The world's largest tropical wetland depends on a yearly flood, and the flood is failing. Fire weather is intensifying, water surface is at record lows. The jaguars that made the Pantanal famous are holding on where the water still comes.
The Pantanal spans close to 200,000 square kilometres across Brazil, Bolivia and Paraguay, with more than 15 million hectares on the Brazilian side, split between the states of Mato Grosso and Mato Grosso do Sul. It is a flood-pulse system: from roughly November to April, rain swells the upper Paraguay River basin and water spreads across the flat plain; from May to October it drains. That annual rhythm is the ecosystem. It sets where fish breed, where caiman and capybara gather, where jaguars hunt, and how much vegetation is wet enough not to burn.
According to MapBiomas, the Pantanal was the Brazilian biome that lost the most water surface relative to its historical average in 2024: 61% below the mean, with every one of the year's 12 months below the series that began in 1985. The biome has not seen a major flood since 2018, and it now has the smallest water surface of any Brazilian biome.
Source: MapBiomas Water, March 2025 releaseLess flooding means more of the plain dries out each year, and dried-out wetland vegetation is fuel. In June 2024, normally early in the fire season, an estimated 440,000 hectares burned in a single month, against a previous June record of 257,000 hectares. By early August more than 1.3 million hectares had burned.
A World Weather Attribution study found that human-induced warming made the hot, dry and windy conditions behind the June 2024 fires about 40% more intense and 4–5 times more likely. June 2024 was the driest, hottest and windiest June on record in the Brazilian Pantanal. The study attributes the fire weather, not the burned area itself, which also depends on ignition, land use and firefighting.
Source: World Weather Attribution, August 2024A longer-term analysis of the fire record from 1985 to 2024 reaches a consistent conclusion: reduced rainfall, shorter flood pulses and drier fuel are the main predictors of how much burns and how large individual fires get, and the fire season is lengthening.
Protection has moved forward on three levels in quick succession. Mato Grosso do Sul's 2023 state law limits clearing of native vegetation on the floodplain and created a state fund for the biome. In September 2025, Brazil enacted its first federal law specific to the Pantanal, the Estatuto do Pantanal. It sets principles for protection, restoration and sustainable use, but it was signed with 41 vetoes, including the removal of its controlled-fire chapter, which the government said should be handled in separate legislation. Environmental organizations have criticized it as too generic. Then, on 23 March 2026, Brazil expanded two federal protected areas in Mato Grosso by a combined 104,219 hectares: the Pantanal Mato-Grossense National Park and the Taiamã Ecological Station. Taiamã is the same site where jaguars were documented using the wetland as a refuge after the 2020 fires.
The Pantanal is now protected on paper at both state and federal level, and the core jaguar refuge has more formal protection than at any point before. What those laws cannot directly change is how much rain falls on the upper Paraguay basin, or how much of it reaches the plain. That makes the quality of enforcement and fire management, rather than the existence of legislation, the variable to watch.
This report carries a "Moderate, uneven by topic" Evidence Level. The fire-weather attribution and the satellite water record are strong. Other parts are thinner. Headline figures for long-term water loss vary widely between studies (from roughly 30% to over 70%) because they cover different periods, areas and definitions of "water surface". They should not be compared directly. Researchers also disagree on how much of the drying reflects natural climate variability versus deforestation and land-use change in the surrounding uplands. Jaguar population estimates for the whole Pantanal vary considerably between sources, and the effects of boat tourism on jaguar behaviour are, by researchers' own account, still based on anecdotal evidence rather than long-term data. Finally, we did not find a published burned-area total for the 2026 fire season at the time of writing.