The growing effect of CO2 and other greenhouse-gas (GHG) emissions on the extreme climate risks in the Western Cape, South Africa, calls for the need for better climate adaptation and emissions-reduction strategies to protect region’s long-term social-economic benefits. This paper presents a comprehensive evaluation of changes in the future extreme events associated with drought and heatwave under three different greenhouse gases (GHG) emissions scenarios: Representative Concentration Pathway (RCP) 2.6, RCP 4.5, and RCP 8.5, from moderate to severe, respectively. A variety of diagnostic indices are used to determine how future heatwaves and drought will response to each different RCP climate scenario in Western Cape based on Max Planck Institute-Earth System Model/REMO (MPI-ESM/REMO). The projected simulation results reveal that both drought-related and heatwave-related extreme climate indices suggest very strong relationships between the future extreme climate risks and the GHG emissions for Western Cape, South Africa. Anthropogenic activities and growing GHG emissions will lead to severer extreme climate stress in terms of drought as well as duration, frequency, and magnitude of heatwave stresses. As a result, we believe that reducing the GHG emissions to alleviate future extreme climate stress becomes a practical solution to protect the local’s socio-economic system and further maintain the region’s economic prosperity.