The World’s Largest Tropical Wetland Is on Fire

The Pantanal in Brazil is a UNESCO World Heritage Site renowned for its unique biodiversity. Now, it's burning.
July 30, 2020, 12:00pm
The World’s Largest Tropical Wetland Is on Fire
Image: Alice Yo at the English language Wikipedia

The largest tropical wetland on the planet has experienced an alarming number of man-made fires this month, and experts fear the worst may be yet to come as the dry season intensifies.

Since the start of July, Brazil’s National Institute for Space Research has detected 1,573 fires within the country’s Pantanal region—the highest number recorded for the month in 22 years of records. During the first six months of 2020, the number of Pantanal fires more than doubled compared with the same period last year, impacting an estimated 1.5 million acres of land. Fire season in the Pantanal region normally peaks in September, meaning the situation could worsen, posing a severe threat to the wetlands’ unique biodiversity and to a population already reeling from Covid-19.


“The situation is serious,” said Marcos Rosa, the technical coordinator of MapBiomas, a Brazilian research initiative that produces land cover maps for the country. “We have a huge number of fires in some areas that are usually wet wetlands [in July].”

The Pantanal is a 42 million acre wetland spanning southwestern Brazil, Bolivia, and Paraguay. It’s renowned for plant and animal life, which helped a portion of it gain recognition as a UNESCO World Heritage Site. An estimated 4,700 different plants and animals call the Pantanal home, including jaguars, caimans, giant anteaters, capybaras, hyacinth macaws (the world’s largest parrot), and hundreds of fish species. All of the Pantanal’s denizens are adapted to the ebb and flow of water that enters this vast floodplain from upland savannahs during the rainy season from October to April, creating rivers of grass and giant water lily fields that slowly drain during the dry season.

The Pantanal is also adapted to fire,to an extent. Natural, lightning-sparked fires have always occurred during the dry season, and Indigenous people have long used fire to effectively manage their land. But today, it’s not uncommon for fires set by people to escape control and balloon in size, creating an unnatural situation that threatens wild ecosystems. The risk of large, out of control fires is especially high during droughts, when the wetlands transform into tinderbox-like grasslands. And this year, the Pantanal is dry. 

Poor rains in the headwaters of the Paraguay River that delivers nutrients and water to the Pantanal mean that seasonally-flooded wetlands dried out sooner than expected. “We have all these grasslands around Paraguay River free of floods now and very dry,” said Geraldo Damasceno, an ecologist at the University of Mato Grosso do Sul. “So everything is burning now.”


While Damasceno hasn’t been out in the field due to the coronavirus pandemic, he suspects some of the fires have escaped control and are having a “great impact on vegetation right now.” 

Large, out of control fires can also severely impact native animals, either killing them directly or destroying their habitat, notes Danilo Ribeiro, a biologist at the University of Mato Grosso do Sul who studies the effects of fires on Pantanal fauna.

“When we have so [little] water, then animals that are typical from water, like caimans and capybaras, will go out of the water to search for food,” said Ribeiro. “And if the fire gets those animals in those places, they will die. We could expect that the fires this year will kill much more animals than they normally kill.”

On July 15, the Brazilian government issued a decree banning fires for 120 days in both the Amazon rainforest and the Pantanal. (Climate scientists have warned that the southern Amazon could also face a particularly intense, fire-filled dry season this year, partly due to an unusual buildup of heat in the tropical Atlantic.) However, Brazilian scientists who spoke with Motherboard are doubtful that the fire ban will have much of an effect, citing both a lack of enforcement and a perception that President Bolsonaro’s government doesn’t care if citizens follow environmental rules.

“We haven’t seen a government position that is strong enough to tell the people that they have to follow the law,” said Ane Alencar, the science director at the Amazon Environmental Research Institute. Indeed, Brazil’s space agency has detected more than 1,000 additional fires in the Pantanal since the ban went into force.

Meanwhile, the state of Mato Grosso do Sul has declared a state of emergency in the Pantanal and is now receiving support from military aircraft to help douse the flames. In his emergency decree, the state’s governor cited both the environmental impact of the fires and the health risks posed by high smoke levels, which could exacerbate respiratory problems among a population already reeling from Covid-19. 

“The smoke from these big fires travels very far,” Ribeiro said. “So it will increase the respiratory problems of people. People will have to go to the hospitals, and we will lose some places that could be used for people with Covid.”