Dozens of scientists are sounding the alarm that carving a commercial waterway through the world’s largest wetlands could spell the “end of an entire biome”, and leave hundreds of thousands of hectares of land to be devastated by wildfires.
The Pantanal wetland – which falls within Brazil, Bolivia and Paraguay, covering an area almost half the size of Germany – is facing the proposed construction of a commercial waterway, as well as the expansion of industrial farming and spread of intense wildfires. A cohort of 40 scientists say the waterway development represents an existential threat to the ecosystem: reducing the floodplain, increasing the risk of fires and transforming the area into a landscape that could more easily be farmed.
Prof Karl M Wantzen, an ecologist from the University of Tours, and Unesco chair for river culture, said the wetland “is a real paradise on Earth. Nowhere else will you see so many hyacinth macaws, jaguars, swamp deer, anacondas, caymans, more than 300 fish species, 500 bird species, 2,500 species of water plants … All of that is at risk.”
The Brazilian government wants to develop the upper 435 miles (700km) of the Paraguay River into the Paraguay-Paraná hidrovia (waterway). In 2022 and 2023, preliminary licences were issued for the construction of port facilities within the Pantanal.
“If the hidrovia project goes ahead, navigation of large train barges in the Pantanal, with dredging in critical reaches of the Paraguay River, will probably mean the end of the Pantanal as we know it,” said Pierre Girard from the Federal University of Mato Grosso and Pantanal Research Center. “Reducing the annually flooded area, [coupled] with climate change and increased pressure on land use in the biome will increase the risks of destructive fires like the catastrophic ones seen in 2020 [when nearly a fifth of the area burned].”
In 2024, fires were the worst on record, with nearly 1.5m hectares (3.7m acres) burning across the Brazilian Pantanal by early August. Since 1985, the Pantanal has lost about 80% of its surface water – more than any other biome in Brazil. If the waterway goes ahead it is likely to further shrink the wetland, making it even more dry and vulnerable to wildfires such as those seen in 2020.
The upper section of the Paraguay River is sinuous and shallow. Making it navigable for 50-metre barges would mean extensive dredging, fixing of riverbanks and construction of ports. This would permanently alter the natural cycle of flooding and shrink the wetland area, researchers warned. Wantzen and Girard are two of more than 40 scientists who wrote a paper, published in the journal Science of the Total Environment, arguing that the waterway must not be expanded into the wetlands.
Wantzen, the lead author, said he and his colleagues published it because “I really want the world to know what’s happening. I wanted to gather people to spell out what the current situation is. It would be a senseless tragedy.”
“The Paraguay River flowing through the Pantanal is the last large riverscape in central South America that still has near-natural structure. It represents the biocultural heritage of the Brazilian people and the entire world,” researchers wrote.
Dredging this area would result in “severe degradation of the globally outstanding biological and cultural diversity of the Pantanal”, the paper warned. The wetland is also home to Indigenous peoples whose livelihoods would be threatened. The paper said railways would be a more reliable and less disruptive way to transport goods.
The growth of industrial soya bean farming has driven demand for a commercial waterway to transport goods from areas of production in Brazil, Paraguay and Bolivia to the coastal seaports in Uruguay and Argentina. Barges would also carry sugar, corn, cement, iron and manganese. The markets for these goods is North America, Europe and Asia.
The argument for creating the waterway is that barges would be faster and cheaper than transporting these goods by truck. Due to the climate emergency and reduced flooding, even with dredging, scientists believe the water level in the river would be too low to allow navigation.
“Humanity is crazy, destroying everything it can and at high speed,” said Mario Friedlander, who works in wildlife observation tourism and photography in Mato Grosso. “The operation of the waterway in the Pantanal is yet another serious attack against a place that is powerful in nature, but completely unprotected.”
Friedlander said that agricultural expansion had been one of the main developments destroying the area. He said: “We have so many fronts of destruction here, that I no longer know where to start the defence”
Responding to concerns raised by the scientists, the Brazilian Ministry for Ports and Airports said the paper contained “opinions” without “scientific elements to support them”.
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