Slow Recovery of Lake Chad as an Early Warning Signal for Abrupt Climate Change

Abstract:

Despite the interest generated by the shrinking of Lake Chad (LC), little attention has been paid to analyzing and detecting whether the drop in its size and level is an indicator of ecological regime shift. This understanding is important since LC wetland represents a threatened ecosystem that sustains life through the provision of critical services like fishing, water for irrigation, and biodiversity. There is thus the need to investigate and measure the slowing down in the recovery of LC. In this work, we illustrated observational-data-based analysis of detecting an impending regime shift. While we did not firmly conclude that there has been a regime change in variability of LC level based on currently available data, our results indicate the existence of a tipping point. One feature that supports this assertion is a slow recovery from the 1960s perturbation compared to the perturbations of the early 1910s and 1930s. This slow recovery in precipitation and LC level suggests a low resilience (high risk) phase in environmental change. It indicates a possible early warning signal for abrupt surface hydrological changes. As such, proactive intervention in the form of wetland restoration and enhancement should form an integral part of adaptation and mitigation measures.