Population heat exposure will increase under climate change . Since AR5 there has been considerable progress with quantifying future human exposure to extreme heat , especially as determined by different combinations of SSPs and RCPs . For example, Table 7.1 shows projections of population exposure to heatwaves, as expressed by the number of person-days, for the 2061-2080 period aggregated by geographical region and SSP/RCP. At the global level, projected future exposure increases from approximately 15 million person-days for the current period to 535 billion person-days for high population growth under the high GHG emission SSP3-RCP8.5 scenario, while for the low population growth/high urbanisation and business as usual SSP5-RCP4.5 scenario, the exposure is substantially lower at 170 billion person- days. Spatial variations in future heatwave frequency and population growth play out in the form of significant geographical contrasts in exposure, with the largest increases projected for low latitude regions such as India and significant portions of sub-Saharan Africa, where increases in heatwave frequency and population are expected. Over East Asia and especially eastern China, exposures are projected to rise, with the effect of increases in heatwave frequency exceeding the countering effect of projected reductions in population, especially in non-urban areas. Further, for North America and Europe, where rural depopulation is projected, the predominant driver of increases in exposure is urban growth .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report