El Niño officially declared by US scientists, threatens extreme weather

The US National Oceanic and Atmospheric Administration (NOAA) has officially declared that El Niño conditions have begun in the tropical Pacific. This natural weather pattern, which raises global temperatures, is characterized by sea surface temperatures that have risen sharply in recent months, exceeding the 0.5°C above average threshold used by US scientists to define an El Niño event.

Many forecasts indicate this El Niño could be particularly strong, possibly among the strongest on record. According to NOAA's June outlook, there is a 63% chance of a very strong El Niño during November-January, ranking among the top three since 1950. Some models suggest temperatures in the tropical Pacific could rise more than 3°C above average by the end of the year.

Coming on top of decades of human-caused warming, this El Niño could lead to another record-hot year, most likely in 2027, with disruptions to weather, food supplies, and economies. The UK Met Office notes that a very strong El Niño typically lifts global air temperatures by about 0.2°C, releasing heat stored in the ocean into an already warming world.

Impacts are most pronounced in the tropics. Flooding is common in northern Peru and southern Ecuador, and can affect parts of East Africa, Central Asia, and the southern United States. Conversely, the risk of drought and wildfire increases across much of Australia, Indonesia, and northern South America, hitting agriculture and global food stocks. El Niño also tends to suppress Atlantic hurricanes, which can lead to less rainfall and potential drought in Central America. In the UK, it may tilt the odds towards a mild start and cold end to winter.

Japan's Meteorological Agency agrees that El Niño conditions are present and expects them to last into autumn. Australia's Bureau of Meteorology has not yet formally declared El Niño but expects it to develop later this year and could be strong.