Assessing the impact of climate change on future extreme temperature events in major South African cities

In this era of climate change, extreme weather events are expected to become more intense and frequent. This study analysed the long-term future climate data from the mean of five climate model intercomparison project phase 6 (CMIP6) global climate models (GCMs) to examine the impacts of climate change on extreme temperature in four major South African cities. The bias correction was successfully conducted using the CMhyd software program. The analysis of extreme temperatures was conducted using indices developed by the World Meteorological Organization’s Expert Team on Sector-specific Climate Indices (ET-SCI) and calculated using the R-based Climpact2 software. All statistical metrics (mean, R2 and RMSE) show that bias correction was fairly good, and further analysis and conclusions could also be drawn using the adjusted dataset. The overall result shows that annual trends of all temperature indices analysed in this study are significantly increasing for both scenarios (SSP2-4.5 and SSP5-8.5) except for some lower extreme temperature indices (i.e., number of cool days, cold nights and cold spells). In the historical time scale, however, some indices showed no trend for some stations. The study also found that coastal cities had a slower increase in higher extreme weather indices as compared to inland cities. However, for lower extreme indices (such as number of cool days, cold nights, cool day’s temperature and cold spells), the opposite was true. This information is important for policymakers, development agents and disaster prevention workers to make informed decisions about adapting to and mitigating extreme weather events.