Recent Changes in Lake Chad’s Surface Water Extent: A Remote Sensing Assessment Using Sentinel-2 Land Cover Data (2017-2025)

Umar Yusuf , Umar Zulkifil Usman

Lake Chad is an endorheic freshwater lake located at the junction of four countries; Nigeria, Niger, Chad, and Cameroon in West-Central Africa. Lake Chad, once one of Africa’s largest freshwater bodies, has experienced significant hydrological fluctuations over the past decades. While long-term historical analyses highlight a severe 90% surface area contraction since the 1960s, short-term operational variations over the last decade require precise quantification to inform active transboundary water management strategies. To address this critical gap, this study aims to develop a replicable remote sensing framework using high-resolution satellite data to quantify Lake Chad’s open water and flooded vegetation dynamics from 2017 to 2025, providing evidence-based insights for sustainable water resource management. The methodology encompasses a comprehensive remote sensing analysis of the contemporary surface water extent of Lake Chad using the high-resolution (10-meter) Esri Sentinel-2 Land Use/Land Cover (LULC) time-series dataset. Through a systematic methodology involving image clipping, reclassification, and area calculation, the study tracked changes in open water, flooded vegetation (wetlands), and total lake system extent. Findings reveal a substantial recovery of the lake system, with total area expanding from 5,808.12 km² in 2017 to 11,588.14 km² in 2025, representing an absolute net growth of 5,780.02 km² (99.5% increase). While the lake has not fully recovered to its historic 1960s extent of approximately 25,000 km², it currently exhibits its most water-abundant state since the turn of the 21st century. These findings have significant implications for water resource management, regional food security, and the livelihoods of approximately 50 million people dependent on the Lake Chad basin.