Hurricane Polo Study: Climate Change Beat El Niño

A new Hurricane Polo study just settled a debate that has been simmering all season: what made the Pacific's most stubborn monster storm so strong, the natural El Niño or human-driven climate change? The answer, published Thursday by World Weather Attribution and Climate Central, is both, but warming won. According to the Associated Press, global warming added about six miles per hour to the storm's already monstrous winds, while El Niño added about five.

What Polo actually did

Polo became a tropical depression on the twentieth of September and blew up into a hurricane within a day. By the twenty-second, the National Hurricane Center had called it a Category Five, one of the fastest-strengthening storms ever seen in the Eastern Pacific, as laid out in the World Weather Attribution report. The storm then stalled and bounced between Category Four and Category Five strength for days.

The AP reports that Polo set a Pacific record by spending two and a half days at Category Five, making it the longest-lasting storm of that strength ever recorded in the basin. Then it weakened. Polo hit a sparsely populated stretch of Baja California Sur as a Category Two, then reached the mainland near Guaymas as a Category One.

The numbers behind the headline

Here is where the science gets spicy. The researchers looked at the hot water that fuels storms and a metric called potential intensity, which estimates how strong a hurricane can get from sea and air conditions. According to the study, climate change made those conditions about twenty-three times more likely, turning a one-in-one-hundred-fifteen-year event into something far more ordinary.

El Niño made the same conditions about fourteen times more likely, which is huge, just not as huge. The waters Polo crossed were roughly thirty-one degrees Celsius, as much as two degrees warmer than normal, according to Euronews, which carried the AP report. Without either factor, the team found, Polo would still have been a monster. Every extra bit of wind speed, though, can dramatically raise damage.

Why warming is the bigger deal

Friederike Otto, who coordinates the World Weather Attribution team, put it bluntly. "El Niño comes and goes, but climate change only gets worse," she said, adding that every hurricane forming in the East Pacific now carries at least this climate signal. Kristina Dahl of Climate Central said El Niño is shifting hazards around the globe, but climate change remains the dominant signal.

Co-author Daniel Gilford offered a traffic analogy. In the Pacific, El Niño flips wind shear into a green light, since it weakens the high-altitude winds that normally decapitate storms. Warm water then acts like a driver flooring the accelerator, and climate change keeps pressing that pedal even in years without El Niño.

Not everyone thinks the study goes far enough

This is a rapid analysis, and it has not been peer reviewed yet. The AP notes that three outside scientists, Jeff Masters of Yale Climate Connections, Michael Mann of the University of Pennsylvania and Carl Schreck of North Carolina State University, believe the study underestimates how much warming added to Polo. Masters pointed to an earlier Gilford paper that found climate change added far more wind speed to Atlantic hurricanes in recent years.

Gilford acknowledged the new number could be a little low but said the team was being conservative. Two separate groups used different methods and landed on the same general conclusion, which, according to the AP, makes the researchers more confident in the result. Brian Tang of the University at Albany, who was not part of the work, said he was initially surprised climate change came out ahead given how extreme this El Niño is.

Luck, rain and what comes next

Polo was not harmless. The World Weather Attribution report describes flooding, fallen trees, landslides that blocked federal highway segments, and deaths from floods in Jalisco and Sonora. Heavy rain from its remnants also reached the American Southwest, where about a thousand people were evacuated in New Mexico over fears of a dam failure. Rainfall trends in observations were striking, though the team said climate models could not reliably quantify the warming link for the rain itself.

The Hurricane Polo study stresses that luck played a role. Early warnings, shelters and coordination across three levels of government helped, but the storm weakened before landfall and mostly missed crowded areas. They point to Hurricane Otis, which hit Acapulco in 2023 and caused an estimated sixteen billion dollars in damage, as proof that where a storm lands matters as much as how strong it is.

For Gen Z, the takeaway is simple and a little unsettling. This super El Niño is expected to peak around December, and warmer oceans are not going back in the box. Read more of our coverage on the climate emergency, and check the full findings from World Weather Attribution and the Euronews report on the AP story.

Even a storm that mostly missed people can teach us how much extra juice a warming planet adds to the next one, and the next one may not miss.