Assessment of Central Sahel Crisis by Nighttime Light Imagery

The Central Sahel region is beset by ongoing armed conflicts and confronts a critical humanitarian crisis. Nighttime light data can serve as a valuable, objective source for monitoring conflict crises. In this study, we quantified total nighttime light (TNL) and the change rate of TNL in the Central Sahel region and analyzed the correlation between TNL and the number of conflicts using a fixed-effects regression model. For large conflict events, such as the Malian civil war and the siege in Burkina Faso, we conducted more detailed local analyses using nighttime light data to assess the impact of the conflict. The results indicate that the number of conflicts in the region has been on the rise since 2012, and there is a significant negative correlation between TNL and the number of conflicts, with an R2 of 0.515. The Malian civil war in 2012 led to an 80% decline in TNL in Kidal and Timbuktu, accompanied by a massive refugee outflow to refugee camps in neighboring countries, where TNL gradually increased. In Burkina Faso, TNL in reported besieged cities has significantly decreased since 2019. In addition, we identified four unreported suspected besieged cities: Namssiguia, Boala, Bourzanga, and Tougouri. It is anticipated that the findings of this study will enhance the international community's understanding of the situation in the Central Sahel region and enable more effective assistance.