Fig. 8. (a), (b), (c) Spatial plot of mean summer daytime heatwave duration (HWD) in the 2010s, 2040s, and 2090s. (d), (e) Spatial plot of the differences in the mean summer daytime heatwave duration between the 2040s and 2010s and those between the 2090s and 2010s. All figures correspond to the SSP2-4.5 scenario.
Fig. 9 shows the mean daily maximum 2 m temperature during a heatwave. Blank areas mean that no heatwaves occur in these locations. In the 2010s, when a heatwave occurs in coastal areas, the daily maximum temperature ranges between 33 °C and 34.6 °C, lower than that in the inland areas. In the PRD, Foshan is expected to have the most intense heatwaves with the heatwave intensity reaching 35.9 °C and 36.4 °C in the 2040s and 2090s, respectively. The coastal hotspots in Fig. 9 (e), which display the difference in mean summer daytime heatwave intensity between the 2090s and the 2010s, are primarily caused by several, strong heatwave events that occurred in the 2090s which were rare in the 2010s (Fig. S12–S13). Coastal regions, which may have been accustomed to milder climates, are now more vulnerable to once-in-ten-year heatwaves because of climate warming, despite their proximity to the sea that should have provided some protection.