'Super El Ni帽o' coming? Climate scientists weigh in
Strong El Ni帽o events may bring drought and forest fires to Southeast Asia. (Credit: toa555/Adobe Stock)
On May 14, the National Oceanic and Atmospheric Administration (NOAA) their climate outlook for this summer, and the agency predicted elevated odds of El Ni帽o developing and potentially strengthening later in the year. 听 听
The El Ni帽o-Southern Oscillation, or ENSO, is a natural fluctuation in sea surface temperatures across the tropical Pacific Ocean. Every few years, heat builds up in the Pacific Ocean near the equator, creating warm conditions in the central and eastern part of the basin, a phenomenon known as El Ni帽o. The discharge of this heat into the atmosphere results in colder conditions along the equatorial Pacific, and scientists refer to this pattern as La Ni帽a. 听 听听
Currently, the planet is shifting away from a La Ni帽a that had been in place since last summer to an El Ni帽o. 听 听听
Since the spring, news outlets have been reporting that we will see a "super El Ni帽o" this coming winter. The Washington Post even that this El Ni帽o could be the strongest in a century. 听 听听
探花视频 Today sat down with climate scientists Kris Karnauskas and at the Cooperative Institute for Research and Environmental Sciences (CIRES) to break down these predictions and discuss what is likely to happen this fall and winter. 听 听听
How does El Ni帽o affect our weather? 听 听听
Because the Pacific Ocean is the largest body of water on Earth, when its water gains or loses heat, like during an El Ni帽o or a La Ni帽a event, that can modify atmospheric circulation enough to affect weather conditions in many parts of the world. The warmer the tropical Pacific is, the stronger the El Ni帽o and, generally, its impacts. 听 听听
鈥淓NSO tries to lock us into a weather pattern that persists for several months,鈥 said Karnauskas, who is also an associate professor in the Department of Atmospheric and Oceanic Sciences. 鈥淚t starts with the ocean and has a sort of ripple effect on the weather all over the world.鈥 听 听听
However, El Ni帽o doesn鈥檛 affect weather the same way everywhere. 听 听听
鈥淒uring an El Ni帽o event, we tend to expect a warmer western half of the United States,鈥 Karnauskas said.听
Average location of the Pacific and Polar Jet Streams and typical temperature and precipitation impacts in an El Ni帽os winter over North America. (Credit: Fiona Martin/ NOAA Climate.gov)
The southwestern United States tend to get more precipitation, and the northeastern part of the country could see drier conditions during an El Ni帽o. 听 听听
鈥淚t's not a globally consistent effect. It is very regional,鈥 he added. 听 听听
But for Colorado, these climate patterns may not have a direct impact. It鈥檚 unclear whether the state will see relief from the drought it鈥檚 been battling since last winter. 听 听听
How does an El Ni帽o event develop and how do forecasters track it? 听 听听
The two main ingredients needed to produce an El Ni帽o event are a buildup of warm water in the tropical Pacific Ocean, and changes to winds that can allow that water to reach the typically colder eastern equatorial Pacific and warm that area (El Ni帽o essentially weakens the tradewinds that blow east to west across the equator). 听 听听
Once warm conditions are established in the eastern equatorial Pacific, they can further reinforce the original wind changes, a positive feedback loop that allows the El Ni帽o to grow. 听 听听
El Ni帽o events tend to peak in the Northern Hemisphere鈥檚 winter. During the summer and fall, scientists track the temperature of the Pacific Ocean and the relevant wind conditions to determine whether an El Ni帽o will develop. 听 听听
Right now, we鈥檙e seeing the tropical Pacific Ocean becoming warmer, meaning we鈥檙e trending toward an El Ni帽o, but that doesn鈥檛 necessarily guarantee an El Ni帽o will develop. 听 听 听
Are the current conditions in the Pacific Ocean conducive to producing an El Ni帽o event? 听 听听
The planet has been in a La Ni帽a state for the past few months and are now in neutral ENSO conditions, according to NOAA鈥檚 Climate Prediction Center. However, heat is building in the tropical Pacific Ocean, so scientists are seeing a trend toward El Ni帽o. For the past few weeks, forecast models have been predicting that we will head into an El Ni帽o state later this year and that it could be incredibly strong. 听 听听
Capotondi pointed out that some of the key ingredients for the development of a potentially strong El Ni帽o are in place. The heat content in the equatorial Pacific is large, and strong anomalous winds are present just north of the equator. These winds are associated with another climate fluctuation, the Pacific Meridional Mode, which is in a condition that favors the development of an El Ni帽o. The Pacific Meridional Mode affects the tradewinds and sea surface temperatures in the Pacific Ocean. 听听
鈥淎t this point, we are still relatively early in the year, although we are getting toward the end of spring and things seem to be moving in that direction,鈥 she said. 听 听听
There is also a lot of noise in Earth鈥檚 climate system, Capotondi added, so there is never an absolute certainty that conditions will develop the way they are forecasted to. 听 听听
Should we be concerned that some forecasts are calling for a 鈥榮uper El Ni帽o鈥? 听 听
There鈥檚 no formal, scientific definition of a 鈥榮uper El Ni帽o,鈥 according to Karnauskas. 听 听
鈥淲hat that sounds like to me is a very strong El Ni帽o, and we've had a lot of strong El Ni帽os in the past,鈥 he said. 听 听
Based on the current forecasts, this year鈥檚 El Ni帽o could be the fifth strongest since 1982 when satellites began tracking ocean temperatures, if it continues to develop as predicted.
鈥淪o it wouldn't by any stretch be a record-breaking El Ni帽o,鈥 Karnauskas said. 鈥淏ut it would be a strong one with important implications.鈥 听 听听
This graph shows El Ni帽o and La Ni帽a events since 1982. The strength of the event is related to how far the sea surface temperatures deviate from average. (Credit: Kris Karnauskas and Lauren Lipuma/CIRES/探花视频)
What does all this mean? 听 听听
鈥淭he fuel for a big El Ni帽o is there,鈥 Karnauskas said. 鈥淚t's a question of whether that heat bubbles up to the surface, or if it stays lurking below the surface, out of sight.鈥 听 听听
If El Ni帽o continues to develop the way forecasters predict, it will likely be within the top five strongest El Ni帽os in the past 44 years, according to Karnauskas. We should have a better idea of what the specific impacts will be over the coming months, he added. 听 听听
鈥淚t looks like all the main ingredients are in place for a strong El Ni帽o to occur,鈥 Capotondi said. But it still could turn out weaker than expected. 听 听听
"It is like baking a cake,鈥 she added. 鈥淵ou need all the ingredients, but also a functioning oven for a predictable outcome. We have the main ingredients, and unless the oven breaks, we should have the cake.鈥 听 听
探花视频 Today regularly publishes Q&As on news topics through the lens of scholarly expertise and research/creative work. The responses here reflect the knowledge and interpretations of the expert and should not be considered the university position on the issue. All publication content is subject to edits for clarity, brevity and听university style guidelines.
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