'Super El Ni簽o' coming? Climate scientists weigh in
Strong El Ni簽o events may bring drought and forest fires to Southeast Asia. (Credit: toa555/Adobe Stock)
Editor's Note: This story was updated on June 12 to reflect the latest NOAA predictions and new research results.
On June 11, the National Oceanic and Atmospheric Administration (NOAA) confirmed that El Ni簽o has developed in the tropical Pacific. Scientists predicted that this weather condition has a 63% chance of intensifying into a very strong El Ni簽o this fall and winter.泭
The El Ni簽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簽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簽a.泭泭
Currently, the planet is shifting away from a La Ni簽a that had been in place since last summer to an El Ni簽o.泭泭泭
According to a泭 by researchers at NOAA and the Cooperative Institute for Research and Environmental Sciences (CIRES) at CU 勒貊勛圖, the likelihood of extensive wildfire developing in the Southwest and Rocky Mountain regions during the spring and summer following an El Ni簽o in the fall would be halved.
El Ni簽o doesnt affect weather the same way everywhere, according to CIRES climate scientists泭Kris Karnauskas and. For Colorado, these climate patterns may not have a direct impact. Its unclear whether the state will see relief from the drought its been battling since last winter, Karnauskas said.泭泭泭泭泭泭
CU 勒貊勛圖 Today sat down with Karnauskas and Capotondi to break down these predictions and discuss what is likely to happen this fall and winter.泭泭泭泭泭
How does El Ni簽o affect our weather? 泭 泭泭
Because the Pacific Ocean is the largest body of water on Earth, when its water gains or loses heat, like during an El Ni簽o or a La Ni簽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簽o and, generally, its impacts. 泭 泭泭
ENSO tries to lock us into a weather pattern that persists for several months, said Karnauskas, who is also an associate professor in the Department of Atmospheric and Oceanic Sciences. It starts with the ocean and has a sort of ripple effect on the weather all over the world. 泭 泭泭
However, El Ni簽o doesnt affect weather the same way everywhere. 泭 泭泭
During an El Ni簽o event, we tend to expect a warmer western half of the United States, Karnauskas said.泭
Average location of the Pacific and Polar Jet Streams and typical temperature and precipitation impacts in an El Ni簽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簽o. 泭 泭泭
It's not a globally consistent effect. It is very regional, he added. 泭 泭泭
How does an El Ni簽o event develop and how do forecasters track it? 泭 泭泭
The two main ingredients needed to produce an El Ni簽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簽o essentially weakens the tradewinds that blow east to west across the equator). 泭 泭泭
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簽o to grow. 泭 泭泭
El Ni簽o events tend to peak in the Northern Hemispheres 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簽o will develop. 泭 泭泭
Right now, were seeing the tropical Pacific Ocean becoming warmer, meaning were trending toward an El Ni簽o, but that doesnt necessarily guarantee an El Ni簽o will develop. 泭 泭 泭
Are the current conditions in the Pacific Ocean conducive to producing an El Ni簽o event? 泭 泭泭
The planet has been in a La Ni簽a state for the past few months and are now in neutral ENSO conditions, according to NOAAs Climate Prediction Center. However, heat is building in the tropical Pacific Ocean, so scientists are seeing a trend toward El Ni簽o. For the past few weeks, forecast models have been predicting that we will head into an El Ni簽o state later this year and that it could be incredibly strong. 泭 泭泭
Capotondi pointed out that some of the key ingredients for the development of a potentially strong El Ni簽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簽o. The Pacific Meridional Mode affects the tradewinds and sea surface temperatures in the Pacific Ocean. 泭泭
At 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, she said. 泭 泭泭
There is also a lot of noise in Earths climate system, Capotondi added, so there is never an absolute certainty that conditions will develop the way they are forecasted to. 泭 泭泭
Should we be concerned that some forecasts are calling for a super El Ni簽o? 泭 泭
Theres no formal, scientific definition of a super El Ni簽o, according to Karnauskas. 泭 泭
What that sounds like to me is a very strong El Ni簽o, and we've had a lot of strong El Ni簽os in the past, he said. 泭 泭
Based on the current forecasts, this years El Ni簽o could be the fifth strongest since 1982 when satellites began tracking ocean temperatures, if it continues to develop as predicted.
So it wouldn't by any stretch be a record-breaking El Ni簽o, Karnauskas said. But it would be a strong one with important implications. 泭 泭泭
This graph shows El Ni簽o and La Ni簽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/CU 勒貊勛圖)
What does all this mean? 泭 泭泭
The fuel for a big El Ni簽o is there, Karnauskas said. It's a question of whether that heat bubbles up to the surface, or if it stays lurking below the surface, out of sight. 泭 泭泭
If El Ni簽o continues to develop the way forecasters predict, it will likely be within the top five strongest El Ni簽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. 泭 泭泭
It looks like all the main ingredients are in place for a strong El Ni簽o to occur, Capotondi said. But it still could turn out weaker than expected. 泭 泭泭
"It is like baking a cake, she added. You 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. 泭 泭
CU 勒貊勛圖 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泭university style guidelines.
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