How cities can protect people from extreme heat
- Editorial Team SDG11
- 1 day ago
- 5 min read
Published on 1 September 2026 at 05:11 GMT
By Editorial Team SDG11
Prolonged heatwaves turn an environmental hazard into a city-wide test of health services, housing, labour protection and public space. Heat exhaustion and heatstroke are immediate dangers, while high temperatures can aggravate cardiovascular, respiratory, kidney and mental-health conditions. The World Health Organization identifies older people, infants, outdoor workers, people with chronic illness and those with limited resources or inadequate housing among the groups facing increased risk.
The exposure is unequal. Older people may regulate body temperature less effectively, take medicines that alter hydration or live alone without help. Infants and young children depend on adults to recognise symptoms and provide water and cooling. UNICEF reported in 2024 that 466 million children lived in areas experiencing at least twice as many days above 35 °C as in the 1960s, based on a comparison with the 2020-2024 average.
For people in poorly insulated homes, danger may continue after outdoor temperatures fall. Upper-floor flats, metal roofs, limited ventilation and dense neighbourhoods with little vegetation can retain heat. Tenants and low-income households may have less control over building improvements and less capacity to pay for air conditioning or the electricity it consumes. Power demand can rise at the same time as heat places pressure on electricity, water, transport and health systems.
Heat also carries economic costs. Outdoor and manual workers face illness and injury when physical exertion adds metabolic heat to hot, humid conditions. Slower work, altered hours and stoppages affect earnings and output, while employers and public services absorb costs associated with absence, treatment and disrupted operations. The International Labour Organization says excessive occupational heat can cause heat exhaustion, heatstroke and death, and is associated over time with cardiovascular, respiratory and kidney disease.
No single heat measure covers every risk. City authorities therefore face a choice about the balance between interventions that reduce temperatures over years and services that protect people during an emergency.
Trees and shaded streets can lower exposure for pedestrians, public-transport users, street vendors and other outdoor workers. Tree canopies intercept sunlight and cool the air through evapotranspiration, while awnings, arcades and shelters provide shade sooner and in places where planting is difficult. Trees require suitable species, soil, water and maintenance, and their benefits take time to mature. Poorly planned planting can also compete with utilities or fail during drought. The World Bank, with contributions from UN-Habitat and the United Nations Environment Programme, presents green infrastructure as one part of a wider urban heat strategy rather than a stand-alone response.
Cool roofs use light-coloured or reflective surfaces to absorb less solar energy. They can reduce heat entering buildings and are particularly relevant where roofs receive intense sun and mechanical cooling is limited or costly. Their effect is concentrated on buildings rather than pavements and workplaces across the wider city. Performance varies with climate, roof condition, materials and maintenance, and retrofits depend on ownership, finance and building standards. Insulation, external shading, ventilation and reflective roofs address different parts of indoor overheating, so a poorly insulated home may require a package rather than a single coating.
Cooling centres provide an immediate refuge during dangerous conditions, especially for residents without safe indoor temperatures. Libraries, community buildings and other accessible facilities can be designated for this role. Their protective value depends on opening hours, transport, disability access, staffing, drinking water, backup power and public confidence. A centre that is distant, unknown or difficult to reach may not serve an isolated older resident or a worker unable to leave a shift.
Heat-warning systems can convert forecasts into health-relevant alerts and trigger pre-agreed action. WHO Europe's 2026 guidance identifies eight core elements of a heat-health action plan: governance; a heat-health warning system; populations at increased risk; communication; health-system resilience; reducing heat exposure; heat-health surveillance; and monitoring, evaluation and learning. Alerts can prompt welfare checks, extended centre hours, changes to school or work schedules and preparation by hospitals. Their reach is limited when messages are not available in relevant languages, do not reach people without digital access or are issued without a funded response.
Workplace rules address a different gap because personal choice may be constrained by pay, supervision and deadlines. The ILO's review of heat-stress legislation in 21 countries found that 57 per cent of the legislation analysed included rest breaks or modified schedules, 67 per cent included hydration provisions and 33 per cent required cool, shaded or ventilated rest areas. These figures describe the legislation reviewed, not global coverage. Legally protected rest periods can give workers enforceable time away from exposure, while schedule changes can move heavy labour outside the hottest hours. Their effect depends on temperature or heat-stress thresholds, paid status, enforcement, worker coverage and protection against retaliation.
The measures also operate on different timescales. Warnings and cooling centres can be activated before and during a heatwave. Worker protections can change exposure during a shift but require inspection and enforcement. Roof retrofits can improve a building relatively quickly, while a healthy urban canopy may take years. Air conditioning can reduce indoor exposure, but high costs, unreliable electricity and waste heat can reinforce inequality or strain the grid if it becomes the principal response.
WHO guidance frames heat-health action as a coordinated portfolio with clear triggers, accountable roles, resources and monitoring. That approach connects public-health agencies with meteorological services, housing authorities, employers, schools, transport operators and community organisations. Local heat mapping and health data can identify streets and households where exposure and vulnerability overlap, although surveillance requires safeguards for privacy and for residents who may be missed by official datasets.
The issue is closely connected to SDG 11 (sustainable cities and communities) because housing quality, public space, transport access and disaster preparedness shape who can escape dangerous heat. The central policy question is not whether trees, roofs, centres, warnings or labour rules compete for one universal solution. It is how cities combine them so that emergency protection reaches people now while buildings and neighbourhoods become less hazardous over time.
Written by a human author, edited with AI assistance.
Further information:
● World Health Organization Regional Office for Europe, Heat-health action plans: guidance, second edition, supports the description of risk groups and the components of coordinated heat-health planning.
● World Bank, Handbook on Urban Heat Management in the Global South, supports the comparison of green infrastructure, passive cooling and wider urban heat-management measures.
● International Labour Organization, Heat at work: Implications for safety and health, supports the occupational-health effects and analysis of heat-stress legislation in 21 countries.
● UNICEF, Almost half a billion children live in areas experiencing at least twice as many extremely hot days as their grandparents, supports the estimate of children's changing exposure to days above 35 °C.
● World Meteorological Organization, Extreme Heat, supports the role of impact-based early warnings and the unequal distribution of heat risk.
