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The ongoing global warming is projected to persist throughout the entire century if effective mitigation measures are not put in place. The warming is associated with occurrence of extreme climate events that are prone over Africa. This study uses model data from 24 CMIP6 modeling centers to investigate future changes in extreme climate events over Africa under 1.5 °C, 2.0 °C and 3.0 °C global warming levels (GWLs). The amplified impact in extreme climate events by additional is computed relative to GWL1.5 °C. The models generally simulate observed climate extremes well, with the ensemble mean minimizing data uncertainties. The entire continent is projected to get warmer with the Sahara, Kalahari and parts of the Mediterranean depicting relatively higher temperatures. Both Rx1day and Rx5day are projected to increase over the continent except for the northern and southern regions of the continent. Rx5day is projected to increase by 4–10% for GWL1.5 and GWL3.0 °C. In comparison, an additional 0.5 °C warming between GWL2.0 °C and GWL1.5 °C will lead to an increase of about 43% impact for the climate extremes. An additional GWL1.5 °C (GWL3.0 °C) could result in about 68% increment in climate extremes. The amplified impact of global warming will result in devastating socioeconomic impacts over Africa. This stresses the need of formulating and implementing more ambitious climate change mitigation measures in effort to limit global warming to 1.5 °C. • Future changes in extreme climate are projected over Sahara, Kalahari and parts of the Mediterranean region. • Higher increase in Rx5day compared to Rx1day is projected for GWL1.5 – GWL3.0 °C. • Additional 0.5 °C (GWL1.5 °C) warming will lead to an increase of about 43% (68%) impact for the climate extremes. [ABSTRACT FROM AUTHOR]

• Amplification effects of higher air temperature on the range of changes in flood frequency and magnitude are projected. • Southeast Eurasia, Africa, and South America are hotspots with higher flood defense pressures. • Most watersheds worldwide would face increasing pressures from current flood defense standards in warming climates. Floods usually threaten human lives and cause serious economic losses, which can be more severe with global warming. Therefore, it is a salient challenge to find out how global flood characteristic changes and whether current flood protection standards will face more pressures. This study aims to characterize changes in global floods and explicit flood defense pressures in warming climates of 1.5–3.0 °C above pre-industrial levels by running four well-calibrated lumped hydrological models using bias-corrected Global Climate Model (GCM) simulations for 9045 watersheds worldwide. The results show that global warming from 1.5 to 3.0 °C has increasingly dominated all continents, with amplification effects on changes of flood frequency and magnitude. Southeast Eurasia, Africa, and South America are hotspots of changes for significant proportions of watersheds with larger flood patterns and greater changing extents than others. For example, for the 3.0 °C warming period under the combination of shared socioeconomic pathway 2 and representative concentration pathway 4.5 (SSP245) scenario, the regionally averaged 50-year flood magnitude will increase by 25.6 %, 30.6 %, and 16.4 % for these regions, respectively. The increases in occurrence and magnitude indicate that current flood protection standards will face increasing pressures in future warming climates. The design-level flood frequency is projected to increase for about 47 %, 55 %, 70 %, and 74 % of watersheds in 1.5, 2.0, 2.5, and 3.0 °C warming periods under the SSP245 scenario. However, large uncertainty are observed for the change of flood characteristics dominated by GCMs and their interactions with SSP scenarios and hydrological models. This study implies that the current flood defense standards should be enhanced and climate adaptation and mitigation strategies should be proposed to cope the change of future flood. Floods usually threaten human lives and cause serious economic losses, which can be more severe in the context of global warming. It is a salient challenge to find out how global flood risk changes and whether current flood protection standards will face more pressures. This study aims to characterize changes in global floods and explicit flood defense pressures in warming climates of 1.5, 2.0, 2.5, and 3.0 °C above pre-industrial levels. Here we show that amplification effects of higher air temperature on the range of changes in flood frequency and magnitude are projected. Southeast Eurasia, Africa, and South America are hotspots of changes for significant proportions of watersheds with larger flood patterns and greater changing extents than others. Most watersheds worldwide is likely to face increasing flood defense pressures in warming climates. Our findings could improve the understanding of future flood conditions under the warming climates and provide information to mitigation and adaptation policymaking. [ABSTRACT FROM AUTHOR]