2016 was the warmest year yet and 2022 is not far behind. Now there are increasing signs of a weather phenomenon that does not bode well in terms of average temperatures.
2022 was one of the warmest years since measurements began in 1850. This is also worrying because it coincided with the cooling effect of the La Niña weather phenomenon. There are growing signs that the three-year La Niña phase, which is unusually long, is coming to an end. Soon the counterpart El Niño could follow, which can also push up temperatures.
The US climate research agency NOAA expected in early January that La Niña would transition into a neutral phase between January and March. “Exceptionally warm deep waters in the tropical western Pacific hint at the next El Niño event in 2023,” climate expert Kevin Trenberth of the University of Auckland wrote in September. This could lead to global temperature records in 2024 – as some of the ocean heat is released into the atmosphere.
New warm phase over the Pacific Ocean
In November, the World Weather Organization (WMO) in Geneva estimated a 25 percent chance that an El Niño phase would begin in the summer. The chance of surpassing the previous record of the warmest year in 2026 is 93 percent. The record year was 2016, with a global average temperature of 1.3 degrees above the level of 1850-1900.
What are La Nina and El Nino? The correct name is “El Niño Southern Oscillation” or “Enso” for short. It describes a coupled ocean-atmosphere circulation system in the tropical Pacific. During the warm El Niño phase, the currents carry sea heat to higher latitudes, some of which ends up in the atmosphere through evaporation.
La Niña is thought to be a cold phase, when currents carry solar heat to the deep waters of the western Pacific Ocean where it is stored. Because fishermen in Peru noticed the warming at the end of the year, they called the phenomenon El Niño (the Christ Child). Between the two extremes, one speaks of a neutral phase.
Temperatures are rising worldwide
According to the WMO, strong and moderate El Niño events contribute to warming and increase the average global surface temperature. “While the strongest effects of El Niño are felt in the equatorial Pacific Ocean, they can affect weather around the world by affecting high and low pressure systems, wind and precipitation,” Columbia University climate researchers explain. “As the warmer ocean water releases excess energy (heat) into the atmosphere, global temperatures are rising.”
WMO chief Petteri Taalas warned in August 2022: “It is very special to have La Niña events in three consecutive years. The cooling effect has temporarily slowed the rise in global temperatures, but this will not stop the long-term warming trend or turn around.”
According to a preliminary forecast, 2022 was one of the warmest years since the beginning of industrialization, despite La Niña. The WMO estimated the global average temperature in November to be about 1.15 degrees above the average from the 1850s to 1900s. In addition, the years 2015 to 2022 were the eight warmest years. (SDA/zis)