The powerful El Niño climate pattern brewing in the Pacific Ocean is already influencing extreme weather around the planet. Federal forecasters say it could become the biggest yet, far outpacing any in recorded history and ultimately impacting millions of people.
With that intensity also comes opportunity. Climate experts say studying this El Niño in detail could help them understand the complex phenomenon better, potentially leading to more accurate forecasts to help communities prepare for droughts and floods.
During the last strong El Niño in 2015-16, the National Oceanic and Atmospheric Administration (NOAA) mounted a rapid response research effort to gather observations. The agency sent a research ship, planes, weather balloons and unmanned aircraft into the Pacific to collect data about the atmosphere. After it wrapped up, NOAA staff recommended the agency be ready with a similar effort for the next strong El Niño.
Now, an even stronger El Niño is here, but NOAA will be responding with a scaled-back research effort. The agency is sending a handful of unmanned watercraft to sail into the El Niño zone, but says it won't be matching the field campaign from last time. Any other research projects depend on Congress passing a budget, something that may not happen until December, when El Niño is already peaking.
The Trump administration is also trying to eliminate NOAA's research office, the primary scientific arm that studies events like El Niño, as part of that budget process. Since Trump began his second term, NOAA has lost more than 2,000 staff, largely due to retirements and firings.
Ten weather and climate researchers who spoke with NPR say this record-breaking El Niño is a crucial case study, because aspects of the naturally occurring climate pattern still aren't well-understood. El Niño is one of the biggest forces on the planet affecting weather, bringing destructive rainstorms and floods to some regions, and severe droughts to others. Better and earlier forecast warnings can help communities with emergency response, and even save lives.
Scientists are also trying to understand whether climate change and heat-trapping emissions from burning fossil fuels are making El Niños more intense. A detailed look at how this super El Niño evolves in the ocean and atmosphere could provide valuable data, much like monitoring a patient in the hospital.
"We rarely have opportunities like this," says Daniel Swain, climate scientist with the University of California Agriculture and Natural Resources. "I almost hesitate to call it an opportunity, given that it's likely going to harm a lot of people around the world. But from a scientific perspective, it is a big natural experiment."
Few records of super El Niños
In January 2016, on the small Pacific island of Kiritimati, NOAA began releasing weather balloons twice a day to measure the atmosphere. The island, which is near the equator, was in the heart of an unfolding super El Niño.
El Niño occurs when a vast area of the eastern Pacific Ocean heats up around the equator. That releases huge amounts of heat, sending ripple effects across the atmosphere and shifting weather patterns. In the southern U.S., rainfall typically gets more intense, while the northern half of the country gets drier and warmer.
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El Niños only occur every two to seven years, and super El Niños happen even less frequently, so few of them have been scientifically observed in detail. The first strong El Niño to be measured by satellites from space was in 1982-83, but the data was obscured by a volcanic eruption that spewed particles into the atmosphere.
In 2015, forecasters saw a strong El Niño developing, and researchers at NOAA jumped at the chance to learn from it, because there's less weather data available over the ocean than there is on land.
"You can do research after events are over for years or decades, but you have to get the observations during the event," says Randy Dole, who helped lead the El Niño research campaign at NOAA's Physical Sciences Laboratory and retired in 2016. "That was a critical consideration, and so we were going to do whatever we could, to the best of our ability, to get data that could be used both at that current time and in the future."
Rapid response kicks off
The team began planning six months before field research began. At NOAA, deploying a coordinated campaign in a matter of months was unusual.
"That almost never happens because the big field observation programs are typically five-year planning processes," says Chris Fairall, who worked on the project at NOAA and retired during the Biden administration. "It involves getting research aircraft, research vessels, satellites and all kinds of research plans have to be drawn up."
NOAA's research team found an unexpected opportunity. During El Niño years, there are generally fewer hurricanes in the Atlantic Ocean. NASA had planned research flights in 2016 to observe hurricanes with its Global Hawk, an unmanned long-range aircraft. With less action in the Atlantic, those flights could be redirected to the Pacific Ocean to study the El Niño.
NOAA's team launched the El Niño Rapid Response field campaign.
In addition to weather balloons released from Kiritimati Island, balloons were also sent up eight times per day from a NOAA research ship on a month-long cruise. A NOAA research plane took 22 flights across the Pacific to drop small instruments with parachutes into storms, measuring their formation. The data was also fed to weather forecast models in real time, in the hope of improving winter storm predictions in the U.S.
Ultimately, the 2015-16 El Niño showed how forecasts still have room to improve. California had braced for damaging rainstorms and flooding, but they never materialized. For most of the winter, precipitation was below average in the state. Still, some states saw severe impacts, like catastrophic flooding in South Carolina.
As NOAA's 2016 research campaign wrapped up, the team hoped it would become a blueprint for the next super El Niño, which is now here.
"The recommendation was: let's pre-plan for next time, because there will be a next time," Dole says. "We should be aware that nature's loading the dice for us and exactly what comes up, we don't know."
Challenges at NOAA
As this year's super El Niño approaches its winter peak in November and December, NOAA's research capacity has been in turmoil.
The agency has lost roughly 20% of its staff since Trump began his second term in office, according to data from the U.S. Office of Personnel Management. Some employees were fired, while others took offers for early retirement.
For the second year in a row, the Trump administration is seeking to eliminate NOAA's research arm, the Office of Oceanic and Atmospheric Research, which studies climate patterns like El Niño. The budget proposal "eliminates all funding for climate, weather, and ocean laboratories and cooperative institutes" in the interest of focusing "on NOAA's public safety mission," and would transfer some research to the National Weather Service.
Last year, the Trump administration also tried to eliminate funding for NOAA's research branch. But Congress' budget deal preserved the office for the past year, while transferring some of its budget to the National Weather Service. The administration is also seeking to cut spending on climate change research across NOAA, including programs that "spread baseless environmental alarm," according to the Trump administration.
The Trump administration also announced earlier this year that it would begin removing an ocean monitoring system known as the Ocean Observatories Initiative. It provides key data on sea temperatures, something particularly important during an El Niño. The decision was reversed this summer after pushback from the scientific community.
To study this El Niño, NOAA is deploying four small unmanned watercraft, powered by the wind, known as Saildrones. They'll sail towards the equator, measuring ocean temperatures and other data on a four-month mission.
NOAA is also seeking to do other El Niño-related projects, but the agency says it won't match the resources used in 2016, like planes, ships and other aircraft. In an email, Annarita Mariotti of NOAA's Climate Program Office says the agency is hoping to enhance the observation and prediction of this El Niño with $2 million to $5 million for research. That depends on Congress passing a new budget, which lawmakers have struggled to agree on so far. Currently, the government is operating on a temporary budget measure, known as a continuing resolution, which lasts through Dec. 11.
With this El Niño already close to peaking, NOAA has little lead time to ramp up a research campaign. NOAA's Office of Marine and Aviation Operations, which manages the agency's research ships and planes, says at this time, there are no specific missions planned to study El Niño.
"I'm not super optimistic about anything happening quickly on the federal level these days," says climate scientist Daniel Swain.
Improving weather forecasts
Climate experts say studying El Niños as they happen could help two aspects of forecasting: short-term weather forecasts of El Niño-fueled storms and longer-term forecasts that warn about El Niños as they develop.
Researchers already use aircraft to fly into extreme storms that hit the West Coast, known as atmospheric rivers. These storms produce heavy rain and have caused many of California's most destructive floods.
Satellites provide useful data about weather forming in the Pacific. But researchers at UC San Diego have found that using those detailed readings from planes flying in and near the storms produces a more accurate forecast of where a storm will hit the West Coast and how strong rain will be. That can help communities prepare better for potential flooding.
"We really need the satellite data, but it doesn't give the precision and detail of how strong the atmospheric river is, what its structure is, how much water vapor it's carrying," says Marty Ralph, who works on the project as director of the Center for Western Weather and Water Extremes at UC San Diego's Scripps Institution of Oceanography. "We've proven out that these careful measurements from the aircraft offshore make a big difference for the forecast's skill for the West Coast."
In past years, Ralph's project has partnered with NOAA to gather data on the agency's "hurricane hunter" aircraft. Ralph expects that to continue this winter and is hopeful for as much flight time as possible.
"That is a solid request that's been made, and it's being considered, and it's in a very tight budget environment," Ralph says.
Detailed field measurements more broadly across the Pacific Ocean could also help improve weather forecasting generally, since the weather that forms over the ocean ultimately reaches the U.S.
Warm water that evaporates in the Pacific creates powerful storms, a process known as convection, which can influence weather systems for thousands of miles. Weather models, which use computers to simulate the atmosphere, have struggled to represent that process accurately.
"The models that we've got are decidedly imperfect in their representation of it," Swain says. "So anytime you get a really big signal, it gives a good case to test whether the models are behaving correctly in the real world."
El Niños in a hotter climate
Studying this El Niño could also help scientists understand more about how they form, and ultimately, whether climate change is making them more intense. El Niños are followed by La Niñas, where the tropical Pacific waters cool down, and weather patterns shift again. That transition, driven by the complex interplay between the ocean, wind and atmosphere, is still being studied.
"There's still a lot of uncertainty about how those processes work," says Michael McPhaden, senior scientist at the University of Washington, who was also a NOAA scientist until earlier this year. "We need more examples of well-sampled El Niños to develop a better understanding of how they work and to improve our predictive skill."
Climate change could also be playing a role that's not well-understood. Heat trapped by emissions from burning fossil fuels has already warmed the planet by 1.5 degrees Celsius (2.7 degrees Fahrenheit), and most of that heat has been absorbed by the ocean.
Some studies have found that El Niños are already getting more intense because of climate change. But because of the complexities of El Niño, the computer models that simulate it still need improvement. More detailed case studies of El Niños like this one could help.
"This big event may be connecting the dots for us in a way that is even more compelling about the fingerprint of climate change," McPhaden says.
Given the risk to communities around the world from El Niño-fueled weather impacts, McPhaden says it's a clear example of how field research is valuable for everyday people.
"Field data is irreplaceable," he says. "It's an absolutely essential part of the mix of information that we use to draw conclusions about consequential phenomena like El Niño and La Niña."
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