WASHINGTON, OCT 15: Climate change contributed more than the natural El Niño phenomenon to the rapid intensification of Hurricane Polo, which became the longest-lasting Category 5 storm ever recorded in the Pacific, according to a new study released on Thursday.
The joint research by World Weather Attribution and Climate Central found that global warming caused by the burning of fossil fuels, including coal, oil and gas, added nearly 10 kilometres per hour to the hurricane’s wind speed. El Niño contributed an additional increase of approximately 8 kilometres per hour.
Hurricane Polo intensified dramatically last month, remaining at Category 5 strength for around two-and-a-half days. The storm rapidly strengthened from a tropical storm to a Category 5 hurricane in approximately 24 hours, attracting significant attention from climate scientists.
Researchers found that climate change made the conditions that fuelled the hurricane about 23 times more likely, while El Niño increased the likelihood of those conditions by approximately 14 times.
The study linked the storm’s intensification to exceptionally warm ocean waters, which reached around 31.2 degrees Celsius—up to 2 degrees above normal in some areas.
Climate Change Intensifies Hurricane Risks
Friederike Otto, a climate scientist and co-author of the study who coordinates the World Weather Attribution research team, said both climate change and El Niño contributed to the hurricane’s strength, but global warming had the greater influence.
She warned that while El Niño is a temporary natural phenomenon, climate change is a long-term problem that will continue to intensify as long as fossil fuel emissions remain high.
According to researchers, Hurricane Polo would still have been a powerful storm even without the effects of climate change and El Niño. However, additional wind speed can significantly increase a hurricane’s destructive potential.
The storm eventually weakened considerably before making landfall in a sparsely populated area of Mexico, limiting its potential impact on densely populated communities.
Why Did Hurricane Polo Strengthen So Quickly?
Scientists examined how unusually warm ocean temperatures and atmospheric conditions contributed to the hurricane’s rapid development.
Warm ocean water supplies the energy that fuels tropical cyclones. When sea surface temperatures rise, storms can draw additional heat and moisture from the ocean, potentially accelerating their intensification.
El Niño also influences wind patterns in the atmosphere. In the eastern Pacific, it can reduce the upper-level winds that otherwise weaken developing storms, creating more favourable conditions for hurricanes to strengthen.
Researchers compared the conditions surrounding Hurricane Polo in today’s warmer climate with a hypothetical world that had not experienced approximately 1.4 degrees Celsius of global warming since pre-industrial times.
Although the two research teams used different methods and measurements, both reached broadly similar conclusions.
However, the findings have not yet undergone peer review, meaning the results should be considered preliminary.
Scientists Highlight the Long-Term Threat
Kristina Dahl, vice president of science at Climate Central, said the findings highlighted the continuing influence of climate change, even as El Niño shifts weather patterns and affects rainfall and drought risks around the world.
Other scientists who were not involved in the research said they were surprised that climate change emerged as a stronger influence than El Niño, given the intensity of the current El Niño event.
Some experts also suggested that the study might underestimate the contribution of global warming to Hurricane Polo’s strength.
Daniel Gilford, a Climate Central scientist and co-author of the study, acknowledged that the estimates could be conservative but said the researchers had considered additional atmospheric factors in their analysis.
The findings add to growing scientific concerns about the influence of rising global temperatures on extreme weather events. Researchers warn that continued fossil fuel emissions could further increase the likelihood of conditions favourable to powerful tropical cyclones.
The study underscores the importance of understanding how natural climate patterns and human-caused global warming interact to influence the intensity of future hurricanes.
