Study Says Global Warming Did More Than El Niño to Power Up Hurricane Polo

A new study says that both climate change and a weather pattern called El Niño helped make Hurricane Polo one of the most powerful storms ever seen in the Pacific Ocean. The storm rapidly grew from a tropical storm into a Category 5 hurricane — the strongest level — in just 24 hours. Scientists say climate change, caused by burning coal, oil, and gas, was the bigger reason the storm got so strong. The study was published by two science teams called World Weather Attribution and Climate Central.

Researchers found that global warming added about 6 miles per hour to Polo's already powerful winds. El Niño — a natural, temporary warming of parts of the Pacific Ocean — added about 5 miles per hour. Together, these two forces made the conditions that fueled the hurricane far more dangerous than they would have been otherwise. Climate change made those dangerous conditions 23 times more likely, while El Niño made them 14 times more likely.

The warm ocean water was a key ingredient in Polo's power. The water measured 88 degrees Fahrenheit, which was up to 3.6 degrees warmer than normal. Warm water acts like fuel for hurricanes, helping them grow bigger and stronger. Both climate change and El Niño played a role in heating up those waters.

Hurricane Polo set a record for how long it stayed at Category 5 strength in the Pacific — two and a half days. Even though Polo weakened before it hit a lightly populated area of Mexico, scientists were still amazed by how fast it grew. That kind of rapid growth, called rapid intensification, is something researchers are working hard to understand. This year's especially strong El Niño has helped create record-breaking storms in terms of both strength and how long they last.

Climate scientist Friederike Otto, one of the study's co-authors, explained why climate change is such a serious concern. She said El Niño is temporary, but climate change keeps getting worse over time. "El Niño comes and goes, but climate change only gets worse," she said. As long as people keep burning fossil fuels, she warned, future storms in the Pacific will only grow stronger.

The researchers used a method that compared what really happened to what might have happened in a world that had not warmed up. Two separate science teams used slightly different methods but reached the same general conclusion, which made them more confident in the results. However, the study has not yet gone through peer review, which is when other scientists carefully check the work. Peer review is considered the gold standard in science.

One scientist compared El Niño and climate change to a car on a road. In the Pacific Ocean, El Niño acts like a green light, letting storms grow freely. Then the warm water — heated by both El Niño and climate change — acts like a driver pressing hard on the gas pedal. This combination can cause a storm to grow extremely fast and become very dangerous.

Some scientists not involved in the study think it may actually underestimate how much climate change helped Polo. Jeff Masters, Michael Mann, and Carl Schreck all believe climate change's impact could be even larger than reported. They pointed to another study that found climate change added 16 miles per hour to Atlantic hurricanes between 2019 and 2023. Study co-author Daniel Gilford said he was being careful in his estimates, but admitted the report might be slightly underestimating climate change's role.