The onset of El Niño conditions was officially confirmed by the WMO in July. As the weather phenomenon strengthens, it is likely to exacerbate extreme weather events and human health impacts.
Some countries could face increases in droughts, floods or heatwaves, which in turn could affect malnutrition, heat stress, mental illness or risk of vector-borne and waterborne diseases.
What is El Niño and what effects might it produce in different regions? What human impacts are experts anticipating and who will be most affected?
Prof Gregory Wellenius, Professor of Environmental Health at the Boston University School of Public Health (BUSPH) and Director of the BUSPH Center for Climate and Health
Dr Madeleine Thomson, Head of Climate Impacts and Adaptation at Wellcome
Dr Walter Baethgen, Senior Research Scientist in the International Research Institute for Climate and Society (IRI), Climate School, Columbia University
Prof Chris Hewitt, Director of Climate Services at the World Meteorological Organization (WMO)