A new El Niño event has officially begun, according to scientists in the United States, sparking warnings of potential extreme weather globally and a likely surge in global temperatures. The US National Oceanic and Atmospheric Administration (NOAA) confirmed that conditions characteristic of El Niño are now present across the tropical Pacific, marked by a notable rise in sea surface temperatures over recent months. This declaration follows the conclusion of its cooler counterpart, La Niña, earlier in the year, a shift that forecasters had largely anticipated.
The intensity of the impending El Niño is a significant concern for researchers. Sea surface temperatures in the central and tropical Pacific have now surpassed the 0.5C above-average threshold used by US scientists to define an El Niño event. Furthermore, NOAA has observed shifts in the winds above the equatorial Pacific, indicating that the atmosphere is now actively responding to the warmer ocean. What has particularly surprised scientists is the high degree of confidence in computer models predicting the strength of this event. Some forecasts suggest this could develop into a 'super' El Niño, potentially ranking among the strongest recorded since 1950, with a 63% chance of a 'very strong' event between November and January, according to NOAA's June outlook.
The implications of a powerful El Niño are magnified by the backdrop of an already warming planet due to climate change. Professor Adam Scaife, head of monthly to decadal prediction at the UK Met Office, emphasised this concern, stating that the current El Niño is 'riding on top of a substantial amount of global warming.' This synergy means that actual temperatures in affected regions could reach unprecedented levels, as the warming influence of El Niño is compounded by ongoing climate change. A very strong El Niño typically contributes around 0.2C to global air temperatures by releasing heat from the ocean into the atmosphere.
Historically, strong El Niño events have been linked to significant global disruption. The three most powerful events since 1950 occurred in 1982/83, 1997/98, and 2015/16. While no two El Niños are identical, their impacts are typically most acutely felt in tropical regions. This can manifest as increased flooding in areas such as northern Peru, southern Ecuador, parts of East Africa, Central Asia, and the southern United States. Conversely, risks of drought and wildfires are elevated across much of Australia, Indonesia, and northern South America, which could have considerable implications for agriculture and global food supplies.
Looking ahead, the combination of this El Niño and existing global warming means that 'at the end of this year and into 2027, we're likely to see very high temperatures globally,' according to Professor Scaife. He added that 2027 could potentially see enough excess heat to push global warming above 1.5 degrees Celsius compared to late-19th-century levels. While NOAA cautions that even strong El Niño events do not guarantee expected impacts everywhere, the increased intensity significantly 'tilts the odds in favour of expected outcomes,' making preparedness crucial.