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  • Writer's pictureLigia Payão Chizolini

Understand why Brazil has arid climate areas for the first time in history

Ligia Payão Chizolini

The National Institute for Space Research (INPE) and the National Center for Monitoring and Natural Disasters (CEMADEN) released an alarming technical note about a new study conducted by both. According to the note, Brazil has unprecedentedly an area with arid climate, resembling the typical conditions of deserts. (INPE, CEMADEN, 2023).

The study considered a daily database from January 1, 1961, to July 31, 2020, and revealed a climate transformation in the north-central region of Bahia, where an arid climate was found for the first time in Brazil, covering an area of ​​more than 5,000 square kilometers. The conclusion was drawn from the calculation of the aridity index, which takes into account the region's rainfall pattern and evapotranspiration, i.e., the amount of water returned to the atmosphere.

The value obtained through the calculation serves to delineate different climatic zones. In this context, an aridity index (AI) up to 0.2 is classified as arid, while 0.5 characterizes a semi-arid region. Above 0.65, the climate is classified as dry sub-humid. Thus, the lower the number, the drier the region, as can be seen on the map presented by the technical note outlining the desert area, highlighted by the dark red line corresponding to the aridity threshold (AI) of 0.20:

The Semi-Arid is marked by high temperatures and scarce rainfall, which occur only in a few months. The predominant biome in this climate is the Caatinga, characterized by small to medium-sized vegetation. In turn, arid climate presents a chronic and permanent lack of moisture, with vegetation predominantly composed of cactus.

The desertification of the north-central region of Bahia is a result of climate change caused by anthropogenic processes and reveals how the environmental problem is already affecting the most vulnerable populations. The shift between climatic profiles increases the water deficiency in the affected region and reduces the availability of water for human and animal consumption, it´s also affects the productive activities of the territory. (Angelotti, 2009).

With desertification, it possible to observe a greater frequency of extreme events, such as torrential rains and even more severe droughts, exposing the locality to recurring climate disasters.

In an interview conducted by Natuza Nery, Fábio dos Santos Paiva, president of the Frade Farmers Association in the municipality of Curaçá, one of the municipalities located in the new arid region, shared concerns about the water scarcity plaguing the region. He emphasized the urgency of the situation, mentioning that rural residents are forced to travel up to 50 kilometers in search of water in local rivers. Additionally, the community faces the need to regularly purchase water truck services, impacting their personal incomes (Nery, 2024).

The decrease in water availability and the increase in drought also pose challenges to family agricultural production and have significant impacts on food supply in regions already affected by food problems, threatening not only the quality of life but also the very survival of the local community. (Sudene, 2021).

In this context, it is important to highlight that the high speed at which climate changes are occurring prevents the local life from properly adapting to the new climate, imposing even greater suffering on the population and punishing regional fauna and flora. As a consequence, a population exodus from the area can be expected, further exacerbating population density problems in large urban centers, causing a cascade effect of tensions in other parts of the national territory.

This rapid climate change and the consequent modification of biomes result in crop and livestock losses in various parts of the Brazilian territory, reducing its production and causing an increase in prices throughout the Brazilian consumption chain.

In view of the above, the extreme severity of the impacts of climate change on the Brazilian climate scenario becomes evident, directly affecting water availability in already vulnerable parts of the country, affecting livestock, agriculture, and the lives of thousands of people. In this scenario, it is important to intensify actions to mitigate global warming, urgently reducing greenhouse gas emissions, and also to properly adapt to existing problems and those expected to intensify in the coming years.



INPE. CEMADEN. Nota técnica: elaboração dos mapas de índice de aridez e precipitação total acumulada para o Brasil. 14.11.2023. Disponível em: 02semiaridorelatorionv.pdf ( Acesso em: 29.01.2024.

ANGELOTTI, Francislene et al, Mudanças climáticas e desertificação no semi-árido brasileiro. Editora Embrapa, 2009.

CLIMA ÁRIDO PELA PRIMEIRA VEZ NO BRASIL. Reporter: Natuza Nery. G1, 29/01/2024. Podcast O Assunto. Disponível em: 

SUPERINTEDÊNCIA DO DESENVOLVIMENTO DO NORDESTE (SUDENE.) Delimitação do semiárido. Recife. 2021. Disponível em: Acesso em: 29.01.2024.

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