THE SKY SHIMMERS A BRIGHT blue. The woods and thickets, a dappled green. The beaches, a blinding white. Splashes of pink, on the wings of roseate spoonbills and atop blooming ipês trees. On the face of it, much of the beauty of the Pantanal — the world’s largest tropical wetland, located in the heart of South America — appears unchanged. But Enilza da Silva knows it is not so. The 51-year-old fisherwoman recognizes signs in the landscape that indicate all is not right. There are signs, she says, that this rich, biodiverse land, where she was born and raised, and her way of life are under threat.

“The river has changed a lot in recent years. It is silted; it has less water, even when it isn’t the dry season,” she laments. And the nearby woods, which had never witnessed intense fire before, burned to ashes in 2020, leaving behind the corpses of trees and the silence of animals that didn’t return.

“The Pantanal’s biggest threat lies outside its borders.”

“After the fire, many animals disappeared. There were so many animals here. There were jaguars, tapirs, curassows, and monkeys. Now they are rare,” she says. Dona Nilza, as she is locally known, still weeps when she remembers the pained moans of jaguars and the desperate bawls of monkeys as they were overtaken by the conflagration that, according to Brazilian wildlife scientists, killed at least 17 million vertebrates across the Pantanal. “We tried to save the animals, built firebreaks to contain the flames, gave them water and food, but it wasn’t enough,” she says.

Dona Nilza lives along one of the countless curves of the Paraguay River in Brazil’s Mato Grosso state, where the savanna vegetation of the surrounding Cerrado plateau dips down to meet the marsh plants of the Pantanal’s wetlands. Her home, on the upper reaches of this gently sloping river basin, has mosquito screens for walls. Those pesky blood-suckers are the only “wildlife” she and her family truly fear. Her backyard is filled with plants that are common to several of Brazil’s other terrestrial biomes — water lilies, water hyacinths, yellow cambarás (lantana) that are typical of the Amazon that lies up north, pink ipês that can be seen in the Atlantic Forest located to its southeast, acuris palms and paratudos or the yellow ipês that are common in the Cerrado highlands that embrace the Pantanal on three sides. The presence of plant communities typical to other biomes underscores the Pantanal’s connection to landscapes beyond its boundaries. It is a connection that has kept it alive and thriving for ages, but that is now, in combination with various other factors such as land use changes and climate disruption, becoming a key cause of its undoing.

As Gustavo Figuerôa, communications director of the Upper Paraguay Basin Socio-Environmental Institute SOS Pantanal, says: “The Pantanal’s biggest threat lies outside its borders.”

THE KINGDOM OF WATER, as the Pantanal is often called, is a vast, internal river delta comprising a network of tropical swamps, forests, and flooded savannas. More than 10 times the size of Florida’s Everglades wetlands, it extends some 171,000 square kilometers across south-central Brazil and neighboring Bolivia and Paraguay. Most of it — about 151,000 square kilometers — lies in Brazil’s Mato Grosso and Mato Grosso do Sul states. A UNESCO biosphere reserve that is also listed as a National Heritage Site in Brazil’s 1988 constitution, it is the smallest of the country’s six terrestrial biomes, occupying only 1.8 percent of its territory, and not quite as globally famous as the Amazon basin. But this floodplain is of great ecological importance thanks to its unique hydrological cycle.

During the rainy season — which can last four to six months from October to March — sediment and nutrient-rich floodwaters from its primary waterway, the Paraguay River, and its tributaries flow down from the surrounding Cerrado plateau and submerge 80 percent of the Pantanal, turning it into a giant reservoir. Over the next several months, usually from April through September, the water gradually drains away, leaving behind pools that teem with wildlife and continue to provide precious freshwater through the dry months.

This “flood pulse” helps support an incredible variety of life in the Pantanal — the region is home to more than 4,700 plant and animal species, including the world’s largest population of jaguars, as well as caimans, giant river otters, giant armadillos, endangered maned wolves, marsh deer, hyacinth macaws, toucans, and jabiru storks — and also offers natural flood protection to millions of South Americans living downstream.

The wetlands support the livelihoods of around 1.5 million people living in the region and in downstream towns, villages, and Indigenous communities across Brazil, Bolivia, and Paraguay. Many of them, like Dona Nilza, still live subsistence lifestyles, fishing and farming, selling what they catch or grow, and eating the rest. Others rely on the region’s thriving sport fishing and jaguar tourism industry. According to one study, jaguar tourism brings in nearly $7 million annually in Northern Pantanal. Some engage in traditional cattle ranching, which has been a major economic activity here since European colonization and has had a relatively low impact on the ecosystem. (There are currently about 3,000 ranches in the Brazilian portion of the Pantanal).

More than 90 percent of the land here is privately owned, and only 2 percent of it — areas encompassing the Taiamã Ecological Reserve and the Pantanal Matogrossense National Park — is under government protection. Despite this, until recently, the Pantanal was relatively intact, thanks to its remoteness and the waterlogging that made large swathes of it inhospitable for most of the year.But over the past few decades, the gradual expansion of industrial-scale farms and ranches and climatic factors, such as lower precipitation and searing droughts, have begun to have a dramatic impact on this region. And now several upstream infrastructure projects on the Paraguay River and its tributaries — including a series of small hydroelectric dams, as well as a waterway project aimed at turning the river into a shipping channel for large barges carrying soybeans and other commodities southwards toward Argentina for export — threaten to change the Pantanal irrevocably.

OMENS THAT SAVVY FISHERFOLK such as Dona Nilza perceive in nature about the state of the region are corroborated by hard data collected by scientists that allow us to measure just how big the observed changes are, to identify their causes, and to propose solutions.

Analyses from MapBiomas, a collaborative network of nonprofits, universities, and startups that tracks land transformations in Brazil, show that the Pantanal’s water surface has shrunk by 29 percent in the past three decades, largely as a result of the drop in water flows from the Cerrado highlands and the Amazon rainforest. In fact, research from a team led by Solange Ikeda-Castrillon, a biologist at Mato Grosso State University’s Pantanal’s Limnology, Biodiversity and Ethnobiology Center, shows that Northern Pantanal lost 16 percent of its water mass in just the last 10 years. The flooding period also decreased from six to three months and is now concentrated mostly in the months of December, January, and February. The nutrient flow that feeds the Pantanal depends on this flooding, explains Eduardo Reis Rosa, mapping coordinator at MapBiomas.

Northern Pantanal lost 16 percent of its water mass in just the last 10 years.

“The Pantanal is a child of the Amazon. The rains that fall over the Paraguay River Basin and form the Pantanal come from flying rivers that originate in the Amazon rainforest,” says Walfrido Moraes Tomas of the conservation group Embrapa Pantanal. The “flying rivers” Moraes Tomas is referring to are humid, water-vapor laden air currents that carry moisture from the Amazon Basin, which falls as heavy rain over the Cerrado and Pantanal and other parts of Brazil. But as the Amazon is being razed for agriculture, ranching, and other so-called development projects at an unprecedented rate — 7,943 square kilometers of forests were destroyed in the first eight months of 2022 alone, according with the National Institute for Space Research — the rainforest’s ability to create these atmospheric rivers is diminishing.

Deforestation is ramping up in the Pantanal as well. Data from MapBiomes’ land use surveillance system reveals that the Pantanal is losing natural habitat at the rate of about 78 hectares a day — the fastest average rate of deforestation in Brazil. Land-clearing efforts that were previously restricted to the highlands along the Pantanal’s borders are now advancing into the plains. Farmers and ranchers seeking more land are taking advantage of the dry season that leaves much of the floodplain dry and vulnerable and transforming these open areas into pastures and, eventually, croplands.

From 1985 to 2021, pasture areas in the Pantanal grew nearly threefold, according to MapBiomas. Today these areas occupy 16.2 percent of the biome. A study led by Ciomara Miranda, from the Federal Institute of Mato Grosso do Sul, in Aquidauana, projects that by 2030, only 14 percent of densely vegetated areas — forests and savannas — will remain in the Pantanal. (Currently, 32.6 percent of the Pantanal is forested.)

Global warming, meanwhile, is ratcheting up the drying out of the wetlands. The Pantanal is heating faster than most parts of the world — between 3 and 4 degrees Celsius in the past four decades, while the global average rise is 1.2. The biome is one of Earth’s hotspots for rising temperatures, says meteorologist Renata Libonati, coordinator of the Laboratory for Environmental Satellite Applications of the Federal University of Rio de Janeiro.

In 2019, the prolonged dry season sparked massive wildfires in Southern Pantanal. In 2020, the region faced the worst drought in 47 years. Low rainfall slowed the wetlands’ regeneration, and the dry, windy conditions made it easier for wildfires to burn hotter and spread faster than firefighters could combat them, leading to the most devastating fires in the Pantanal’s history. Brazil’s National Institute for Space Research located 22,099 blazes that ravaged 4 million hectares in Northern Pantanal, about a third of the region. The blazes killed millions of birds, primates, rodents, snakes, and ungulates, and destroyed many homes, farms, and Indigenous territories.

The Pantanal’s savanna areas, which comprise 40 percent of its landmass, depend on wildfires to regenerate. Historically, these small-scale, low-intensity grassland fires burned through about 8 percent of the Pantanal and occurred from May to July. However, in recent years, the burning period has moved to a drier and hotter season, from July to October, and the wildfires have become more frequent and intense.

Plans to build several ports and small hydroelectric plants on the Paraguay River and its tributaries further threaten this imperiled wetland.

Libonati also points out that nearly 43 percent of the area affected by the 2020 fires were wetlands and forests in Northern Pantanal that had never burned before. “Localized seasonal fire is one thing, intense, recurrent burning another. There is no resilience against the latter,” she observes. Studies from Libonati’s team show that only 5 percent of these fires occur naturally, provoked by lightning and almost always during summer. The other 95 percent are caused by human action, intentional or otherwise.

In 2020, during the dry season, 100 percent of the fires were caused by humans.

IT IS WITHIN THIS CONTEXT that the governments of Mato Grosso and Mato Grosso do Sul have licensed the construction of several ports and small hydroelectric plants on the Paraguay River and its tributaries.

Researchers see these projects as an attempt to revive an old, 1990s transnational proposal by the Paraguay-Paraná River Basin countries — Brazil, Argentina, Bolivia, Paraguay, and Uruguay — to turn the Paraguay (and the Paraná River into which it merges in Corrientes, Argentina) into a shipping channel. That proposal, known as the Hidrovía Paraná-Paraguai, involved dredging and straightening curves in the river on hundreds of sites along its 2,202-kilometer course from the city of Cáceres in Mato Grosso to Nueva Palmira, Uruguay. It was put on hold following strong opposition from environmental, civil society, and Indigenous groups.

But under the Jair Bolsonaro regime, which was marked with environmental deregulation, local jurisdictions began going ahead with parts of it, like the ports, even though they will be viable only if the larger engineered waterway project is implemented. Critics say these smaller projects will ultimately be used by industry and state officials to justify the federal government reviving the Hidrovía Paraná-Paraguai project.

Some of these projects, such as those in the “Tramo Norte,” or the “Northern Stretch,” of the Paraguay, between the cities of Cáceres and Corumbá, are now licensed in parts, which reduces legal requirements and facilitates their approval, says Figuerôa of SOS Pantanal.

“That which walks in rails is an iron train. I’m water that runs between stones: freedom finds its way,” Manoel de Barros (1916-2014), the Pantanal’s greatest poet, reminds us, referring to the meandering paths water takes. Straightening the Paraguay’s curves might make it easier for barges to navigate the river, but its impact on wildlife, especially fish and other animals, including jaguars, who depend on these slow bends for shelter and feeding, would be irreparable, biologists say.

Meanwhile, according to Brazil’s National Water Agency, 138 small hydroelectric dams are either planned or in various stages of construction in the Upper Paraguay Basin. This is in addition to the 47 existing dams, including four large ones, in the basin that already reduce the amount of water available to the Pantanal, affect the natural flood pulses, and impede fish migration.

If all these hydroelectric plants were built, it would reduce the flow of water and sediments transported by rivers into the Pantanal by 62 percent, warns a study led by Ibraim Fantin, coordinator of the Graduate Program in Water Resources of the Federal University of Mato Grosso. The research, published in the journal Frontiers in Environmental Science, predicts that this reduction will impact the supply of nutrients that feed the biome’s food chains, creating dead zones. “Once installed, their impact will become irreversible, and will have consequences for fishing and tourism,” Fantin says.

Permits for all these projects are being considered on an individual basis, which, scientists say, doesn’t take into account their cumulative environmental and social impact. It’s what experts call the “termitization” of the Pantanal — a series of small attacks, similar to how termites degrade a piece of wood.

“Only the local disruption caused by these ports and PCHs are considered, but their damage is widespread and affects the whole basin. And if these large-scale impacts continue to be ignored, they will kill the Pantanal,” says Steve Hamilton, professor at Michigan State University, expert in the Pantanal’s hydrology for 30 years and former inhabitant of the biome. Hamilton says the “Tramo Norte of the Pantanal waterway is particularly vulnerable to interruptions due to low water levels.

“Even without climate change, occasional years with low water levels will make navigation hard or impossible, and it is expected that climate change will make these years more frequent and severe.”

Concerned by the proliferation of these piecemeal projects, in July 2022, a group of scientists, including Walfrido Moraes Tomas of Embrapa Pantanal, published a letter in the journal BioScience warning that the Pantanal was at risk of collapse due to a series of “small mistaken decisions that fail to consider their cumulative impacts” as well as “the synergy among these local threats and the climate change.”

THE PANTANAL CAN’T BE contemplated in isolation, says Marcos Rosa, technical coordinator of MapBiomas. The biome is influenced by what happens in the Amazon and it is umbilically tied to the surrounding Cerrado highlands that harbor over 4,000 river sources. So, when thinking of conserving it, it’s more useful to consider the whole Upper Paraguay Basin, a 624,320-square-kilometer region which includes the Cerrado highlands, where the water comes from, and the plains, which are flooded by the former, and parts of the Chiquitano forest and the Chaco lowlands.

“We’re overdue for an integration of the basin’s protection, “ Figuerôa says.

The Cerrado, which makes up a fourth of Brazil’s landscape, however, has even fewer legal protections than the Pantanal. Stretching across 2 million square kilometers, it is the most biologically rich savanna in the world, and, according to the World Wildlife Fund, shelters 5 percent of the planet’s species and 30 percent of Brazil’s biodiversity. It is the cradle of Brazil’s freshwater resources — rivers born here feed six of Brazil’s eight largest watersheds and the Pantanal in its entirety. It’s also an important wildlife corridor, connecting the Amazon, the Caatinga, the Atlantic Forest, and the Pantanal to each other. If the Cerrado disappears, that critical link will be broken. Yet only 3 percent of the Cerrado is strictly protected. Crops and pastures have replaced more than 50 percent of its original cover.

“We need to account for the interdependency between plains and highlands, between the environment and the Pantanal’s human culture. They are inseparable. Laws, licensing processes, and studies need to take these connections into account,” says Ikeda-Castrillon.

“Our challenge today is to show that there will be no Pantanal if we don’t take care of the surrounding highlands, and that the economy needs the environment,” says Angelo Lima, social mobility coordinator at the Pantanal Restoration Pact, a movement that unites civil society and the private sector that has been opposing the new rash of infrastructure projects on the Paraguay.

“Human action will determine the fate of the Pantanal.”

Scientists and activists are pinning their hopes on President Luiz Inácio Lula da Silva, who was re-elected last October and took office in January. Lula’s two previous terms as president were marked with pro-environment policies, and he has vowed to undo the environmental destruction unleashed by the Bolsonaro regime. Given that the large hidrovía project requires federal approval, many are counting on Lula to cancel it for good.

For now though, the fate of this unique biome hangs in the balance. “Whether in regard to climate change, [hydroelectric] plant and waterway construction, or fire use, human action will determine the fate of the Pantanal,” says Renata Libonati.

Navigating the Paraguay River today, one can get a sense of the damage these projects will cause to the already-impacted river, which sustains the Pantanal. Dona Nilza, whose life depends on the rhythms of the river, has a front row view of its diminishment. In August, she and her husband rescued the occupants of a four-seater speedboat stranded in the middle of the river, which wasn’t even half-a-meter deep at that point.

Sitting in her home — open to forest and river — she speaks of her hope that the animals will return. She wants to hear, once again, the cacophony of monkeys, see the colors of macaws, and feel the magic of jaguars. She also wishes that traditional populations of ribeirinhos (riverine people) like her, who have lived sustainably off these lands for centuries, will be consulted regarding decisions that will define the course of their lives.

This article is part of the Brazilian environmental journalism website ((o))eco’s special series Pantanal em Foco, and was originally published in Portuguese in partnership with O Globo.