The World Meteorological Organisation (WMO) has confirmed El Niño conditions have developed in the tropical Pacific for the first time in seven years, setting the stage for a likely surge in global temperatures and disruptive weather and climate patterns.
In an update issued on Tuesday the WMO says there is a 90 per cent probability of the El Niño event continuing during the second half of 2023. It is expected to be at least of moderate strength and “will likely fuel further global temperature increase”.
El Niño is a natural phenomenon born out of unusually warm waters in the eastern Pacific and often accompanied by a slowing down or reversal of the easterly trade winds. It also causes warming in the Atlantic, affecting weather and storm patterns.
“The onset of El Niño will greatly increase the likelihood of breaking temperature records and triggering more extreme heat in many parts of the world and in the ocean,” said WMO secretary general Prof Petteri Taalas.
“The declaration of an El Niño...is the signal to governments around the world to mobilise preparations to limit the impacts on our health, our ecosystems and our economies,” he said. “Early warnings and anticipatory action of extreme weather events associated with this major climate phenomenon are vital to save lives and livelihoods.”
El Niño occurs on average every two to seven years, and typically last nine to 12 months. It is a naturally occurring climate pattern associated with warming of ocean surface temperatures. But it takes place in the context of a climate changed by human activities. Its counterpart, the cooling La Niña, has been to fore over recent years.
A WMO report in May predicted a 98 per cent likelihood that at least one of the next five years, and the five-year period as a whole, will be warmest on record, beating the record set in 2016 when there was an exceptionally strong El Niño. It also said there is a 66 per cent likelihood that the annual average near-surface global temperature between 2023 and 2027 will temporarily be more than 1.5 degrees above pre-industrial levels – a critical Paris Agreement limit – for at least one year.
“This is not to say that in the next five years we would exceed the 1.5-degree level specified in the Paris Agreement because that agreement refers to long-term warming over many years,” said WMO director of climate service Prof Chris Hewitt. “However, it is yet another wake up call, or an early warning, that we are not yet going in the right direction to limit the warming to within the targets set in Paris in 2015 designed to substantially reduce the impacts of climate change.”
2016 was the warmest year on record because of the “double whammy” of a powerful El Niño event and human-induced warming from greenhouse gases. The effect on global temperatures usually plays out in the year after its development and so will likely be most apparent in 2024.
El Niño events are typically associated with increased rainfall in parts of South America, the southern US, the Horn of Africa and central Asia. In contrast, it can also cause severe droughts over Australia, Indonesia, parts of southern Asia, Central America and northern South America. El Niño’s warm water can fuel hurricanes in the Pacific, while it could hinder hurricane formation in the Atlantic Basin.
Since February, monthly average sea surface temperature in the Pacific have warmed significantly with an even pronounced warming in the Atlantic near Ireland. “As warmer-than-average sea surface temperatures are generally predicted over oceanic regions, they contribute to widespread prediction of above-normal temperatures over land areas. Without exception, positive temperature anomalies are expected over all land areas in the Northern and Southern Hemisphere,” says the WMO update for July, August and September.
