Climate Change, Heat, and Health: Rising Risks and Preventive Actions

Heatwaves and Human Health: A Growing Challenge

Climate change is intensifying heatwaves across the globe, making them longer, hotter, and more frequent. These extreme conditions are no longer rare events—they are becoming a major public health emergency.

Heat stress is now recognized as a leading cause of weather-related deaths. It can worsen chronic illnesses such as cardiovascular disease, diabetes, asthma, and mental health conditions, while also increasing the risk of accidents and infectious disease transmission. Heatstroke, in particular, is a medical emergency with a high fatality rate.

The scale of the problem is alarming. Between 2000 and 2019, an estimated 489,000 heat-related deaths occurred annually, with Asia accounting for 45% and Europe 36%. In Europe alone, the summer of 2022 saw over 61,000 excess deaths linked to heatwaves. Vulnerability is shaped not only by age and health status but also by socio-economic factors, occupation, and housing conditions.

Urban areas are especially at risk due to the urban heat island effect, where poor housing materials and reduced green spaces amplify exposure. Populations with limited access to cooling—such as the urban poor, outdoor workers, and informal settlement residents—face disproportionate risks.

WHO stresses that these impacts are predictable and preventable. Practical interventions include:

• Community-level awareness campaigns to educate people about heat risks.
• Heat action plans and early warning systems to trigger rapid responses.
• Cooling strategies such as shaded areas, ventilation, and affordable access to air conditioning.
• Health worker training to manage surges in admissions during heatwaves.

Simple steps at the household level also save lives: staying hydrated, wearing light clothing, keeping homes cool, and checking in on vulnerable individuals.

Ultimately, mitigating climate change by reducing greenhouse gas emissions remains the most urgent long-term solution. But in the short term, preparedness, awareness, and rapid interventions can significantly reduce heat-related illness and mortality.

This growing challenge underscores the need for multi-sectoral collaboration—from health systems and urban planning to community engagement—to protect populations from the escalating health risks of extreme heat.