Physiological Heat Survivability in Southeast Asia Projected under Different Socio-economic Pathways

Increasing temperatures and humidity driven by accelerating global warming have posed significant health risks that threaten human survivability. Southeast Asia is expected to be especially vulnerable due to its limited capacity to mitigate extreme heat exposure. In this study, we assess future risks to heat survivability projected under different socio-economic pathways, utilizing physiology-based survival limits that consider physiological and biophysical principles for younger and older adults under shaded indoor or sun-exposed conditions. Detailed future climate conditions in Southeast Asia are projected using a dynamical downscaling approach with a regional climate model driven by bias-corrected global climate model outputs under different emission scenarios realized by plausible socio-economic pathways. The analysis primarily focuses on understanding the role of humidity in physiological heat stress through an in-depth examination of how different combinations of air temperature and relative humidity impact heat survivability. Additionally, this study presents a comparative assessment of heat survivability projections under varying global warming levels. These findings could provide valuable insights into the benefits of climate change mitigation and help identify regional hot spots. [Acknowledgements] This research was supported by the Theme-based Research Scheme, T31-603/21-N, which was funded by the Research Grants Council (RGC) of Hong Kong.