Evolving dynamics of lagoons in a megacity: Insights on climate and urbanization over four decades

Abstract

Lagoons are critical coastal ecosystems that serve as buffers against climate change impacts while supporting biodiversity and socio-economic activities. However, these systems are increasingly threatened by the combined pressures of urban expansion and climate variability, particularly in rapidly growing megacities. This study investigates the dynamic transformation of the Lagos lagoon systems in West Africa, comprising Epe, Ologe, Lagos, and Lekki Lagoons over four decades (1984–2024). Lagos, a megacity, is an ideal case due to its rapid urban growth, economic significance, and unique coastal dynamics. Using an integrated approach that combines satellite-derived geospatial data with hydrological and climatic analyses, we quantify long-term changes in lagoon area, volume, temperature, and rainfall trends. Contrary to global patterns where urbanization typically results in lagoon shrinkage, our findings reveal a significant expansion in lagoon area and volume, primarily driven by anthropogenic modifications such as land reclamation and sedimentation, as well as broader climatic factors, including sea-level rise and tidal surges. These results highlight the complex interplay between natural and anthropogenic drivers of coastal change, emphasizing the necessity for adaptive management strategies. Importantly, our study contributes to a broader understanding of lagoon system responses to external stressors and provides a foundation for developing evidence-based policies and nature-based solutions to mitigate the adverse impacts of urbanization on coastal ecosystems.