrients into coastal water. Reefs near population centers are hit hardest, and sewage exposure correlates strongly with coral disease outbreaks.

Acidification

The ocean absorbs about 30% of human carbon dioxide emissions. As that CO2 dissolves it forms carbonic acid, and ocean pH has dropped 0.1 unit since pre-industrial times, a 30% rise in acidity. The cost is paid by anything that builds a shell or a skeleton: mollusks, sea urchins, and coral.

Oil Spills

Headline disasters like Deepwater Horizon and Exxon Valdez cause acute death and linger in sediment for decades. But chronic, small-scale oil pollution from shipping and runoff adds up to far more total volume than the famous spills.

What This Looks Like Underwater

I have photographed reefs that show none of this, where the water is clear, the coral bright, the fish abundant. I have also photographed reefs where the algae are winning, the coral looks stressed, and you can taste the pollution at the surface. The contrast between the two, sometimes within the same country, sometimes within the same week of travel, is a lot of what makes this work feel urgent.

What Individuals Can Do

• Reduce single-use plastic. The most direct individual lever.
• Use phosphate-free detergents and avoid fertilizing lawns near waterways.
• Dispose of medications, motor oil, and household chemicals properly, never down the drain.
• Support agricultural policies and regenerative practices that reduce runoff.
• Choose seafood certified against pollution and bycatch impacts.
• Vote and advocate for funding of municipal water treatment.

AI, Data Centers, and a New Strain on Freshwater

There is a new pressure on freshwater that barely existed at scale a decade ago, and it is growing faster than almost anything else in this story. Artificial intelligence runs on data centers, and data centers run hot. The most common way to keep thousands of densely packed processors from overheating is to evaporate water, and AI workloads throw off far more heat than the computing that came before them.

The numbers are sobering. One analysis of Texas alone found data centers there on track to use roughly 49 billion gallons of water in 2025, and as much as 399 billion gallons by 2030, enough to draw the largest reservoir in the country, Lake Mead, down by more than sixteen feet in a single year (Houston Advanced Research Center and the University of Houston, via the Lincoln Institute of Land Policy). Across the United States, AI servers are projected to add somewhere between 200 and 300 billion gallons of annual water demand by 2030. Researchers at the University of California, Riverside estimate that by 2027 global AI could drive water withdrawals of 1.1 to 1.7 trillion gallons a year, several times the total annual water use of a midsized country.

The problem is not only the volume. It is the location. Google reported using more than five billion gallons across its data centers in 2023, with roughly a third drawn from watersheds already under medium or high water stress. A data center built in a dry region does not just use water, it competes for it, against farms, towns, and the same rivers and wetlands this article is about. Training a single large model has been estimated to evaporate hundreds of thousands of liters of clean freshwater before it ever answers a question.

Here is the turn, because none of this is fixed in stone and the engineering response is moving fast. Closed-loop and zero-water cooling systems, which recirculate the same coolant instead of evaporating fresh supply, are becoming a genuine industry direction: one major operator’s newer closed-loop design is expected to cut water use by more than 125 million liters per facility each year. Immersion cooling, where servers sit in a heat-conducting fluid, and smarter siting of data centers in water-secure regions can cut the combined footprint substantially.

And AI itself is increasingly a tool on the other side of the ledger. Utilities and conservation groups now use machine learning to find pipe leaks, model droughts, optimize reservoir releases, and monitor wetland and watershed health from satellite imagery at a scale no human team could match. The honest summary is that AI is both a fast-rising draw on freshwater and, potentially, one of the better instruments we have for managing what is left. Which one it becomes depends on decisions being made right now about how data centers are cooled and where they are built.

The Colorado River: A Watershed Under Pressure

I live in Denver, which means I live near the top of one of the most contested watersheds in the world.

A watershed, also called a drainage basin, is all the land where rain and snowmelt collect and drain toward a common outlet, a river, a lake, or the sea. Everyone lives in one. Mine drains, in part, toward the Colorado River, which begins as snowmelt in the Rocky Mountains not far from my home and runs more than a thousand miles toward the Gulf of California. Much of Denver’s tap water is in fact Colorado River water, carried across the Continental Divide through tunnels bored a century ago. Most people on the Front Range never realize they are drinking from the same river that fills Lake Powell and Lake Mead.

That river is in trouble. The Colorado supplies about 40 million people, some 30 tribal nations, and more than five million acres of farmland across seven US states and two states in Mexico. It has been overdrawn for a hundred years. The 1922 compact that still divides its water was negotiated during an unusually wet stretch and promised out more water than the river actually carries in a normal year, let alone after twenty-five years of drought sharpened by a warming climate. Lake Mead and Lake Powell, the two largest reservoirs in the country, now sit near their lowest levels since they were filled, the pale bathtub rings on their canyon walls marking how far the water has dropped.

The reckoning is happening now. The operating rules that govern how water moves between Powell and Mead expire at the end of 2026, and the seven states have spent more than a year struggling to agree on what replaces them. They blew past a federal deadline, drew warnings of looming litigation, and heard one senior water manager say plainly that the original compact could be breached in 2026 and almost certainly in 2027 (post-2026 negotiations; US Bureau of Reclamation). The cuts are already real: Arizona has been losing roughly 18% of its allocation, Mexico 5%, Nevada 7%.

And here is the part that ties back to the ocean. The Colorado River used to reach the sea. Its delta in the Gulf of California was once a vast wetland, a green braid of marsh and lagoon where the river met saltwater and fed an entire ecosystem of fish and birds. For most of the past several decades the river has been so fully diverted that it rarely arrives at the ocean at all, and the delta has largely dried. It is the clearest illustration of the thread running through this whole piece: take too much freshwater upstream, drain the wetlands in between, and the ocean feels it at the river’s mouth.

The Restoration Case

Here is where the story turns, because bankruptcy is not the end of action. It is the start of a structured recovery: stop the bleeding, protect what is essential, restructure the unsustainable claims, and invest in rebuilding. And the science on wetland restoration is increasingly on our side.

A 2025 study found that restoring floodplain wetlands cut carbon emissions by 39% and brought back key ecosystem functions within a single year, with soil moisture rising 55% even after the sites had previously dried out. The Freshwater Challenge, a country-led global initiative, aims to restore 300,000 km of degraded rivers and 350 million hectares of degraded wetlands by 2030, and more than 50 countries have already joined.

Closer to home, a major restoration on California’s Prairie Creek finished construction in early 2026. The project removed more than 20 acres of asphalt from a former mill site, created two new backwater ponds and over 20 acres of wetlands, and planted 212,000 native plants to stabilize the soil and rebuild habitat for salmon and steelhead. These are not small wins. They are proof that ecosystems respond when we give them the chance.

What This Has to Do With Diving

I have spent most of my adult life underwater. I have seen what healthy water looks like, the clarity, the color, the sheer amount of life it holds, and I have seen what happens when it degrades.

The northwestern toad tadpoles I photographed in a remote British Columbia lake, thick enough in the shallows to darken the water. The crocodiles in Banco Chinchorro moving through water so clear you could count their scales. The manatees in Crystal River hovering in springwater that filtered slowly through limestone over decades. Whether I am photographing Billie Eilish underwater for the Hit Me Hard and Soft album cover or a toad the size of a fingernail in a mountain lake, the same truth holds: the water in front of the lens is connected to every other body of water on Earth.

All of it is connected. All of it is water.

The UN’s declaration is not a reason to stop caring. It is a reason to care more precisely. Protect the wetlands. Restore the rivers. Stop treating freshwater as if it were infinite. And remember that every drop that falls on land eventually finds its way to the sea. The ocean needs healthy freshwater to survive, and so do we.

The Bottom Line

Declaring bankruptcy is not giving up. By the account of the UN’s own lead scientist, it is the first honest admission that the old approach has failed and a new one is needed.

Restoration works. Wetlands recover within a year when we let them. Rivers heal when we remove what is blocking them. Fish return when the water runs clean. The question was never whether it is possible. The question is whether we decide it matters.

It does.

Frequently Asked Questions about wetlands

What is a wetland?

A wetland is an area where water covers the soil, or sits at or near the surface, for at least part of the year. That steady presence of water shapes the soil and the species that live there. Wetlands are among the most biologically productive ecosystems on Earth, comparable to rainforests and coral reefs. The five main types are marshes, swamps, bogs, fens, and estuaries.

Why are wetlands important?

Wetlands do several jobs at once. They filter pollution before it reaches the coast, buffer floods, store carbon (coastal wetlands at up to 50 times the rate of tropical forest per unit area), provide nursery habitat for ocean fish, regulate local temperature and humidity, and hold water through drought. In effect, a single wetland is a water treatment plant, a flood barrier, a carbon sink, and a marine nursery at the same time.

What animals live in wetlands?

Wetlands support birds (more than half of North American bird species use them at some point in their lives), amphibians like frogs, toads, and salamanders, reptiles such as turtles, alligators, and crocodiles, fish that use wetlands as nurseries, and mammals including otters, beavers, muskrats, and manatees. Wading birds such as herons, egrets, ibises, and spoonbills are especially associated with wetlands.

What is a watershed?

A watershed, also called a drainage basin, is all the land where rain and snowmelt collect and drain toward a common outlet such as a river, a lake, or the ocean. Everyone lives in a watershed. What happens on that land, whether farming, paving, pollution, or restoration, eventually reaches the water it drains into, which is why watershed health and ocean health are tied together.

How much wetland has been lost worldwide?

About 410 million hectares of natural wetlands have been destroyed over the past five decades, an area roughly the size of the European Union. Loss continues today through drainage for agriculture, development, and the effects of climate change.

Can wetlands be restored?

Yes, and often quickly. Research on floodplain wetland restoration has found carbon emission cuts of around 39% and the return of key ecosystem functions within a single year, with soil moisture rising about 55% even after sites had dried out. The Freshwater Challenge aims to restore 300,000 km of rivers and 350 million hectares of wetlands by 2030.

How does water pollution affect marine life?

Through several pathways: agricultural runoff feeds algal blooms and dead zones, plastic is ingested by animals from plankton to whales, industrial metals accumulate in fish tissue, sewage spreads pathogens and excess nutrients, ocean acidification makes shells and coral skeletons harder to build, and oil spills cause harm that lingers in sediment for decades.

How does AI use water?

AI runs on data centers, and data centers run hot. Many cool their servers by evaporating freshwater, and AI workloads generate far more heat than older computing. Estimates suggest US AI servers could add 200 to 300 billion gallons of annual water demand by 2030, and much of that draws on regions already under water stress. Newer closed-loop and zero-water cooling designs can reduce this dramatically.

How does freshwater connect to ocean health?

Everything that happens to freshwater eventually reaches the sea. Polluted rivers carry runoff, plastic, and sediment to the coast. Drained wetlands remove the natural filters that keep nearshore water clean. Depleted aquifers let coastal land sink and saltwater push inland. The freshwater crisis and the ocean crisis are the same crisis wearing different clothes.

Why is the Colorado River in trouble?

The Colorado River supplies about 40 million people and irrigates millions of acres across seven US states and Mexico, but it has been overdrawn for a century. The 1922 compact that divides its water was written during an unusually wet stretch and assumed more flow than the river actually carries. After roughly 25 years of drought, Lake Mead and Lake Powell sit near historic lows, and the rules that govern them expire at the end of 2026.

What is water bankruptcy?

Water bankruptcy is a chronic condition in which a region uses more water than nature can replace and the natural systems that store and filter water (aquifers, wetlands, and glaciers) are damaged beyond easy repair. The UN University Institute for Water, Environment and Health introduced the term in a January 2026 report to signal that many basins have moved past crisis into a post-crisis state.

What is the Freshwater Challenge?

The Freshwater Challenge is a country-led initiative launched at the 2023 UN Water Conference, with a goal of restoring 300,000 km of degraded rivers and 350 million hectares of degraded wetlands by 2030. More than 50 countries have joined, making it the largest freshwater restoration effort in history.

How can individuals help with water conservation?

Cut single-use plastic, use phosphate-free detergents, keep lawn fertilizer away from waterways, dispose of medications and chemicals properly, support farming and seafood practices that reduce runoff, advocate for water treatment funding, and donate to wetland groups such as Wetlands International or Ducks Unlimited.

Take Action

If this piece was useful:

• Read Part 1 of the Ocean Worth Saving series, “Is the Ocean Going to Be Okay? What 2025’s Data Actually Shows“
• Read Part 3, “Sharks Are in Trouble. Conservation Is Also Working” (coming soon).
• See my photography from freshwater and ocean systems on my underwater blog.
• Support a freshwater or wetland organization: Wetlands International, Ducks Unlimited, The Freshwater Trust, or your local land trust or watershed alliance.
• Sign up for my newsletter. 
• Share this piece. The freshwater crisis and the ocean crisis are the same crisis wearing different clothes.

Sources and Further Reading

• Madani, K. (2026). Global Water Bankruptcy: Living Beyond Our Hydrological Means in the Post-Crisis Era. UN University Institute for Water, Environment and Health (UNU-INWEH). DOI: 10.53328/INR26KAM001
• Ramsar Convention on Wetlands: Global Wetland Outlook, 2025 edition
• UN-Water: SDG 6 Synthesis Report on Water and Sanitation
• Journal of Environmental Management, July 2025: floodplain wetland restoration, carbon and ecosystem-function findings
• Wetlands International: 2025 Year in Review
• California Trout / Prairie Creek Restoration Project reports, January 2026
• The Freshwater Challenge: country-led initiative on river and wetland restoration
• US Environmental Protection Agency: National Aquatic Resource Surveys
• NOAA: National Coastal Condition Assessment
• Cornell Lab of Ornithology: wetland bird habitat research
• Lincoln Institute of Land Policy (2026), citing Houston Advanced Research Center and the University of Houston: data center water use in Texas
• University of California, Riverside: projections of AI-driven global water withdrawals
• US Bureau of Reclamation: Colorado River post-2026 operations and reservoir projections