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After a searing Amazon fire season, experts warn of more in 2025

  • South America recorded the highest number of fire outbreaks in 14 years in 2024, with Brazil at the epicenter of the crisis.
  • In the Amazon, fire outbreaks grew out of control even amid a sharp reduction in deforestation rates, indicating deforesters are relying on fire as a new technique to clear land.
  • Experts are urging more investment in fire prevention since the rainforest may face another intense fire season in 2025.

South American countries registered 511,575 fire outbreaks in 2024, the highest number since 2010. Brazil accounted for 54% of them, according to the country’s space agency, INPE, with fires mainly hitting the Amazon Rainforest, but also the Pantanal wetlands, the Cerrado savanna, and the country’s most populous state, São Paulo. The smoke spread through 10 of Brazil’s 26 states, impacting air quality and air traffic.

“The fires took on a tragedy dimension in 2024,” Suely Araújo, a senior public policy adviser at the civil society coalition Climate Observatory, told Mongabay. “It’s important to understand the causes well enough to ensure that it won’t happen again this year.”

The outbreaks were fueled by an extreme drought that hit the Amazon in 2023 and 2024. Rainfall in the biome started diminishing in 2023 due to El Niño, the abnormal warming of the surface waters of the equatorial Pacific Ocean. The two intense dry seasons saw water levels in the Amazonian rivers drop to record lows and created the perfect conditions for burning.

“The landscape became very dry, with many fallen leaves accumulating flammable material on the ground,” Ane Alencar, director of science at the Amazon Environmental Research Institute (IPAM), told Mongabay.

The record of fires in 2024 happened despite a 30% decrease in deforestation rates, contradicting previous assumptions that fires are directly related to forest destruction; historically, deforesters set fires to burn the remains of trunks and branches before growing pasture.

The historic drought that ravaged Brazil in 2024 saw water levels in the Amazonian rivers drop to record lows. Image courtesy of Juliana Pesqueira/Amazônia Real (CC BY-NC-SA 4.0).

“Decreasing deforestation will reduce sources of ignition. But there are other ignition sources, such as pasture burning,” Alencar said, referring to ranchers who use fire to renew pastures.

Under extremely dry conditions, these fires easily get out of control and reach neighboring properties and forest edges. “In the Amazon, fire always has a human origin. Nature’s contribution last year was the drought, which helped spread the fire,” she said.

According to MapBiomas, a collaborative network that maps land use, around 55% of Amazon fire outbreaks from January to September 2024 started in pastures. Another 25%, however, were generated in forest areas. It was a surprise, according to experts, since rainforest moisture usually protects the rainforest from fire. “This is very frightening,” Alencar said.

In August 2024, Rodrigo Agostinho, head of IBAMA, Brazil’s environmental agency, said fire was being used as a new deforestation tool, replacing the traditional chainsaws and tractors. “Deforestation is expensive,” Agostinho told Brazil news outlet Agência Pública. “Fire is much cheaper. You just buy some gasoline and spread it around.”

Besides being cheaper, fire is more challenging to detect by environmental agents’ satellite imagery. With the forest increasingly dry and fragmented, flames spread easily through the vegetation, facilitating the deforesters’ job. “People are using fire as a degradation tool, forcing progressive deforestation,” Alencar said.

In 2024, fire outbreaks spread throughout the Amazon, Pantanal and Cerrado biomes, as well as highly populated areas in São Paulo state. Image courtesy of Gustavo Figueirôa/SOS Pantanal.

For 2025, the forecasts aren’t good. The rainy season, expected to start at the end of 2024, began later. According to Brazil’s National Center for Monitoring and Warning Natural Disasters, CEMADEN, the Amazonian rivers haven’t recovered to their normal levels yet.

“We would have to have a good, widespread rainy season to recover from some effects of the drought, but the rainy season is weak,” meteorologist Marcelo Seluchi, general coordinator of operations and modeling at CEMADEN, told Mongabay.

In the coming months, the northern part of the Amazon, including Venezuela, Colombia and the Negro River Basin in Brazil, may experience an increase in rainfall thanks to La Niña, the cooling of the waters of the Pacific Ocean. This won’t last long, however, according to Seluchi, and won’t reach the southern part of the Brazilian Amazon, where most of the fires are usually detected. “We don’t have anything to say that it will be a good year in terms of fires; on the contrary,” Seluchi said.

This grim forecast means federal and local administrations should be working right now to prepare for the next fire season, according to Araújo from the Climate Observatory. “Money has to be spent on fire prevention and firefighting since January. You can’t wait for the fire to come,” she said.

President Luiz Inácio Lula da Silva, second left, declared a war on criminal fires, but the Federal Police have struggled to prosecute arsonists. Image courtesy of Ricardo Stuckert/PR.

Prevention measures include the creation of firebreaks, where stretches of vegetation are removed to stem the spread of fires, and training of local communities on how and when to use fire to renew pastures and clear fields.

Araújo also pointed to the role of state governments, which issue fire mandates. In Brazil, rural producers must apply for permission to use fire on their properties — at least in theory. “In practice, almost no one asks for authorization, and state agencies don’t monitor as they should,” she said.

In 2024, Brazil announced a war on criminal arsonists, and the Federal Police opened several investigations into criminal fires. However, the Brazilian newspaper Folha de São Paulo reported that only 25% of the inquiries opened since 2019 ended up in indictments.

Even when authorities find someone to blame, penalties are too mild to dissuade new episodes, according to Araújo. “Intentional arson must be strictly punished,” she said.

At least six bills designed to toughen penalties on criminal fires are currently being discussed in the Brazilian Congress, but none have been approved yet. In September, the federal government published a decree increasing the fines for forest fires at the administrative level.

Banner image: In 2024, Brazil faced its worst fire season in 14 years, and the forecast for 2025 doesn’t look good. In the image, firefighters combat flames in the Tenharim/Marmelos Indigenous Territory, in Amazonas state. Image courtesy of Mayangdi Inzaulgarat/IBAMA. 

Brazil launches ‘war’ on widespread fire outbreaks & criminal arsonists

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