Reconstruction of Climate Variability and Aridity Patterns over the Last Millennium in the Middle São Francisco Using Speleothems: Insights into Present and Future Climate

• Grant number: 24/22858-1
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: July 01, 2025
• End date: June 30, 2028
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Francisco William da Cruz Junior
• Grantee: Juliana de Sousa Nogueira
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 22/08359-7 - Interhemispheric monsoon precipitation patterns under different warming backgrounds in the past 140 KA and the anthropocene epoch, AP.PFPMCG.R

Abstract

Climate change poses increasing challenges to Northeast Brazil, a region recently identified as hosting the country's first arid climate center. This highlights the urgent need to understand the climatic patterns and processes shaping this area. The São Francisco River Basin (BRSF), one of the largest in Brazil and critical to the water supply and economy of semi-arid regions, encompasses diverse biomes and sustains vital economic activities. However, its hydrological regime and climate variability remain poorly understood, particularly on long-term scales. Paleoclimatic studies, which allow the analysis of past climatic patterns and cycles, are essential to distinguish natural variability from anthropogenic alterations, yet their application in Northeast Brazil is hindered by the scarcity of well-preserved records. In this context, speleothems, mineral formations in caves with widespread distribution in the region and high dating precision, represent a promising but underutilized source of paleoclimatic data for the semi-arid zone. This project aims to address this gap by conducting the first high-resolution paleoclimatic reconstruction of the last millennium for the BRSF, combining isotopic and geochemical analyses of speleothems with data integrated into climate models. This approach seeks to investigate changes in the hydrological cycle and identify mechanisms underlying extreme events such as prolonged droughts, examining the influence of global climatic modes, including Atlantic and Pacific patterns, on regional precipitation variability. Additionally, the project will assess the links between increased aridity in Northeast Brazil, local human activities, and global warming. By advancing the understanding of global and regional climate interactions, this project aims to provide a robust scientific foundation to address the climatic challenges facing Northeast Brazil. (AU)