Tumelo Mohomi

Increasingly frequent hydroclimatic extremes in South Africa necessitate a robust understanding of how changing climate drivers will influence regional water balance. This study evaluates the impacts of climate change on hydrological extremes within the Limpopo River Basin, a region historically vulnerable to catastrophic flooding and prolonged droughts. The INM RAS-MSU (Terrestrial Model; TerM) Land Surface Model was used to project river flow from 2020 to 2100. The atmospheric forcing was derived from the CMIP6 ISIMIP database under the SSP1-2.6 and SSP5-8.5 scenarios. Projections for the near future (2020–2055) and far future (2065–2100) periods were compared against a 1979–2014 baseline, with high-flow events (floods) computed at the 95th percentile. Intra-annual streamflow patterns remain consistent with historical trends but are projected to peak by more than 50%, particularly under the high-emission (SSP5-8.5) scenario. Peak flow increase will likely occur during the austral summer (January-February), while a pronounced decrease is projected during spring (September-November). Despite an increase in pronounced peaks in rainfall, evaporation, and runoff in May, the basin exhibits a statistically insignificant decreasing trend in these variables and annual streamflow between 2020 and 2100. This suggests a shift towards a more volatile regime, with intensified high-flow extremes in January and February punctuated by increasing dry conditions in March and September. Climate change is expected to intensify hydroclimatic extremes in northeastern South Africa, where austral summer rainfall variability is strongly influenced by tropical cyclones, the El Niño–Southern Oscillation (ENSO), and convective rainfall. The findings provide an evidence base for strengthening climate adaptation policies and measures to reduce the impacts of hydroclimatic extremes in northeastern South Africa.

Over the past few decades, South Africa has experienced recurrent drought events of varying intensity. The Musina Local Municipality is particularly vulnerable due to a semi-arid climate, erratic rainfall, and rising temperatures which collectively contribute to heightened environmental stress. This study analyzed drought spatiotemporal patterns, livelihood impacts, and associated coping strategies in Musina from 1991 to 2023. Adopting a mixed-method approach, the research integrated quantitative climate data from the Copernicus Climate Data Store with qualitative insights gathered through semi-structured questionnaires administered to local community members. Drought frequency and distribution were examined using rainfall anomalies, temperature trends, and the Standardized Precipitation Evapotranspiration Index (SPEI). With more than 15 drought events recorded between 1991 and 2023, the findings indicate that Musina experiences recurrent drought episodes including major drought events in 1991–1992 and 2015–2016, characterized by rising temperatures that intensify evapotranspiration and exacerbate water scarcity. SPEI results highlight repeated drought conditions over the study period, with over 14 identified episodes and variable recovery periods, while notably negative values during major events (1991–1992 and 2015–2016) reflect severe moisture deficits associated with elevated temperatures. These climatic shifts have significantly undermined agricultural productivity, livestock health, and household water security, thereby threatening overall livelihood stability. More than 50% of the households experienced water shortages, with 17% reporting crop losses and 17% livestock mortality. While the study identified various coping mechanisms—such as reliance on boreholes, government water aid, conservation agriculture, and livelihood diversification—community vulnerability remains high due to limited water infrastructure and ongoing climate variability. These results contribute to efforts to reduce localized drought risk by providing a detailed understanding of drought dynamics and the effectiveness of community-based adaptation strategies in Musina.

The escalating impacts of climate change pose a significant risk to South Africa’s water resources and infrastructure, particularly as a result of increased frequency and intensity of extreme rainfall. This study presents extreme rainfall projections for the country by analysing Phase 6 of the Coupled Model Intercomparison Project (CMIP6) Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) global climate models (GCMs) from 2020 to 2100, under SSP1-2.6 and SSP5-8.5 scenarios. Five models and their ensembles were evaluated against ECMWF ERA5-Land and station data using Taylor diagrams, NSE, RMSE, PBIAS, and R². The ensemble outperformed individual models, which showed a similar spatial bias, underestimating rainfall over the escarpment while overestimating it in the lowlands. Rainfall changes were analysed for the near- (2020–2055) and far-future (2065–2100), focusing on the 5th, 50th, and 95th percentiles. Future midlatitude and subtropical circulation changes were projected to intensify the west-east rainfall gradient, leading to a drier west and a wetter east. This trend drives an overall increase in extreme rainfall events across South Africa. Annually, this is reflected in drier conditions projected along the coast and northeast in the far-future (5th and 50th percentiles), while the eastern half will likely experience increased extreme wet conditions (95th percentile). January projects rainfall increases in the eastern interior, with extreme wet conditions increasing by 35–45 mm across scenarios. Conversely, October may experience increased extreme dry conditions (5th percentile), with more than 48 mm decrease in the far-future under SSP5-8.5. During austral summer (DJF), pronounced wet and dry extremes are projected over eastern South Africa. Austral winter (JJA) will likely experience persistent and intensifying dry and wet extremes along the coast, with the southwest Cape particularly vulnerable to severe dry conditions. Heavy rainfall days are projected to increase in eastern South Africa, exceeding 10 days in the eastern interior. This study is crucial for understanding rainfall extremes under a changing atmospheric circulation and unpins more effective climate change adaptation strategies in South Africa.

Pronounced subsidence leading to summer drought over southern Africa causes warmer than average surface air temperatures or even heatwave (HW) conditions. We investigated the occurrence of HWs during the summer drought over South Africa based on station data and the ECMWF ERA5 reanalyses. Temperature observations from the South African Weather Service were analyzed for seasonality and long-term trends (1981–2020) as background to the occurrence and variability of HWs. We focused on three severe El Niño Southern Oscillation (ENSO)-induced drought seasons, i.e., 1982/83, 1991/92, and 2015/16, to investigate HW characteristics. While 1997/98 was among the strongest El Niño seasons, the impacts were not as severe because it coincided with an intense Angola low, which allowed for rain-bearing cloud bands to form. Results showed that the hottest months were spread across the austral summer season from December to February. Regions experiencing high mean maximum temperatures and high HW frequencies exhibited a strong ENSO signal, with record HWs occurring during 2015/16. The establishment and persistence of a middle-level high-pressure system over Botswana/Namibia (Botswana High) appears to trigger the longest-lasting HWs during drought seasons. The Botswana high is usually coupled with a near-surface continental heat low and/or tropical warm air advection towards the affected region. It was also found that intense ENSO-induced drought events coincided with high HW frequency over South Africa, such as during 1982/83, 1991/92, and the recent 2015/16 events. The results of this study contribute to understanding drought and heat wave dynamics in a region experiencing rapid warming as a result of climate change.