Recent research from HyCRISTAL has identified that the risk of increased rainfall rates under climate change is widespread across Eastern Africa. The work used a state-of-the-art climate model which provides much more detail and greatly improves the representation of storms compared to models typically used. The results indicate that average rain rates across the region could increase 40% by end-of-century under a high-end, business-as-usual scenario. The intensity of more extreme rainfall events could increase by even more.
The 2019 short rains brought heavy rain and devastating floods to many parts of Eastern Africa, with impacts being particularly acute for those already in poverty. The world has already warmed by one degree, and HyCRISTAL results show that as we experience higher temperatures we should expect a significant increase in rainfall intensities, with an increasing risk of floods such as those seen in 2019 East African Short rains.
The study also found that changes in annual rainfall accumulations were not uniform across the region, and are dependent on the local drivers of weather. Notably, along the coastline of Eastern Africa results showed little projected change in rainfall accumulation but further inland there were very large increases. This was a consequence of the sea breeze forming further inland and intensifying because of increased temperature contrast between land and ocean under climate change. There were also differentiated effects across Lake Victoria, with the East coastline showing larger increases in annual rainfall than the west.
This study has given a new perspective on the potential changes in Eastern African weather resulting from global warming. However, the study uses a single climate model. Further research is needed to expand the number of climate models used, which can increase our confidence in the projections, and better quantify the range of possible futures.
Read more and download the paper Effects of explicit convection on future projections of mesoscale circulations, rainfall and rainfall extremes over Eastern Africa.
HyCRISTAL stands for Integrating Hydro Climate Science into Policy Decisions for Climate Resilient Infrastructure and Livelihoods in East Africa. HyCRISTAL aims to develop a new understanding of climate change in East Africa and to work with the region’s decision-makers to manage water for a more climate-resilient future.
This article was written by HyCRISTAL researcher Declan Finney.