We are still at the very beginning of an El Niño event. It was determined to have arrived on 4 July this year – which, according to climate researcher Rasmus Benestad at the Meteorological Institute, is unusually early.
– This looks like it will be a strong El Niño, he says and says that the forecasts indicate that it will rise to the levels of the strong El Niños in 2016 and 1998.
He believes that the season forecast has hit well so far.
– The development, the pattern and the way it has built up is somewhat similar to both the one in 2016 and the one in 1998, so the probability is high that this one will also be strong, says Benestad, who explains that an El Niño normally starts in August, and reaches a peak around the New Year.
– But it can last longer, says Benestad, and points out that the previous La Niña lasted a full three years.
Sound the alarm: El Niño has arrived
Reconstruction
In Australia, scientists have now looked more closely at the frequencies of El Niño and La Niña events.
In a new study, published in Naturethe researchers have created a reconstruction of the variations in the Pacific Ocean back to the year 1200.
– This is a statistic we have not had before, and which is probably a little different than expected, says researcher Bjørn Samset at Cicero to Dagbladet.
– Nothing we’ve seen before
– Happens less often
According to associate professor Lea Svendsen at the Bjerknes Center and Department of Geophysics, University of Bergen, the researchers looked at pressure differences in the Pacific Ocean when they prepared the reconstruction.
– There has been a big question mark as to whether the variations are natural or a result of climate change. The conclusions so far are that there are natural variations. At the same time, one sees in the new reconstruction a change after the industrial revolution. It seems that the frequency of El Niño and La Niña has become less and less frequent, says Svendsen to Dagbladet.
– What does that mean?
– This means that the transitions happen less often, and then the chance of multi-year La Niña or El Niños increases. It is a problem because they both affect the weather around the world, replies Svendsen, and points out that in Australia, among other things, they were affected by many floods during La Niña.
She adds that other studies that look at future La Niña or El Niños have concluded the opposite to this study from Australia.
Climate scientists warn
In change
Georgy Falster at ARC Center of Excellence for Climate Extremeswho is one of the researchers behind the study, says the research shows that one of the key drivers of the events is changing, with slower transitions between La Niña and El Niño events.
– This means that in the future we may see more of these multi-year La Niña or El Niño events, as the atmospheric flow over the Pacific alternates more slowly between the La Niña and El Niño phases, says Falster.
– Not good
Researcher Rasmus Benestad is not optimistic about the idea that these events will be able to last any longer.
– It is not so good for us, because both El Niño and La Niña affect the weather systems, where it rains and where there is drought, so if they become more prolonged or intense, it will affect half the globe, says Benestad.
– It remains to be seen how long this El Niño will last, and what consequences it will have, he adds.
2023-08-28 23:42:31
#Reconstructed #Niño #surprises
