Evidences suggest that the natural El Niño event, a key contributor to global temperature rises and severe worldwide weather disturbances experienced between 2023 and 2024, is hinting at a conclusion, as stated in a recent report from the World Meteorological Organisation (WMO). There is a high probability that the latter portion of the current year will see a shift back towards the colder La Niña conditions in the Pacific Ocean, as forecasted by WMO this Monday. Despite this, parts of the planet are expected to persist in facing the detrimental effects of climate change, including unusually high temperatures, as a consequence of human-triggered climatic changes.
La Niña is the term used to describe significant cooling in surface temperatures of the ocean that occur in the central and eastern equatorial Pacific Ocean. This is accompanied by variations in tropical atmospheric circulation – specifically wind, pressure, and rainfall – causing widespread impacts. With respect to intensity, duration, time of its onset, and its interplay with other climatic variability factors, the effects of each La Niña incident differ. In many regions, predominantly in the tropics, La Niña often results in climate effects that are the exact opposite to those of El Niño.
Nonetheless, these naturally occurring climatic phenomena are now being seen and studied in the backdrop of ongoing climate change. This is causing a consistent rise in global temperature levels, aggravating extreme weather and climate conditions and affecting patterns of seasonal rainfall and temperature, further noted by the WMO.
Ko Barrett, the deputy secretary general of the WMO, commented, “From June 2023 onwards, each successive month set a new temperature record. The year 2023 was the hottest recorded so far. With the demise of El Niño, it does not signify any halt to long-term climate changes. Our earth will persistently heat up as a result of the absorption of heat by greenhouse gases. High sea surface temperatures will have a significant part to play in upcoming months.”
The previous nine years, despite the cooling effects of La Niña that lasted from the year 2020 up to the early part of 2023, have gone down as the hottest till date. Appearing as one of the five most intense ever documented, El Niño reached its zenith in December 2023.
“The escalating severity of our weather is a direct result of the surplus warmth and humidity in our atmosphere. That’s why the Early Warnings for All initiative is a crucial aspect of the World Meteorological Organisation’s (WMO) agenda. We utilise forecasts of El Niño and La Niña, as well as their expected effects on global climatic trends, as strategic tools for prompt warnings and actions,” stated Ms Barrett, the lead of a WMO team at the United Nations climate change deliberations in Bonn this week.
The WMO stated, “Following strong El Niño events, La Niña conditions usually occur. This is consistent with recent predictive modelling, though there is considerable uncertainty about its intensity and term”.
The WMO’s long-range global forecast centres predict a fifty-fifty probability of either neutrality or a La Niña shift occurring from June to August 2024. The likelihood of La Niña conditions augments to 60% between July and September, and further increases to 70% from August to November. During these months, the re-emergence of El Niño is deemed highly unlikely.
However, the most recent worldwide season climate update suggests that above-average sea-surface temperatures will continue to prevail in all regions, with an exception of the near-equatorial eastern Pacific Ocean. A sweeping anticipation of above-average temperatures pervades nearly all terrestrial areas.
Rainfall predictions somewhat align with the usual impacts of La Niña’s early phase, suggesting an increase in rainfall in regions such as the far northern South America, Central America, the Caribbean, the northern Greater Horn of Africa, and the Sahel, southwest Asia, and sections of the central Maritime Continent.
The looming Atlantic hurricane season is projected to exhibit more activity; a conjunction of factors contributes to this, including nearly record-breaking warm sea temperatures in the Atlantic, formation of La Nina circumstances in the Pacific, weakened Atlantic trade winds, and less wind shear,” stated the US National Oceanic and Atmospheric Administration last month.
Updates from the WMO provide crucial assistance to not only governments and the United Nations but also to decision-makers and stakeholders in climate-sensitive sectors, equipping them to prompt necessary measures and safeguard lives and livelihoods.