South America: Deficits persist in Amazonas, Bolivarian Nations

19 December 2024

THE BIG PICTURE

The forecast for the 12-month period ending in August 2025 indicates that exceptional deficits will continue in Amazonas and the Bolivarian Nations, but will diminish in size.

Severe to exceptional deficits are expected in:

Western Brazil, throughout the state of Amazonas, as well as northern areas of Mato Grosso and southern Para.
Northern and eastern Peru, within the Loreto and Ucayali regions, as well as in western coastal regions of the Piura Region. Areas near the city of Cusco will also observe these deficits, as well as isolated portions of south-central and northeastern Bolivia.
Southwestern and northeastern Colombia, throughout the Caqueta department and into the Casanare department, as well as throughout north-central Venezuela. These deficits are also expected to be widespread in western and eastern Ecuador.
Northwestern Argentina, in western areas of the Catamarca and Salta provinces.

Moderate to severe surpluses are anticipated in:

Northern Argentina, in central to eastern Salta, as well as some regions of the Jujuy province.

The 3-month maps (below) show the evolving conditions in more detail.

FORECAST BREAKDOWN

The forecast through February 2025 indicates that exceptional deficits in the Amazon and Bolivarian Nations will continue, but begin to diminish in size. Northeastern portions of Brazil’s Amazonas state will observe continued exceptional deficits, as will northern and southern areas of Mato Grosso. These deficits will also continue in southern to northeastern Colombia, northeastern Peru, and west-central Venezuela. Further south, severe to exceptional deficits will persist in isolated regions of central to northeastern Bolivia, southern Chile, and the Buenos Aires, Santa Fe, and Entre Rios provinces of Argentina. Moderate surpluses will emerge in central to eastern portions of Argentina’s Salta province, as well as some regions of the Jujuy province.

From March through May 2025, moderate to extreme surpluses are expected to continue in the Amazonas region of Brazil, as well as in nearby states and throughout much of Colombia. Extreme to exceptional deficits are expected to occur in isolated regions of western Peru and southern Ecuador. Moderate to severe deficits will continue in eastern Argentina in the Buenos Aires province. Most other South American countries will observe near-normal conditions and abnormal surpluses.

The forecast for the final months – June through August 2025 – predict that severe to exceptional deficits will occur along southwestern areas of Colombia, western Peru, and southern Ecuador. Moderate surpluses will persist in Brazil’s Amazonas state and in north-central Argentina. Near-normal conditions will continue in most other South American countries.

Please note that WSIM forecast skill declines with longer lead times.

IMPACTS

A recent study found that El Niño exacerbates drought in the Amazon, both negatively affecting groundwater supplies and increasing the wildfire risk. Satellite data revealed declining levels of humidity in the region’s topsoil and groundwater during droughts, and that groundwater took the longest to recover. As the Amazon’s vegetation primarily relies on groundwater during drought, trees with shallower roots are most likely to die off and worsen potential fires. Manmade ignitions also increased the frequency of wildfires in the Amazon, as over 132,000 fires were recorded in the Brazilian Amazon by mid-November 2023, the highest since 2010. El Niño events are expected to continue to intensify in frequency and severity, which will further amplify fire risks and vegetation stress.

A new study found that tropical glaciers in the Andes region have reached record-low levels, which could potentially reduce the water flow to the Amazon rivers by up to 20 percent. The region’s glaciers have reached their smallest sizes in at least 11,700 years, with experts identifying that Andean glaciers are smaller now than at any point during the current geological epoch, potentially marking a transition to a new geological epoch, the Anthropocene.

In 2024, Bolivia experienced a record number of wildfires, which significantly impacted the region's ecosystem and air quality. Over 89,725 fires were recorded – the highest number since satellite monitoring began in 2002 and surpassing the previous record in 2010. More than 15 million hectares were burned, emitting over 100 megatons of carbon—the highest in two decades. The causes of these fires include land clearing, pasture burning, and extreme droughts. The fires severely damaged local forest, including the Amazon and Chiquitano dry forests, which left long-lasting ecological and atmospheric consequences.

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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