The ongoing El Niño event is expected to last at least until April 2024, influencing weather patterns and contributing to a further spike in temperatures both on land and in the ocean, according to a new Update from the World Meteorological Organization.
El Niño, the warm phase of the El Niño/Southern Oscillation (ENSO), is a naturally occurring climate pattern associated with the warming of the ocean surface in the central and eastern tropical Pacific Ocean. It typically occurs every two to seven years and lasts nine to 12 months. However, it’s important to note that this phenomenon takes place within the context of a climate being altered by human activities.
CURRENT STATUS OF EL NIÑO
As of mid-October 2023, sea surface temperatures and other atmospheric and oceanic indicators in the central-eastern tropical Pacific are consistent with El Niño. The event developed rapidly during July-August, reached moderate strength by September 2023, and is likely to peak as a strong event between November 2023 and January 2024. There is a 90% likelihood that it will persist throughout the upcoming northern hemisphere winter and southern hemisphere summer. Based on historical patterns and current long-range predictions, it is anticipated to gradually diminish during the forthcoming boreal spring.
IMPACT ON GLOBAL TEMPERATURE
El Niño’s impacts on global temperature typically manifest in the year following its development, in this case, 2024. However, due to record high land and sea-surface temperatures since June, the year 2023 is now on track to be the warmest year on record. The next year may be even warmer. This is clearly and unequivocally due to the contribution of the increasing concentrations of heat-trapping greenhouse gases from human activities.
EXTREME WEATHER EVENTS
Extreme events such as heat waves, drought, wildfires, heavy rain, and floods will be enhanced in some regions, leading to major impacts. That is why the World Meteorological Organization (WMO) is committed to the Early Warnings For All initiative to save lives and minimize economic losses.
The previous warmest year on record was 2016, due to a “double whammy” of an exceptionally strong El Niño and climate change.
SEA SURFACE TEMPERATURE ANOMALIES
Since May 2023, monthly average sea surface temperature anomalies in the central-eastern equatorial Pacific have warmed significantly, rising from about 0.5 °C above average in May 2023 to around 1.5 °C above average in September 2023. These estimates are relative to the 1991-2020 baseline period.
The most recent forecasts and expert assessment suggest a high likelihood of continued warming in the central-eastern equatorial Pacific for at least the next four overlapping 3-month seasons: November-January, December-February, January-March, and February-April 2024.
EL NIÑO IMPACTS
A strong El Niño does not necessarily mean strong El Niño impacts locally. It is important to note that El Niño is not the only factor that drives global and regional climate patterns, and that the magnitudes of El Niño indicators do not directly correspond to the magnitudes of their effects. No two El Niño events are alike.
GLOBAL SEASONAL CLIMATE UPDATE
Given that ENSO is not the only driver of the Earth’s climate system, the WMO also issues regular Global Seasonal Climate Updates (GSCU), which incorporate influences of other major climate variability modes such as the North Atlantic Oscillation, the Arctic Oscillation, and the Indian Ocean Dipole.