773. El Niño Phenomenon Outlook for 2023

On May 3, the World Meteorological Organization (WMO) released its outlook for the possible increasing impact of an El Niño event later this year. The El Niño event has the potential to push global temperatures even higher, with an impact that contrasts with the weather and climate patterns that La Niña has brought in recent years.

After three years of unprecedented and persistent La Niña, the tropical Pacific Ocean is now in an ENSO-neutral state that is neither El Niño nor La Niña. The WMO has announced that the probability of a transition from this normal state to El Niño in May-June 2023 is 60%, rising to 70% in July-August and 80% in July-September.

Despite a La Niña event for the past three years, the past eight years have been consecutive years of high temperatures. The developing El Niño phenomenon means that the possibility of breaking the record for the hottest global temperatures is on the horizon. In fact, the hottest temperature ever recorded in 2016 was attributed to a "double whammy" of a very strong El Niño event and anthropogenic warming from greenhouse gases.

La Niña events typically have the effect of slowing the rise in global temperatures, while El Niño events have brought higher temperatures and, in some areas, drought and heavy rainfall. In the past, regions such as southern South America, the southern United States, the Horn of Africa, and Central Asia have experienced significant increases in precipitation during El Niño events, while Australia, Indonesia, and South Asia have experienced droughts. During the Northern Hemisphere summer, warm El Niño waters tended to bring hurricanes to the central and eastern Pacific, but prevented the formation of hurricanes in the Atlantic. On the other hand, no El Niño event has ever produced a similar event, and it is known that the effects can vary depending on the timing during the year.

Contributor: IIYAMA Miyuki (Information Program)