El Niño Health Alarm: Rising Heat, Floods and Hunger Put Communities on High Alert

The World Health Organization’s new Global Public Health Situation Analysis – El Niño 2026, developed with input from WMO, examines risks by country and region to help health authorities identify where and when support may be needed.

For families living in overheated homes, farmers facing failed rains and communities with limited healthcare, a strengthening El Niño could bring pressures that reach far beyond uncomfortable weather. The World Meteorological Organization (WMO) says the event is forecast to become very strong by the end of 2026, raising the threat of extreme heat, flooding and drought, with consequences for health, livelihoods and economies across the world.

Governments and communities have an opportunity to prepare before those pressures deepen, using climate forecasts to guide health planning and protect people most exposed to danger. Speaking at an Urban Heat Resilience event during the United Nations General Assembly in New York, WMO Secretary-General Celeste Saulo urged governments, health authorities and community organizations to work with meteorological services and treat extreme heat as a predictable public health risk.

Heat Could Leave Cities With Little Relief

El Niño starts with warming in the tropical Pacific, but changes in rainfall and temperature can affect communities thousands of kilometres away, reaching into homes, workplaces, schools and hospitals. Its expected peak late in 2026 will coincide with the approach of the hottest months across much of the Southern Hemisphere, including southern Africa, South America and Australia, increasing concerns about drought, wildfires, smoke and air pollution in early 2027.

Cities can make heat exposure harder to escape because roads and buildings absorb warmth during daylight and release it slowly after sunset, leaving residents with little overnight relief. Older people, children, outdoor workers, people with chronic illnesses and those living in poorly ventilated housing face particular risks, especially when their bodies cannot recover from prolonged exposure.

Extreme heat can directly disrupt the body's functioning and worsen cardiovascular, respiratory, kidney, metabolic and mental health conditions, contributing to severe illness and death. Smoke from wildfires and deteriorating air quality add another layer of danger, increasing the burden of respiratory disease in affected communities.

Floods and Drought Raise Disease and Hunger Risks

The World Health Organization's new Global Public Health Situation Analysis- El Niño 2026, developed with input from WMO, examines risks by country and region to help health authorities identify where and when support may be needed. WMO's seasonal outlook for September to November indicates above-normal rainfall in some regions and drought risks in others, bringing water security, nutrition and mosquito-borne diseases into health preparations.

Warmer conditions and shifting rainfall patterns can increase the spread of malaria, dengue, chikungunya, yellow fever and Zika, potentially exposing communities in higher-altitude areas and other places where these diseases have not traditionally occurred. Strengthened disease surveillance and rapid response will be important as health services track changing patterns of infection and prepare for possible outbreaks.

Malnutrition and cholera are assessed as very high risks in both drought-affected and flood-affected settings, highlighting the dangers facing communities already struggling to secure food and safe water. More than 150 million people are already experiencing acute food insecurity globally, according to the release, and that number is expected to rise as climate shocks disrupt food production and livelihoods.

Early Warnings Need to Reach Health Services

WMO is working with partners to strengthen climate services for health, connecting meteorological specialists with health authorities so forecasts arrive early enough and in formats that support practical decisions. Armel Castellan, Extreme Heat Advisor with the WHO-WMO Climate and Health Joint Programme, stressed that seasonal outlooks give health practitioners valuable time to prepare, with informed decisions potentially making the difference between lives lost and lives saved.

WHO's Teresa Zakaria described El Niño as a public health threat that magnifies existing risks, with the harshest consequences expected where climate shocks meet fragile health systems, poor access to care, food insecurity, displacement and humanitarian crises. Preparation must account for those existing pressures, using warnings to strengthen surveillance, organize rapid responses and reach vulnerable communities before emergencies overwhelm local services.