Both climate change and a strong El Niño combined to cause Hurricane Polo to explosively intensify from a tropical storm to a Category 5 monster in just 24 hours. But a study finds that global warming is the bigger culprit. Polo was fueled by super-warm water. The burning of coal, oil and gas made that temperature hike 23 times more likely, while El Niño made it 14 times more likely. Climate change added about 6 mph to its already top-of-the-chart wind, and El Niño contributed about another 5 mph. The study was published Thursday by World Weather Attribution and Climate Central.