Lake Chad, in the Sahelian zone of west-central Africa, provides food and water to ~50 million people and supports unique ecosystems and biodiversity. In the past decades, it became a symbol of current climate change, held up by its dramatic shrinkage in the 1980s. Despites a partial recovery in response to increased Sahelian precipitation in the 1990s, Lake Chad is still facing major threats and its contemporary variability under climate change remains highly uncertain. Here, using a new multi-satellite approach, we show that Lake Chad extent has remained stable during the last two decades, despite a slight decrease of its northern pool. Moreover, since the 2000s, groundwater, which contributes to ~70% of Lake Chad’s annual water storage change, is increasing due to water supply provided by its two main tributaries. Our results indicate that in tandem with groundwater and tropical origin of water supply, over the last two decades, Lake Chad is not shrinking and recovers seasonally its surface water extent and volume. This study provides a robust regional understanding of current hydrology and changes in the Lake Chad region, giving a basis for developing future climate adaptation strategies.

乍得湖位于非洲中西部的萨赫勒地区，为约5000万人提供食物和水，并支持独特的生态系统和生物多样性。在过去的几十年中，由于1980年代的急剧萎缩，它成为了当前气候变化的象征。尽管由于1990年代萨赫勒地区降水增加而部分恢复，但乍得湖仍面临主要威胁，其在气候变化下的当代变异性仍然高度不确定。在这里，我们使用一种新的多卫星方法，显示了乍得湖的范围在过去的二十年中一直保持稳定，尽管其北部湖泊略有减少。此外，自2000年代以来，占乍得湖年度储水量变化约70％的地下水由于其两个主要支流提供的水而不断增加。我们的结果表明，在过去的二十年里，与地下水和热带水源一起，乍得湖没有萎缩，并且季节性恢复了其地表水的范围和数量。这项研究为乍得湖地区当前的水文学和变化提供了有力的区域性理解，为制定未来的气候适应策略提供了基础。