2021 is the driest year in the Pantanal since 1985, with a wetland area of 1.6 million hectares

Pantanal wetlands went from 7.2 million hectares in 1988 to 5.1 million hectares in 2018, the year of the last flood 

Data obtained by MapBiomas from the analysis of satellite images between 1985 and 2021 confirm that the Brazilian Pantanal has been showing much drier patterns in recent years. The year 2021 represents the driest ever observed, with a wetland area equivalent to 1.6 million hectares - 76% less than the beginning of the series (6.7 million hectares in 1985).  

As this is a biome where the water surface varies seasonally, the researchers evaluated the variation between years with peaks of flooding and drought. Adding up flooded grasslands and water-covered surfaces, the reduction was 29% in extreme peak flood years (from 7.2 million hectares in 1988 to 5.1 million hectares in 2018) and 66% in extreme peak drought years (from 4.7 million hectares in 1986 to 1.6 million hectares in 2021).  

In the most recent years of the series, one can see that the floods are getting smaller and smaller, both in terms of area and duration.  In 2020 and 2021 the flooded area was below the already decreasing trend, with the wetter months less expressive than the drier months of the other years in the series. 

Regardless of seasonality, the data show that all months of the year show a decreasing trend in the flooded area. Considering the monthly mapping and the area, trend, and frequency data, over the period 1985 to 2021 the Pantanal is flooding smaller areas and also for less time.

In the last 37 years, the water surface in the Pantanal has gone from 2.7 million hectares in 1985 to 500,000 hectares in 2021.  In 1985, 4 million hectares were flooded grasslands; in 2021, it was 1.1 million hectares. In the same period, the grassland formations went from 1.6 million hectares, in 1985, to 5.7 million hectares, in 2021. Agricultural activities, on the other hand, occupied 600,000 hectares in 1985 and 2.8 million hectares in 2021.  In 1985, 6 million hectares were forest and savanna; in 2021, there were 4.9 million hectares.

"The Pantanal is suffering from multiple and simultaneous local, regional, national and global degradation vectors," explains Eduardo Reis Rosa, of MapBiomas.  "At the local level we see a process of conversion of natural areas into exotic pastures. The occupation of the plateau area, without respect for the springs and areas of permanent protection along the rivers, is affecting the quantity and quality of water and causing silting up in the rivers of the plain. There is also a high frequency in the incidence of fires, which hinders the natural recovery of the biome. At the regional level, we also have the advance of dams, SHPs, artificial drains, and roads, which are compromising the flow of the waters. At a national level, we see a greater irregularity in the rainfall regime generated by the deforestation of the Amazon and the compromising of its capacity to pump moisture into the atmosphere. Finally, the Pantanal also suffers with the worsening of the climate crisis", he details. 

The conversion of natural grasslands into pastures planted with exotic species is emblematic of the process of degradation of the Pantanal. A biome that has historically been occupied by livestock activities, the Pantanal has seen the advance of exotic pastures over the natural ones as the receding waters have left larger extensions of exposed land. However, this process has left a legacy of soil degradation, more accentuated in the eastern portion of the biome:

The Upper Paraguay River Basin is formed by the lowland area (the Pantanal) and its sources in the plateau area (comprises Cerrado and Amazon areas). The basin picture in 2021 shows a large difference in preservation between the lowlands (where 83% of the area is still natural) and the plateau (only 43%). It is worth noting that all the Pantanal riverheads (+140,000) are located on the plateau, among the Permanent Preservation Areas of rivers (30m) and springs (50m) in the basin, 43% of the area is anthropic use in 2021 (656,000 ha), of this total 185,000 hectares of preservation areas were converted to anthropic use in the last 37 years. 

MapBiomas also calculated numbers for the Upper Paraguay Basin:

  • In 1985, 8.9 million hectares were forest; in 2021, there were 5.9 million - a loss of 3 million hectares in 37 years.
  • In 1985, 9 million hectares were savanna; in 2021, 7.3 million - a loss of 2.3 million hectares in 37 years.
  • In 1985, 8.5 million hectares were occupied by agriculture and cattle raising activities; in 2021, there were 14.7 million - a gain of 6.2 million hectares in 37 years. 

In all, the biome had a total of 12 million hectares of natural areas in 2021, a loss of 12% in 37 years. Last year 39.6% was occupied by grasslands, 19.7% by forests, 16.8% by pastures, 12.9% by savannahs, 7.1% by flooded grasslands and 3.5% by water.