Europe 1 with AFP / Photo credits: JUAN JOSE HORTA / AFP 16:15 pm, May 03, 2023

The UN warned on Wednesday that the El Nino weather phenomenon is likely to form this year and could push temperatures up to new heat records. "This will change weather and climate conditions around the world," the organization said.

The El Nino weather phenomenon is likely to form this year and could push temperatures up to breaking new heat records, the UN warned Wednesday. The World Meteorological Organization (WMO) now estimates that there was a 60% chance of El Nino developing by the end of July and an 80% chance by the end of September.

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El Nino last performed in 2018-2019

"This will change weather and climate patterns around the world," Wilfran Moufouma Okia, head of WMO's Regional Climate Prediction Services Division, told a news conference in Geneva. El Nino, is a natural climatic phenomenon generally associated with rising temperatures, increased drought in some parts of the world and heavy rains in others.

It last occurred in 2018-2019 and gave way to a particularly long episode of La Nina, which causes the opposite effects and in particular a drop in temperatures. Despite this moderating effect, the past eight years have been the warmest on record. Without La Nina, the warming situation could have been even worse.

It "acted as a temporary brake on the rise in global temperature," WMO chief Petteri Taalas said in a statement. "The development of El Nino will most likely lead to a new peak in global warming and increase the chances of breaking temperature records," he warned.

Effects on temperatures are felt the following year in general

At this stage, it is not possible to predict the intensity or duration of the looming El Nino. The last one was considered weak, but the one before, between 2014 and 2016, was powerful and it had disastrous consequences. The WMO pointed out that 2016 was "the hottest year on record due to the 'double effect' of a very powerful El Nino and warming caused by human-related greenhouse gases."

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The effects of El Nino on temperatures are generally felt the year after the emergence of the weather phenomenon, its impact will probably be felt more in 2024, says the WMO. "We expect, in the next two years, a sharp increase in global temperatures," said Wilfran Moufouma Okia. "The world must prepare for the development of El Nino," the WMO chief warned.

This "could bring respite from drought in the Horn of Africa and other impacts related to La Nina, but could also trigger more extreme weather and climate events," he said. He stressed the need for early warning systems - one of WMO's priorities - to protect the most threatened populations.

Rising precipitation in southern South America

No two El Ninos are the same and their effects depend in part on the time of year, WMO said, adding that it and the national meteorological services would closely monitor developments in the next announced event. The phenomenon occurs on average every two to seven years and usually lasts nine to 12 months. It is generally associated with warming ocean surface temperatures in the central and eastern tropical Pacific Ocean.

El Nino typically causes increased rainfall in parts of southern South America, the southern United States, the Horn of Africa and Central Asia, while El Nino can cause severe droughts in Australia, Indonesia and parts of South Asia.

During the boreal summer - the warm season in the northern hemisphere and cold in the southern hemisphere - the warming of surface waters caused by El Nino can also fuel hurricanes in the central and eastern Pacific Ocean, while preventing the formation of hurricanes in the Atlantic basin, the WMO explained.