Why is this El Niño set to be so strong and what will its effects be in Ireland?

What exactly is El Niño? It’s a naturally occurring climate event that happens every 2-7 years and typically lasts a year.Heat builds up in the waters of the eastern equatorial Pacific – the region stretching roughly between Indonesia and Central America. The heat overspills into adjoining oceans and the air above, becoming dispersed widely around the world in air and sea currents, disrupting weather patterns as it goes. Why is it called El Niño? The name is traced back to South American fishermen in the 17th century who noted it usually peaked in December. They nicknamed it the Spanish for “little boy” as a reference the birth of Jesus. READ MOREWhat kind of disruption does it cause? A key feature is an increase in temperatures almost everywhere in the world – slight in some places but very significant in others. The other main impact is on rainfall. It can cause havoc in places where there are usually very defined periods of rain such as monsoon season, the “wet”, the “dry”, the “big rains” and “small rains”. It can cause prolonged drought or drive severe flooding. Does it have anything to do with climate change? Not by origin. It is recorded long before climate change was identified but the combined effects of El Niño and climate change create double trouble.Why is this one set to be so strong? That’s hard to explain. A lot goes on in the world’s natural climate systems – El Niño is just the best known phenomenon – but other events such as periodic shifts in winds and currents influence each other so El Niño isn’t always so dominating.This one, however, is driven by exceptionally high ocean temperatures – 8 degrees above average in places. What effects can we expect in Ireland? Let’s start with Europe. The prediction is for a hotter, wetter autumn and winter than normal in southern Europe and colder, dryer than normal conditions in northern Europe. Ireland is out in the west where the Atlantic is our main weather influencer, so forecasts are always challenging. However, Met Éireann’s analysis suggests we’re going to fall under the wetter, milder forecast until late autumn at least but possibly through winter. Not the worst, then? Not compared with other parts of the world but it depends just how much wetter it is. Late last year and early this year, the nonstop rain made farming extremely difficult and caused severe flooding.What happens after El Niño? Once it begins to wane – from late spring 2027 – the heat and impacts will take time to dissipate. There then may be a neutral period, called Enso, or a reversal, La Niña, which has a cooling effect around the world.[ ‘Exceptional event’: World braces for ‘supersized’ El NiñoOpens in new window ]