Scientists forecast an 80 percent likelihood that an El Niño will form by September, with most models pointing to a moderate event. Some simulations indicate the possibility of a much stronger episode. Global warming is expected to intensify the effects of any such occurrence.
The El Niño phenomenon involves shifts in Pacific Ocean winds and waters that can alter weather patterns worldwide. An event occurs when sea-surface temperatures in the central and eastern Pacific rise more than 0.5 degrees Celsius above average. Historical strong episodes in 1982-83, 1997-98 and 2015-16 caused widespread damage including coral die-offs and economic losses reaching trillions of dollars. Axel Timmermann of Pusan National University noted that future events of similar strength will produce larger regional impacts because the world is warmer. Richard Allan of the University of Reading said increased atmospheric moisture will make floods more intense while droughts last longer due to faster soil drying. Models from Timmermann's team also project stronger swings between El Niño and La Niña phases that could begin affecting weather in Europe and the Atlantic. Adam Scaife of the Met Office Hadley Centre stated there remains disagreement among climate models on whether El Niños themselves will intensify. The current warming trend is projected to continue amplifying effects at least until after 2150.