Nearly a quarter of Brazil's territory has experienced fire at least once between 1985 and 2023. This amounts to 199.1 million hectares, equivalent to 23% of the country's total area.
Of the burned area, 68.4% was native vegetation, while 31.6% had human activity, notably agriculture and livestock. The Cerrado and the Amazon are the primary biomes affected by fires, whether natural or human-induced, comprising 86% of the burned area.
These findings, based on satellite image comparisons, are part of a study released this Tuesday (18) by MapBiomas Fogo, a network involving universities, non-governmental organizations (NGOs), and technology companies.
Through satellite images, researchers can analyze the size and historical patterns of burned areas, although pinpointing the exact cause of the fires remains challenging. However, Ane Alencar, coordinator of MapBiomas Fogo and Science Director at the Amazon Environmental Research Institute (Ipam), explained to Agência Brasil that most fires likely do not have natural origins, such as lightning strikes.
“We can infer that the vast majority of fires are caused or initiated by human activities,” stated the geographer.
This conclusion is primarily based on the timing of most fires, which are concentrated in August and September.
“Where it burns the most—Cerrado, Amazon, and now, unfortunately, the Pantanal—is during the dry season, when it is quite unlikely for lightning storms
to occur,” detailed Ane Alencar.
The dry season, from July to October, accounts for 79% of the burned areas in Brazil, with September alone representing one-third of the total.
Alencar noted that most of the burned native vegetation remains uninhabited by humans. "A small percentage of the affected areas mainly become pastureland."
Nearly half (46%) of the burned area is concentrated in three states: Mato Grosso, Pará, and Maranhão. Out of every 100 burned hectares, 60 are on private lands. The three municipalities that burned the most between 1985 and 2023 were Corumbá (MS) in the Pantanal, followed by São Felix do Xingu (PA) in the Amazon, and Formosa do Rio Preto (BA) in the Cerrado.
The study also revealed that about 65% of the affected area was burned more than once between 1985 and 2023. On average, 18.3 million hectares—slightly less than the size of Sergipe—burn each year.
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