julho, 04 2024

By WWF-Brazil

The Pantanal has been facing the driest period of the last four decades since 2019 and the trend is that 2024 will have the worst water crisis ever observed in the biome, according to a new study that is being launched today, July 3rd. The results reveal that the Pantanal did not have a flood period in 2024: in the first four months of the year, when the peak of the floods should have occurred, the average area covered by water was smaller than that of last year's dry period.

“In general, it is considered that there is a drought when the level of the Paraguay River is below four metres. In the 2024 floods, this measurement did not exceed one metre. The level of the Paraguay River in the first five months of this year was, on average, 68% below the expected average for the period”, says Helga Correa, conservation specialist at WWF-Brazil. 

“What worries us is that from now on, until October, the Pantanal tends to dry out even more. In this scenario, it is necessary to reinforce all warnings regarding the urgent need for prevention and adaptation measures to drought and to the possibility of large wildfires”, she declares.

In the Upper Paraguay River Basin, where the Pantanal is located, the rainy season occurs between the months of October and April, and the dry season, between May and September. According to the study, between January and April 2024, the average area covered by water was just 400 thousand hectares, during the flood season, below the average of 440 thousand hectares recorded in the dry season of 2023.

The study was commissioned by WWF-Brazil and carried out by the specialised company ArcPlan, with funding from WWF-Japan. Its difference in relation to other analyses based on satellite monitoring is the use of data from the Planet satellite. “Thanks to the high sensitivity of the Planet satellite sensor, we were able to map the area that is covered by water when rivers overflow. When analysing the data, we observed that the flood pulse did not occur in 2024. Even in the months in which this overflow, so important for the maintenance of the Pantanal system, was expected, it did not occur”, highlights Helga, who is also one of the authors of the study.

In addition to data from the Planet satellite for the period from 2021 onwards, the analysis of the situation in the Pantanal was also based on data from MapBiomas, obtained through the LandSat satellite, which has lower resolution, but whose historical series dates back to 1985. The researchers also analysed data from the Ladário ruler, which is one of the oldest measurements of the level of the Paraguay River.

According to the authors, the results point to a worrying reality: the Pantanal is increasingly dry, which makes it more vulnerable, increasing threats to its biodiversity, its natural resources and the way of life of the Pantanal population. The succession of years with few floods and extreme droughts could permanently change the Pantanal ecosystem, with drastic consequences for the richness and abundance of fauna and flora species, with major impacts also on the local economy, which depends on the navigability of rivers and the fauna diversity.

“The Pantanal is one of the most biodiverse wetlands in the world still preserved. It is a heritage that we need to conserve, due to its importance for people’s way of life and for the maintenance of biodiversity”, states Helga.

Degradation and climate change

In addition to climatic events that worsen the drought, the reduction in water availability in the Pantanal is related to human actions that degrade the biome, such as the construction of dams and roads, deforestation and fires, according to Helga: “The main springs in the basin of the Upper Paraguay River, which supply the Pantanal plain, are located in the highest area, in the Cerrado biome. What we observed in the Pantanal this year is very connected with impacts throughout this region in recent decades. The headwaters have been heavily deforested and there is a risk of rivers being dammed. These events reduce the Pantanal’s ability to have its flood pulses naturally”, declares Helga.

According to Helga, several studies already indicate that the accumulation of these degradation processes, accentuated by climate change, could lead the Pantanal to approach a tipping point - that is, lose its capacity for natural recovery, with an abrupt loss of species after a certain percentage of destruction.

Another concern is that successive extreme droughts and the fires they exacerbate affect water quality due to the entry of ash into the water system, causing fish mortality and removing access to water from communities. “It is necessary to act urgently and map the distribution of traditional populations and small communities that are vulnerable to drought and degradation of water quality,” she says.

Increasingly weaker floods

According to geographer Mariana Dias, geoprocessing analyst at ArcPlan and one of the authors of the Technical Note, in LandSat images, each pixel corresponds to an area of ​​30 metres, while the Planet satellite has a much more refined resolution, with each pixel representing four metres. “We can see much more detail with Planet, but we only have data from 2021. MapBiomas data, on the other hand, covers almost 40 years, which allows us to analyse trends,” she says.

According to Mariana, in addition to annual variations in droughts and floods, the Pantanal has larger cycles, which can last several years, with more severe droughts and less significant floods, or vice versa. Analysis of the data set indicates that the biome entered one of these large drier periods.

“In the 1980s, the Pantanal had a large period with stronger floods, with larger areas remaining flooded for longer. What we are observing now is that the area flooded during floods is getting smaller and smaller. So we have more areas becoming dry, with flooded areas staying wet for less time. All of this creates instability in the ecosystem”, comments Mariana.

According to her, 2018 was the last year with a major flood in the Pantanal. “As of 2019, the biome began to experience the driest period we have observed since 1985. Combining data on the level of the Paraguay River in Ladário city and the maximum and minimum water surface areas mapped by MapBiomas, we show that the floods are increasingly smaller in recent years”, she declares.

In 2020, already during the driest period in the Pantanal in the last four decades, an extreme drought hit the biome, causing uncontrollable wildfires that consumed a third of its entire area.

Largest water loss: Corumbá

In the period analysed by the new study, from 2021 onwards, the year with the biggest floods was 2023, when around 660,000 hectares of water surface were recorded. The years 2021 and 2022 had a maximum water surface of just over 520,000 hectares during the full season. In 2024, the maximum water surface was just 430,000 hectares.

“In 2021, a very dry year, the maximum elevation of the Ladário ruler was 1.8 metre in the rainy season and 1.7 metre in the dry season - the lowest values ​​since the 1970s. In 2021 and 2022, all months had lower quotas than the average of the last 30 years. And in 2024 the situation is even worse”, says Mariana.

The study also showed that of the 15 Pantanal municipalities, only Ladário did not show a reduction in water surface in 2024, compared to last year. Even in a comparison with 2021, the driest year in the analysed period, there was a reduction in water surface in almost all municipalities.

Corumbá, which is the largest municipality in the biome, with an area of ​​6.5 million hectares, is also the one that lost the most water surface in 2024, compared to 2021, according to the study: a reduction of around 20,400 hectares. In second place in water surface loss, Poconé had a reduction of just over 18,205 hectares. “Corumbá occupies around 60% of the biome, so the municipality’s data is also a kind of summary of what is happening in the Pantanal. But in almost all municipalities, 2024 could be a drier year than 2021, the driest in the series analysed in the study”, comments Mariana.

Solutions

In the Technical Note, the study authors highlight that the Pantanal needs Nature-Based Solutions and actions to prevent and adapt to extreme events, mainly droughts and high temperatures, in order to avoid permanent socio-environmental damage.

The note also makes a series of recommendations, such as:

● Map the threats that cause the greatest impacts on water bodies in the Pantanal, considering mainly the dynamics in the headwater region.
● Strengthen and expand public policies to curb deforestation.
● Restore Permanent Protection Areas in the headwaters, in order to improve water infiltration and reduce soil erosion and siltation of rivers, increasing the quality and amount of water in both the plateau and the plain.
● Support the valuing of communities, land owners and the productive sector that develop good practices and scale up sustainable productive actions.

In addition to Helga Correa and Mariana Dias, the other authors of the Technical Note “Early warning to mitigate impacts of drought in the Pantanal” are Marcos Reis Rosa, Eduardo Reis Rosa, Veronica Maioli, Cyntia Santos and Maria Eduarda Coelho.

About WWF-Brazil

WWF-Brazil is a Brazilian NGO that has been working collectively for 27 years with partners from civil society, universities, governments and companies across the country to combat socio-environmental degradation and defend people's lives and nature. We are connected in an interdependent network that seeks urgent solutions to the climate emergency.