South America: Water deficits in Argentina, Chile

1 March 2023

THE BIG PICTURE
The 12-month forecast ending in October 2023 indicates intense deficits scattered throughout the continent. Small pockets of mild to moderate anomalies are also scattered throughout several countries in central South America.

Exceptional deficits are expected in the following areas:

• Northwestern Venezuela, spreading from the city of Merida, further east to Guayana City.

• Southern Bolivia, near the cities of Sucre and Cochabamba.

• Western and southeastern Peru, with areas near Piura, Isconahua Indigenous Reserve, and San Martin de Pangoa experiencing the highest intensity deficits.

• Pockets throughout western into central Brazil, appearing through Acre into southern Amazonas, Para, Mato Grosso, and Mato Grosso Do Sul.

• Southern Chile, widespread throughout the region, intensifying near Santiago and spreading south into Patagonia.

• Eastern Argentina and throughout Uruguay, along the coast of Rio de la Plata, and continuing east near the Argentinean province of Rosario.

Severe to extreme deficits are forecast for:

• Central and southern Peru, near the Departments of Huánuco, Cusco, and Apurimac.

• Northern into central Chile, widespread throughout the entire area.

• Southeastern Argentina, in coastal regions north of Monte Leon National Park.

Extreme to exceptional surpluses are predicted in:

• Northern Colombia, primarily in coastal regions near the city of Barranquilla.

• Trinidad and Tobago, with widespread surpluses throughout.

• Southeastern Peru, in regions south of the Madre de Dios River.

• Pockets of Brazil, throughout various states, including northern Tocantins, central Mato Grosso, and southern Minas Gerais.

• Southern Argentina, near the province of Puerto Deseado.

FORECAST BREAKDOWN
The forecast through April 2023 anticipates exceptional deficits in eastern Argentina and the Pampas to subside, turning into mostly moderate deficits in the eastern regions, Uruguay, and southern areas of Brazil. Exceptional deficits in northwestern Venezuela, southern Chile, southern areas of Patagonia, and western Brazil are expected to persist. Widespread moderate to severe surpluses are anticipated in the northern regions of the continent, including northern and western Colombia, northern Brazil, southern Venezuela, and throughout the Guianas.

From May through July 2023, most intense anomalies are expected to disappear, with the exception of intense deficits in northern Chile. These deficits travel further north into south-central Peru, lessening in intensity to moderate to severe deficits. While northern Colombia is expected to endure persisting surpluses, much of the rest of the continent will observe normal conditions to mild deficits.

The forecast for the final months – August through October 2023 – anticipates moderate to severe deficits spread throughout Peru, Ecuador, Colombia, and into the Guianas, with some mild deficits in northern and eastern Brazil. Regions along Peru’s western coast are expected to experience moderate deficits, with exceptional deficits along the borders of Bolivia and Chile to persist.

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

IMPACTS
Climate change is worsening conditions stemming from central South America’s current multi-year drought, primarily thought to be caused by La Nina. Drought has been present in the area since 2019, with 2022 being recorded as the driest year in Central Argentina since 1960. An agricultural emergency was declared in Uruguay in October 2022 along with concerns of water scarcity and lack of access to transportation, and in 2020, deforestation in the southern Amazon increased by 205% between August 2019 and July 2020 compared to the same period a year before. Professor Paola Arias of the Environmental School of the University of Antioquia in Colombia stated that due to cutting down such a large number of the area’s trees, this resulted in less moisture being available farther south in Argentina, and ultimately worsened the area’s water shortage due to the evaporation of the little water that had remained.

The last week of February 20th was drier-than-normal for key soybean-producing regions of Argentina, and was reported as the fifth driest final week of February in over 30 years. The dry conditions are affecting soybean production and are increasing in severity as each week without rain passes, though the La Nina cycle responsible for the dry conditions is showing signs of decay. Rainfall is continuing in Brazil’s soybean production regions, which need a dry period to properly harvest soybean crops and begin planting safrinha, the second crop in the region’s double-crop agricultural system, in which two crops are grown in the same field during the same year. The ideal planting window for safrinha closed February 24th, as corn planted outside of this time tends to be affected more heavily by adverse weather, with increased risks of the crop experiencing frost and maturing in the dry season.

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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