El Niño Event

The current El Niño event was first declared in June 2023. The past months have already demonstrated that several of the predicted weather-related risks and attendant health consequences associated with El Niño have already come to pass in multiple settings around the globe (with the caveat that any climate-related event is multifactorial and thus difficult to attribute specifically to El Niño).

El Niño conditions increase the probability of a range of extreme weather events, including droughts, floods, hurricanes, and heatwaves, all of which are detrimental to human health. The magnitude of health impacts associated with El Niño will vary depending on how intensely El Niño influences the local climate of an area as well as local health vulnerabilities, and preparedness and response capacities. Health consequences associated with extreme weather conditions are interrelated, and can occur as a result of a range of factors:

• Both droughts and flooding may trigger food insecurity, increase malnutrition and thus enhance vulnerability to infectious diseases;
• Droughts, flooding and intense rainfall (including cyclones) may cause loss of life, significant population displacement, water and vector-borne disease outbreaks, and damage or close health facilities, thus reducing access to healthcare during the emergency and well beyond the event;
• El Niño-related warmer temperatures may result in vector-borne disease epidemics in highland areas, which are too cold for vector survival and disease transmission at other times;
• Damaged or flooded sanitation infrastructure may lead to water-borne diseases;
• Extremely hot and dry conditions may lead to heat waves, wildfires, increased smoke and deteriorated air quality, causing or exacerbating respiratory diseases and heat stress;
• Populations already affected by a humanitarian crisis (e.g. those in internally displaced persons and refugee camps) face heightened risk of the health consequences of both wet and dry.