Enviro News Asia, Geneva — The World Health Organization (WHO) has warned that extreme heat is becoming one of the most serious environmental and occupational health threats, with climate change driving more frequent, longer, and more intense heatwaves worldwide.
According to WHO, heat exposure is a leading cause of weather-related deaths and can worsen a wide range of health conditions, including cardiovascular disease, diabetes, respiratory illnesses, asthma, kidney disease, and mental health disorders. Heatstroke remains a medical emergency with a high fatality rate if not treated promptly.
WHO estimates that approximately 489,000 heat-related deaths occurred annually between 2000 and 2019, with Asia accounting for 45% of those fatalities and Europe for 36%. Heat-related mortality among people aged over 65 increased by about 85% between 2000–2004 and 2017–2021, reflecting the growing impact of climate change on vulnerable populations.
The agency said climate change is increasing the frequency and intensity of heatwaves, creating cumulative stress on the human body and raising the risks of illness, death, reduced labor productivity, and disruptions to health services, transportation, and water infrastructure. Older adults, people with chronic diseases, outdoor workers, low-income communities, and residents of densely populated urban areas are among the groups most vulnerable to extreme heat.
WHO explained that excessive heat affects the body’s ability to regulate internal temperature, increasing the risk of heat exhaustion and heatstroke while placing additional strain on the heart and kidneys. Extreme temperatures can also worsen chronic illnesses and increase hospital admissions during heatwave events.
To reduce health risks, WHO advises people to avoid strenuous outdoor activities during the hottest hours of the day, remain in shaded or cool environments, stay well hydrated, wear lightweight clothing, and regularly check on elderly people and those with underlying health conditions. The agency also urges parents never to leave children or animals inside parked vehicles and recommends measures to keep homes cool during periods of extreme heat.
WHO said reducing greenhouse gas emissions remains essential to limiting the long-term health impacts of extreme heat. The organization continues to support governments through heat action plans, early warning systems, emergency preparedness, and international initiatives such as the Alliance for Transformational Action on Climate and Health (ATACH), the Global Heat Health Information Network, and the “Beat the Heat” campaign to strengthen resilience against rising temperatures. (*)
