The latest data from the World Meteorological Organization shows that the La Niña event that has lasted for a long time is likely to continue until the end of this year or longer. This will be the first time in the 21st century that a "triple" La Niña event will occur, that is, three consecutive La Niña winters in the northern hemisphere.
So what does a possible "triple" La Niña this winter mean?
The so-called La Niña event refers to the phenomenon that the sea surface temperature in the eastern and central equatorial Pacific continues to be abnormally cold.
The World Meteorological Organization's August forecast shows that the current La Niña event is likely to continue for the next six months, with a 70% chance of lasting until September-November 2022, and a probability of lasting until December 2022-February 2023 will gradually decrease to 55%.
The current La Niña event began in September 2020, and as trade winds strengthened from mid-July to mid-August 2022, La Niña event conditions in the tropical Pacific have intensified, affecting temperature and precipitation patterns, exacerbating drought and drought in different parts of the world. flood.
La Niña and El Niño events generally occur every two to seven years, with neutral years in between.
The El Niño event is a climate event caused by an abnormal increase in seawater temperature in the central and eastern equator of the Pacific Ocean, while the La Niña event is the opposite, which refers to the continuous period of time in which the sea temperature in the region is lower than the normal year temperature.
If El Niño events are strong, they could lead to subsequent La Niña events lasting two or even three years.
Two consecutive La Niña winters are common in the Northern Hemisphere, but three in a row are rare.
The three-year "triple" La Niña has occurred only twice since 1950.
But the difference is that the "triple" La Niña events that may occur this winter are not after a strong El Niño event.
The impact of each La Niña event varies, depending on the intensity of the event, the timing of its development, and interactions with other climate patterns.
WMO Secretary-General Petri Taalas said in the recent La Niña Forecast Bulletin: "The worsening drought in the Horn of Africa and southern South America has the characteristics of a La Niña event, with exceptional rainfall in South-East Asia and Australasia. The same goes for the volume. The latest La Niña event unfortunately confirms regional climate predictions that a devastating drought in the Horn of Africa will worsen and affect millions.”
The British "Nature" magazine issued a warning in June that more La Niña events will have multiple impacts, such as increasing the probability of floods in Southeast Asia, increasing the risk of drought and wildfires in the southwestern United States, and forming multiple types in the Pacific and Atlantic. Hurricane, cyclone, and monsoon patterns, and changes in weather that trigger other regions.
The World Meteorological Organization says El Niño and La Niña events are important drivers of Earth's climate system, but not the only ones.
Despite the persistence of a La Niña event in the central and eastern equatorial Pacific, generally above-average sea surface temperatures are estimated elsewhere in September-November, which will lead to above-normal temperatures over land, including many parts of the Northern Hemisphere.
Taalas said: "The three-year La Niña event is special. The cooling effect it brings temporarily slows the rise of global temperature, but it will not prevent or reverse the long-term trend of global warming." (Source: CCTV News) client)