RIO DE JANEIRO, BRAZIL – The federal government is to issue a water emergency alert for the June to September period in 5 Brazilian states – Minas Gerais, Goiás, Mato Grosso do Sul, São Paulo and Paraná.
They are all located in the Paraná River basin, where part of the country’s agricultural production and large hydroelectric plants are concentrated. The situation in the region is classified as “severe” and the forecast is for low rainfall for the period.
It is the first alert of this kind in 111 years of meteorological services in the country. The measure corroborates Bolsonaro and Minister Bento Albuquerque’s statements that Brazil is facing the worst water crisis in recent times.
The alert will be issued today, May 28, in a joint statement by the National Meteorology System (SNM), federal weather agencies, the National Water and Basic Sanitation Agency (ANA) and the National Center for Monitoring and Alert of Natural Disasters (CEMADEN).
In the document, the institutions stress that the water emergency is associated with the scarcity of rainfall in the hydrographic region and the forecast that the scenario will persist until September.
According to the SNM, the rainfall deficit in the Paraná basin is likely related to the influence of two large-scale atmospheric phenomena. The first is La Niña, from October 2020 to March 2021.
The phenomenon causes the waters of the Pacific Ocean to cool, lowers the sea surface temperature, changes the global circulation pattern, and, among the features for the period, reduces rainfall in southern Brazil.
The second is the Antarctic Oscillation (AAO), responsible for changing the atmospheric pressure pattern in the region. Since October 2020 the AAO has been preventing rainfall-causing systems from moving over the continental regions of South America.
However, the rainfall scarcity situation predates this. According to a survey conducted by the agencies through the analysis of rainfall between October 2019 and April 2021 in the Paraná basin, rainfall was only above average in December 2019, August 2020, and January 2021.
“During most of the period there was a predominance of a deficit in rainfall, especially from February 2021 on. This pattern is maintained this month, with a partial accumulation of 27 millimeters for the basin, i.e. below the normal climatological accumulation, which is 98 millimeters,” reads the alert text.
The SNM warns that the rainfall index in most of the basin is moderate to extreme, considering the past 6 and 12 months, as well as in an analysis of a longer period, the past 48 months. In other words, the current rainfall deficit situation is severe.