Why is the world's largest wetland on fire?

RIO DE JANEIRO - More than 1.3 million hectares of natural vegetation have burned in South America's Pantanal this year already, with images of incinerated jaguars, monkeys and caimans flooding social media.

The burnt area amounts to nearly 9% of the Pantanal, the largest tropical wetland in the world, according to data released last week by the Laboratory for Environmental Satellite Applications from the Federal University of Rio de Janeiro. 

Scientists with World Weather Attribution, an academic collaboration studying how climate change affects extreme events, said in a report published on Thursday that human-caused climate change had made the hot, dry and windy conditions driving fires in the Pantanal 40% more intense and four to five times more likely. 

The peak of this year's fire season is yet to come, with environmentalists fearful that 2024 might see record levels of destruction, only four years after the last record season, which killed half the area's jaguar population.

What is the Pantanal?

Spanning 179,300 square km (44.3 million acres) - about the size of Uruguay - the Pantanal is formed by a mosaic of wetland and other ecosystems including forests, savannahs and grasslands, most of which are located within Brazil (78%), followed by Bolivia (18%) and Paraguay (4%).   

Although most of the Pantanal is covered by private farms, with cattle ranching its main economic activity, part of the territory is still controlled by Indigenous and other traditional riverside populations.

It is a biodiversity hot spot, with many of its species also found in other South American biomes, such as the Amazon forest and the Cerrado tropical savannah.

With more than 600 different species of birds, more than 100 species of mammals and 170 species of reptiles, the Pantanal is known for its abundance of wildlife, making it a common ecotourism destination.

However, much of its fauna is on the red list of threatened species compiled by the International Union for Conservation of Nature, including the giant anteater, the jaguar, the maned wolf and giant otter.

How bad are this year's fires?

Brazil's National Institute for Space Research detected 4,756 fire episodes in the Pantanal in the first seven months of this year, the highest number since 1999, when data started to be collected.

Although the Pantanal's dry season typically occurs from July to October, this year's fires started to gain strength as early as May.

Bolivia has also registered a record number of fires for the same period, while Paraguay had its fourth highest record.

Up until now, figures are even worse than those from 2020's historical fires, when about a third of the Pantanal's area suffered blazes, killing an estimated 17 million vertebrates. Peak fires are expected in the coming months.

The Pantanal has been warming at a faster pace than the global average, with a 2ºC increase in its average temperature since the 1980s.

In addition to global warming, this year's extreme drought has been made more intense by the El Niño climate pattern, climatologists say, but the Pantanal has been losing water for years, without a major flood since 2018.

Why is the Pantanal burning so much? 

According to data released in June by MapBiomas, a collaboration between Brazilian universities, nonprofits and tech firms, the Pantanal has lost about 81% of its surface water since 1985.

Mariana Dias, a researcher at MapBiomas, told reporters the biome had previously experienced extreme dryness in the 20th century, but said now less than 40% of its river springs were protected by natural vegetation.

Only 4.7% of Brazil's Pantanal is protected by reserves, with environmentalists warning that grain farming is expanding.

Although fires are a part of Pantanal's natural cycles, with many of its plants resistant to low intensity flames, only about 5% of the fires are thought to have natural causes, such as lightning.

Most of the fires are started by farmers to renovate pastures or finish converting natural areas into farmland after the trees have been felled, but frequently get out of control.

This year's fires are concentrated in Corumbá municipality in Brazil, which also has the highest deforestation rates in the Pantanal. 

Extreme wildfires became more than twice as frequent in the last 20 years globally, research published 2023 in the Nature journal shows, feeding into what scientists call a "climate feedback loop".

The loop means fires release carbon, exacerbating the global warming process and driving ever more fires and carbon release.

What is being done to deal with the fires?

Authorities in Brazil have banned the use of fires in the Pantanal until the end of this year.

A task force was formed with firefighters, environmental, army and police officers equipped with aircraft and boats.

Brazil's government also pays Indigenous people to carry out controlled fires to head off bigger blazes, but this year, much of the that activity had to be put on hold as vegetation became dangerously dry earlier than usual.

(Reporting by Andre Cabette Fabio; Editing by Jon Hemming.)