“El Niño” soon to return to the South Pacific?

by time news

After four years of absence, he could well be back. According to estimates from the World Meteorological Organization (WMO) released on WednesdayMarch 1, the probability of a reappearance ofThe boy by next August in the South Pacific exceeds 50%. It would cause meteorological disturbances on the Peruvian coasts in particular and an increase in temperatures throughout the globe.

The boy and its pendant The girl correspond to ocean anomalies that modify the temperature of the waters of the equatorial Pacific. Normally, the temperature difference between warm waters in the west and cold waters in the east leads to a difference in atmospheric pressure which favors east-west winds. The warm waters are drawn towards the Asian part of the South Pacific while to the east the deep cold waters rise and cool the surface waters on a long strip along the South American continent.

To the west, the heat accelerates the evaporation of surface water and therefore the transfer of humidity from the ocean to the atmosphere, which causes heavy precipitation and favors the appearance of cyclones. The girl is the name given to the particularly pronounced version of this phenomenon, when surface waters to the east cool more than usual.

An anomaly that recurs every 2 to 7 years

The boy describes the opposite phenomenon. A drop in atmospheric pressure in the South Pacific weakens the east-west winds, or even reverses them. The warm surface waters therefore flow back to the east and bring with them storms and precipitation at the level of the South American coast. The rise in temperature, greater than 1°C, also has consequences for fishing since the fish avoid water that is too hot and poor in nutrients.

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The episodes The boy occur every 2 to 7 years and last between 6 and 18 months. They reach their maximum intensity around Christmas, hence their name (The boy means baby jesus in Spanish). The most recent, low-intensity, took place in April and May 2019.

More The boy can have catastrophic natural consequences over a large geographical area. In 1997, a particularly severe episode caused gigantic fires in Southeast Asia and Australia, heavy rains in California and Central America, and severe drought in Brazil. The average temperature rose all over the globe that year.

General increase in temperatures

On the contrary, the equatorial Pacific has been experiencing a cooling episode since September 2020 The girl of unusually long duration which accentuated the drought in the Horn of Africa and part of South America and caused heavy rainfall in Southeast Asia and Oceania. The phenomenon is coming to an end, according to experts from the World Meteorological Organization. Even if they recall that it is still too early for the forecasts to be completely reliable.

The reappearance ofThe boyif any, will combine its effects with those of global warming. “The cooling effect of The girl temporarily halted the general rise in temperatures, even though the past eight years have been the hottest on record, explains Professor Petteri Taalas, Secretary General of WMO, in his report. If we now enter a phase The boy, we are likely to experience a new peak in global temperatures. » The previous record was reached just after an episode of this type, in 2016. It has a 93% chance of being beaten by 2026, according to the WMO.

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