The NOAA, the highest scientific authority on climate and oceans in the United States, declared the appearance in the central Pacific of the conditions associated with a new El Niño episode in the first week of June.
The return of this far-reaching climatic phenomenon has now been ratified by the World Meteorological Organization (WMO), according to an official note released this Tuesday, July 4, which details that "El Niño conditions have developed in the Pacific tropical for the first time in seven years, setting the stage for a likely increase in global temperatures and disruptive weather and weather patterns."
A new WMO data update forecasts that there is a 90% chance that El Niño will continue through the second half of 2023, although fortunately, for the time being, it is expected to be at least moderate in strength.
"The occurrence of El Niño will greatly increase the likelihood of breaking temperature records and unleashing more extreme heat in many parts of the world and in the ocean," said WMO Secretary-General Petteri Taalas.
"The declaration of El Niño by the WMO is the signal for governments around the world to mobilize preparations to limit the impacts on our health, our ecosystems and our economies," Petteri details. “Early warnings and anticipatory action for extreme weather events associated with this major climate event are vital to saving lives and livelihoods.”
El Niño occurs on average every two to seven years, and episodes typically last nine to 12 months. It is a naturally occurring weather pattern associated with warming ocean surface temperatures in the central and eastern tropical Pacific Ocean. Experts acknowledge that it is a pattern with thousands of years of existence but warn that its effects may be more radical and unpredictable in a situation of climate change like the current one.
As an indicator of possible situations in the immediate future, the WMO recalls that 2016 is the warmest year on record to date due to the "double whammy" of a very powerful El Niño event and human-induced warming due to greenhouse gases. . The effect on global temperatures typically plays out in the year after its development, and will therefore likely be most apparent in 2024.
The average global temperature in 2022 was about 1.15 °C above the 1850-1900 average due to cooling from the triple dip La Niña.
El Niño events are generally associated with increased precipitation over parts of southern South America, the southern United States, the Horn of Africa, and central Asia.
In contrast, El Niño can also cause severe droughts in Australia, Indonesia, parts of southern Asia, Central America, and northern South America.
During the summer, warm water from El Niño can fuel hurricanes in the central/eastern Pacific Ocean, while it could hinder the formation of hurricanes in the Atlantic basin.
In general, El Niño has the opposite effect of the recent La Niña, which ended in early 2023.
Since February 2023, monthly mean sea surface temperature anomalies in the east-central equatorial Pacific have warmed significantly, from almost half a degree Celsius below average (-0.44 in February 2023) to about half a degree Celsius above average (0.47 in May 2023). In the week centered on June 14, 2023, warm sea surface temperature anomalies have continued to increase, reaching a value of 0.9 degrees Celsius.
The collective evidence from oceanic and atmospheric observations strongly points to the presence of El Niño conditions in the Pacific. However, some uncertainty remains due to the weak ocean-atmosphere coupling, which is crucial for the amplification and sustenance of El Niño. It is anticipated that it will take another month or so to witness a fully established mating in the tropical Pacific.
