Extreme Heat Is Already Disrupting School, Work and Health
Excessive heat affects health, learning and work in every region. Humidity, hot nights and unequal access to cooling make the risks worse.
Extreme heat is not only a matter of maximum temperature. Its effects also depend on humidity, the duration of the event, night-time heat and people's ability to protect themselves.
When the body can no longer cool itself
The body releases some of its heat through sweating. When the air is very humid, evaporation becomes less effective. The risk of heat exhaustion and heatstroke rises, particularly for older people, children, those with chronic illnesses and outdoor workers.
Hot nights are especially dangerous because they prevent the body from recovering. Cities often amplify exposure through heat stored in concrete, limited vegetation and poor ventilation in some homes.
Schools and workplaces are directly affected
Excessive temperatures reduce concentration, increase accident risks and can lead to school closures or adjusted working hours. Poorly ventilated classrooms, construction sites, farms and street-based jobs are among the most exposed settings.
Heat is therefore becoming a source of inequality. Households with well-insulated homes, nearby green spaces or access to cooling are better protected than people living in insecure housing or working outdoors.
Prevent rather than react
Heat plans, health alerts, water access, cool spaces and adjusted schedules can quickly reduce risk. Over the longer term, urban vegetation, building insulation, fewer mineral surfaces and shaded public areas strengthen city resilience.
These adaptation measures complement, rather than replace, greenhouse-gas emissions reductions, which are necessary to limit the future intensification of heatwaves.
- Excessive heat affects health, work and learning.
- Humidity, hot nights and poverty increase vulnerability.
- Many effects can be prevented through warnings, planning and protection for exposed people.