Human-Induced Climate Change Increased 2021-2022 Drought Severity in Horn of Africa

Abstract

From October 2020 to early 2023, Eastern Africa experienced five consecutive failed rainy seasons, resulting in the worst drought in 40 years. This led to harvest failures, livestock losses, water scarcity, and conflicts, leaving approximately 4.35 million people in need of humanitarian aid. To understand the role of human-induced climate change in the drought, we analysed rainfall trends and the combined effect of rainfall deficit with high temperatures in the Southern Horn of Africa covering parts of southern Ethiopia, southern Somalia, and eastern Kenya. We employed various climate models and observations to assess changes in 24-month rainfall (2021-2022), and seasonal rainfall; both the (March-April-May, MAM) ‘long rains’ and (October-November-December, OND) ‘short rains’ in 2022. We also contextualised the event in terms of vulnerability and exposure to understand how these elements influenced the magnitude of the impacts. Our analysis shows that anthropogenic influence on the combined effects of low rainfall and high evapotranspiration caused by higher temperatures made the drought exceptional, leading to major crop and pasture losses and water shortages. Our results also show a decline in rainfall during MAM and an upward trend during OND, which is attributable to climate change. Despite the wetting trend in OND season, the drought years concluded with successive La Niña conditions, typically linked with below-average rainfall in the region during that season. We do not find a trend in the 24-month precipitation. The assessment on vulnerability and exposure highlights the need for enhanced preparedness of government drought management systems and international aid infrastructure for future severe and prolonged droughts. The study's findings, combined with climate projections that indicate increased heavy precipitation in the region, underscore the pressing necessity for robust adaptation strategies that can address both wet and dry extremes. The impacts of climate change in Eastern Africa necessitate investments in adaptive measures and resilience building that can evolve with emerging climate signals.

Keywords: Climate Change, attribution, Drought, Horn of Africa