A new study finds that climate change and El Nio combined to rev up last month's explosively intensifying Hurricane Polo, which was the longest-lasting Category 5 storm ever to churn in the Pacific.

Global warming caused by the burning of coal, oil and gas was the bigger of the two culprits, adding about 6 mph (nearly 10 kph) to its already monstrous strength, according to a joint study published Thursday by the science teams World Weather Attribution and Climate Central.

El Nio contributed a bit less, about 5 mph (8 kph), a study co-author said.