El Niño is "strengthening rapidly" just weeks before its anticipated peak in December, according to experts, increasing the chances of a weather event previously linked to the notorious Beast from the East.
What is El Niño?
El Niño is a climate phenomenon that occurs every two to seven years when temperatures in the tropical eastern Pacific climb 0.5C above average, influencing weather patterns across the globe. It can heighten the likelihood of cold snaps in late winter in north-west Europe, including the UK.
The World Meteorological Organization (WMO) said in its most recent update that sea-surface temperatures in the central and eastern tropical Pacific are expected to surge to "record levels" in October, November and December, "reflecting the strengthening of the El Niño event".
Polar vortex breakdown risk
Following its peak, El Niño "tends to promote the breakdown of the polar vortex, especially in late winter", according to the US government's NOAA Chemical Sciences Laboratory. The weakening of the polar vortex - a band of strong westerly winds surrounding a pool of cold air high in the stratosphere - "may raise the chance of Sudden Stratospheric Warming events, which can increase the potential for cold weather", the Met Office warns.
The national weather service previously said that several extreme cold and winter snow events have been linked to the effects of sudden stratospheric warmings, including those in 2009-10 and 2013, as well as the notorious "Beast from the East" in 2018. The so-called "Big Freeze of 2010", which saw the winter of 2009-10 become the coldest in three decades at the time, also coincided with an El Niño event.
Record-breaking forecast
WMO Secretary-General Celeste Saulo said: "El Niño is firmly established and strengthening rapidly. WMO forecasts indicate a near-100 per cent likelihood that it will persist through February 2027, potentially being one of the strongest since at least 1950."
She explained that the near-certainty figure reflects a consensus amongst 13 national and international centres - from Washington to Tokyo to London to Pune - built on real-time exchange of ocean buoy, satellite and radiosonde data. For October, November and December, the seasonal average sea-surface temperature anomaly is predicted to reach approximately +3.7C, hitting its peak around December. This would represent the highest figure ever recorded, eclipsing the previous record of +2.6C, which was set between November 2015 and January 2016.
Global temperature impact
Strong El Niño events are typically associated with a rise in global average temperatures, as additional heat released from the ocean into the atmosphere spreads around the globe, further warming other ocean basins, the Met Office explains. Exceptionally strong El Niño events can therefore play a role in record-breaking global temperatures in the year after they reach their peak.
The current event is unfolding against a backdrop of long-term human-induced climate change, which means its effects are layered on top of an already warming climate, according to the Met Office.
