Projected Increase in Extreme Flooding Events in Sahel Due to Climate Change

A recent study finds that extreme flooding events in the Sahel are projected to increase due to climate change, resulting in intensified African easterly waves (AEWs). The study highlights the relationship between AEWs and flooding, as well as the transport of Saharan dust, demonstrating how changes in atmospheric conditions could significantly impact the region’s climate and hydrologic patterns.

A recent study reveals that extreme flooding events in the Sahel are set to intensify in a warmer climate, driven by alterations in African easterly waves (AEWs). These weather systems are critical as they not only deliver precipitation to drought-prone areas in northern Africa but also facilitate the transport of Saharan dust across the Atlantic, impacting hurricane activity. The researchers utilized a comprehensive ensemble of Earth system models to predict future changes in AEW activity and underlying climatic mechanisms.

The study indicates a significant increase in wave activity over the Sahel-Sahara region by the end of the 21st century under two distinct emission scenarios. This intensification is attributed to heightened baroclinicity, stemming from a stronger meridional temperature gradient between the Guinea Coast and the Sahara. Furthermore, the findings illustrate that warming at lower levels amplifies wave activities by enhancing monsoon flow, which in turn facilitates increased convergence and vertical motion along the intertropical discontinuity.

The implications of these alterations are considerable, particularly regarding the frequency and intensity of extreme flooding resulting from meso-scale convective systems (MCSs) linked to AEWs. Moreover, the increase in AEW activity is expected to influence Saharan dust transport, particularly as the area of highest projected AEW activity is located over prominent dust sources in the western Sahara. Reinforcing this scheme, the strong winds associated with northern track AEWs could potentially hinder tropical cyclone formation or delay it, as the waves progress to areas with more favorable conditions in terms of sea surface temperatures within the Atlantic basin. This study, led by Akintomide A. Akinsanola from the University of Illinois, highlights the critical role of AEWs in regulating weather and climate in the region.

The Sahel region of Africa is characterized by its vulnerability to climate variability and change, particularly with regard to its hydroclimate and extreme weather phenomena. African easterly waves (AEWs) are significant atmospheric disturbances that greatly influence precipitation patterns and cyclogenesis within this region. Understanding the impact of climate change on AEWs is essential for predicting future weather events, including the frequency and intensity of flooding, which poses a threat to the livelihoods of millions in the Sahel.

In conclusion, the findings from the study underscore the pressing need to consider the effects of climate change on AEW dynamics, as they hold far-reaching implications for extreme weather events in the Sahel. Anticipated increases in flooding intensity and frequency necessitate adaptive strategies to mitigate the risks associated with these changes, particularly for the vulnerable populations residing in drought-prone areas of northern Africa.

Original Source: www.downtoearth.org.in