Heat risk is associated with a range of health issues for urban residents, with the consequences of higher urban temperatures being unevenly distributed across urban populations . Clear evidence exists of increased health risks to elderly populations in settlements, especially higher levels of mortality in elderly populations from urban heat islands during heatwave events , while health and fitness variables are also major determinants of the effects of heat stress  . Heat stress and dehydration are also related to behavioural and learning concerns, with dehydration impairing concentration and cognition for both adults and children . Literature on paediatric heat exposure is associated with increases in emergency department visits for heat-related illnesses, electrolyte imbalances, fever, renal disease and respiratory disease in young children , with less severe outcomes such as lethargy, headaches, rashes, cramps and exhaustion negatively affecting children in school and play environments . Young children in cities are particularly sensitive to heatwaves, and may have little experience or capacity to cope with heat extremes . Such vulnerability of young children to heat is compounded with projected urbanisation rates and poor infrastructure, particularly in South Asian and in African cities . There is evidence that socioeconomically disadvantaged populations are more likely to live in hotter parts of cities associated with higher-density residential land use in dwellings with less effective insulation built with poorer or older construction materials . Specific emerging risks for occupational and related heat illnesses are found in urban tropical or subtropical low- and middle-income countries .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report