Brazil’s water surface area shrinks below historical average in 2023
The surface area of water throughout Brazil dropped below the historical average in 2023, a MapBiomas Água survey released this week shows. Last year, water covered 18.3 million hectares, or two percent of the national territory, down 1.5 percent from the historical average, first calculated in 1985.
Water losses were reported in all months of 2023 compared to 2022, including in the rainy season. In 2022, the water surface reached 18.8 million hectares. The figures refer to 1985 through 2023. The survey says that the biomes have been suffering from the loss of water surface since 2000, with the 2010s being the most critical decade.
In 2023, natural water bodies accounted for 77 percent of Brazil’s water surface, down 30.8 percent—6.3 million hectares—compared to 1985. The other 23 percent are anthropogenic bodies, i.e. water stored in reservoirs, hydroelectric dams, aquaculture, and mining, which adds up to 4.1 million hectares. Of this total, large reservoirs account for 3.3 million hectares, up 26 percent in 2023 from 1985.
“While the cerrado and the caatinga are experiencing an increase in water surface as a result of the creation of hydroelectric dams and reservoirs, others—such as the Amazon and the Pantanal—are facing severe reductions, leading to significant ecological, social, and economic impacts. These trends, aggravated by climate change, highlight the urgent need for adaptation strategies for water management,” Juliano Schirmbeck, technical coordinator of MapBiomas Água, said in a statement.
The Amazon
More than half of Brazil’s water surface is in the Amazon—62 percent of the national total. In 2023, the biome had a water surface of almost 12 million hectares, or 2.8 percent of the biome’s surface. This represents a decrease of 3.3 million hectares compared to 2022.
The organization points out that the Amazon suffered a severe drought in 2023, with the water surface area below the historical average from July to December, and October through December reporting the smallest areas in the time series. The episode led to the isolation of populations and the death of fish, dolphins, and tucuxis.
The pantanal
The surface area of water in the pantanal in 2023 reached 382 thousand hectares, 61 percent below the historical average. The organization points out there has been a reduction in the area flooded and the length of time during which the water remains. Last year, only 2.6 percent of the biome was covered in water. The pantanal accounts for two percent of Brazil’s total water surface.
The year of 2023 was 50 percent drier than 2018, when the last major flood occurred in the biome. According to MapBiomas, in 2018, water in the Pantanal was already below the average in the time series, which has compared data since 1985. In 2024, no flooding has been reported to reach a high point, and the year has seen a peak of drought likely to last until September.
The cerrado
In 2023, the cerrado had its largest water surface since 1985, reaching 1.6 million hectares, or nine percent of the national total. The figure is 11 percent above the historical average for the biome. The organization explains that the gain in water surface area occurred in anthropogenic areas, which surged by 363 thousand hectares, up 56.4 percent. Natural bodies of water, on the other hand, lost 696 thousand hectares, down 53.4 percent.
Last year, natural bodies of water occupied 608 thousand hectares of the cerrado, or 37.5 percent of the biome’s water coverage. The remaining 62.5 percent was mainly divided between hydroelectric dams (828 thousand hectares, 51.1 percent) and reservoirs (181 thousand hectares, 11.2 percent).
“Since 2003, the surface area of water used to generate energy and supply urban centers has exceeded the area of natural water in the cerrado. However, these reservoirs are supplied by natural bodies of water that have shrunk in recent decades,” Joaquim Pereira, from MapBiomas, said in a statement.
The caatinga and the pampa
After a long period of drought, which lasted seven years and proved to be one of the longest droughts in the Northeast since 2018, MapBiomas shows an upward trend in the surface area of water in the caatinga and the consolidation of a wetter cycle in the biome. Last year recorded a water surface of almost 975 thousand hectares, six percent above the historical average and five percent of the national total.
Ten percent of Brazil’s water surface in 2023 was in the pampa—more than 1.7 million hectares, or 9.2 percent of the biome’s territory. Last year’s water surface was 1.3 percent lower than in 2022. According to MapBiomas, in 2023, the pampa saw the driest first four months of the time series. The floods in Rio Grande do Sul state from September to November recovered the water surface in the pampa, but it still remained two percent below the historical average.
The Atlantic forest
The surface area of water in the Atlantic Forest in 2023 was three percent above the historical average, surpassing 2.2 million hectares or 12 percent, ranking second in the national total, as per the survey data. Water accounts for two percent of the biome's surface area.
The organization points out that the Atlantic Forest recorded high levels of rainfall in some municipalities last year, leading to flooding in agricultural areas as well as landslides. This is the biome with the largest surface area of anthropogenic water, where the surface area of water in hydroelectric dams and reservoirs is greater than the surface area of natural water.
