Why does Bahia’s interior experience recurring droughts?

The interior of Bahia, which occupies most of the state's land area, experiences recurring droughts primarily due to its location within a dry zone where the rainy season is irregular and annual precipitation is limited to no more than 24 inches (610 mm). This region is part of a broader area in northeastern Brazil known as the "drought quadrilateral" or "drought polygon," where annual rainfall is typically restricted to 15–30 inches (375–750 mm).12

These drought conditions are exacerbated by large-scale climate patterns, specifically the El Niño-Southern Oscillation (ENSO). During strong El Niño episodes, altered global weather patterns frequently result in significant droughts across northeastern Brazil. These shifting climatic conditions make life challenging in the sertão (the backlands of the Northeast) and have historically served as a major driver for migration out of the region. While agriculture in the interior was severely threatened by these droughts in the late 20th century, the implementation of irrigation has helped to mitigate the impact on the state's agricultural output.3421