during an El Niño, some of this heat is released to the atmosphere because warm water is spread right across the Pacific, smothering cooler waters. El Niño can add up to 0.2C to annual global surface temperatures.
The El Niño-La Niña cycle switches the position of warm ocean waters and the damp, rain-laden air above it, meaning the cycle brings increased heatwaves, droughts, wildfires and floods to different regions.
The places closest to the Pacific are most strongly affected. In Peru and Ecuador, El Niño brings heavy rains and flooding. The event’s full name – El Niño de Navidad, or the Christ Child – comes from the region and was coined because the biggest impacts occur at Christmas time.
In the Amazon, the weather gets hotter and drier during an El Niño, meaning less growth and greater risk of fires in a forest already approaching a tipping point. Heat and drought also increase in Colombia and Central America.
On the other side of the Pacific, Australia can be hit hard by the higher temperatures brought by El Niño. It raises the risk of heatwaves, drought, and bushfires in the east of the country and also increases the chances of mass coral bleaching of the Great Barrier Reef. The “black summer” of 2019-20 occurred during a small El Niño. Drought risk also increases in Indonesia and the last big El Niño from 2014-2016 fuelled huge forest fires, which sent a smoke plume halfway around the world.
Countries further from the equator are still significantly affected by El Niño, which shifts the position of the high-altitude jet stream wind. As a result, the southern US gets wetter weather and increased flood risks, while the northern US and Canada get warmer and drier. The situation is similar In China, wetter in the south and hotter and drier in the north.