Environment
“What goes on in the tropical Pacific doesn’t stay in the tropical Pacific.”
Beachgoers enjoy Kings Beach in Lynn during a hot day in June. Temperatures are expected to be warmer this year than usual due to the “super” El Nino, experts say. David L. Ryan/ Globe Staff
A potentially powerful El Niño is expected to develop in the Pacific Ocean, and forecasters say it could grow into a rare “super” El Niño later this year.
Scientists are still determining just how strong the event may become, as the chances increase for one of the most intense El Niño events on record — a phenomenon that can alter weather patterns across the globe.
In Massachusetts, the impacts are expected to be less dramatic than in tropical or southern regions of the world. Still, climatologists say residents could experience a hotter, more humid summer and a reduced risk of Atlantic hurricanes.
What even is a ‘super’ El Niño?
Occurring roughly every three to seven years, an El Niño is a climate phenomenon in which surface waters in the equatorial Pacific Ocean become significantly warmer than average, according to the U.S. Geological Survey.
A “super” El Niño occurs when those temperatures rise even further.
Christopher Skinner, a professor of atmospheric sciences at UMass Lowell, said waters must warm about 2 degrees Celsius above average for the event to be classified as a “super” El Niño.
A man stands near crashing waves in California in January 2016 during an El Nino event. – AP Photo/Jeff Chiu
Scientists are not yet completely certain a “super” El Niño will develop, Skinner noted, but an El Niño event itself is expected. Researchers will likely know more by June or July.
The last “super” El Niño occurred in 2015-16 and produced one of the warmest winters on record across parts of New England, according to the National Oceanic and Atmospheric Administration. Other “super” El Niños took place 1997-1998, 1982-1983, and 1972-1973.
Some forecasts project Pacific Ocean temperatures could rise close to 3 degrees Celsius above average by late 2026, potentially making it one of the strongest El Niño events on record, according to the Boston Globe.
What are the impacts of a ‘super’ El Niño?
While a temperature increase of a few degrees may not sound dramatic, it is “enough to shift the tropical rain patterns substantially,” said Mathew Barlow, a physical climate scientist and professor at UMass Lowell.
“What goes on in the tropical Pacific doesn’t stay in the tropical Pacific,” he said. “It goes on to influence global weather and climate over the U.S. and over every major continent as well.”
Darker colors in this October 2015 satellite image of the equatorial eastern Pacific indicate the above-normal sea-surface temperatures of a “super” El Niño. – NOAA
The strongest impacts from an El Niño are typically felt in tropical regions. Parts of the Amazon rainforest, southern Africa, and Australia, for example, experience drought conditions during El Niño years, Skinner said, while other regions face heavier rainfall and flooding.
In the U.S., the southern tier of the country — stretching from California to Florida — tends to see wetter-than-average conditions during El Niño events, according to Skinner.
So, how will the ‘super’ El Niño affect Mass.?
Massachusetts does not have as strong a connection to El Niño as other parts of the world, Skinner said.
Experts say the clearest local impacts are typically warmer winters, less snowfall, and more humid conditions.
Summer impacts, however, are generally “fairly muted,” Skinner noted. Massachusetts is still expected to experience above-average warmth and humidity in the summer, which can sometimes contribute to increased precipitation across the Northeast, he said.
One possible benefit: Atlantic hurricane activity often decreases during El Niño years, due to stronger upper-level winds disrupting storm formation.
“Hurricanes tend to get ripped apart during El Niño year, so they don’t really form and certainly don’t make it this far north,” Skinner said. “Of course, it could still happen, but the probability is a bit lower.”
Barlow said the effects in Massachusetts could vary between coastal and inland regions, though the signal may not be strong enough for researchers to confidently predict differences between areas.
“The effect on Massachusetts, most strongly, is indirect rather than direct,” he said, pointing to potential disruptions in agriculture, food systems, and international stability caused by extreme weather elsewhere in the world.
Skinner said New England residents should pay close attention to impacts abroad, especially in regions vulnerable to extreme drought, flooding, and wildfires; disruptions to agriculture and trade can ripple across the global economy.
Residents should also prepare for another hot summer by ensuring access to air conditioning and checking on vulnerable groups, including older adults and young children, Skinner said.
“The advice I would give is similar to any summer because it is getting so much hotter every single year,” he added.
Sea surface temperatures across the Equatorial Pacific Ocean have been warming since the beginning of the year. – Climate Prediction Center
Scientists say many uncertainties still remain
One of the biggest unanswered questions is how a “super” El Niño may interact with human-caused climate change, Barlow said. Because these events occur relatively infrequently, scientists have limited historical data to analyze.
Adding to that, Barlow said cuts to federally funded climate and atmospheric research weakens scientists’ ability to monitor and predict future extreme weather events.
“[It’s] really putting us in a huge deficit to understand these events going forward,” he said. “Now, there are fewer forecasts. There’s fewer data. But we’re also cutting national labs, which reduce our ability to continue to understand these events, particularly as the climate is warming.”
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