Satellite evidence for persistent degradation in Brazil's desertification nuclei

Desertification is a major global environmental challenge, driven by both human activities and climate variability, leading to the suppression of natural vegetation through agricultural and livestock expansion. This study aimed to (1) characterize desertification nuclei in Brazil using ecological indicators, (2) assess land use impacts, and (3) explore relationships with social and agrometeorological factors. Landsat imagery (1991, 2000, 2010, 2022) and TerraClimate data were examined alongside population and HDI statistics for six nuclei: Cabrobó, Gilbués, Inhamuns, Irauçuba, Jaguaribe, and Seridó. Results indicate that desertification advances even during rainiest years influenced by La Niña, and is intensified by droughts linked to El Niño. Exposed soils and pastures were consistently the most degraded land-use classes, particularly in Ceará, while agriculture and Caatinga areas were most affected in Cabrobó and Seridó. Gilbués and Seridó emerged as the most critical nuclei, with expansion driven by unsustainable agricultural frontiers and population pressure. Overall, findings highlight the urgent need for continuous monitoring and improved spectral indicators to better capture desertification dynamics and support mitigation strategies in Brazil’s semiarid region. • Degradation is widespread but varies in intensity and drivers across nuclei. • Exposed soil and pasture are consistently the most vulnerable land use classes. • Agriculture expansion is a critical factor in Gilbués, Jaguaribe, and Seridó. • Climatic variability (El Niño/La Niña) modulates but does not halt degradation. • Population growth and socioeconomic pressures intensify desertification.