Heat is the fuel of hurricanes, and the North Pacific last summer was the hottest on record, a University of Hawaii climate scientist has calculated.
"This summer has seen the highest global mean sea surface temperatures ever recorded since their systematic measuring started," said Axel Timmermann, a UH oceanography professor, in a statement Thursday. "Temperatures even exceed those of the record-breaking 1998 El Nino year."
Sea surface temperatures have remained fairly stable since 2000, a phenomenon known as the global warming hiatus.
The recent temperature spikes mean that hiatus "has come to an end," said Timmermann, affiliated with the International Pacific Research Center. "The ocean warming has picked up speed again."
Both the global and North Pacific sea surface temperatures were record-breaking, even without an El Nino, he said.
"The main contributor to this recent warming is the North Pacific, which has warmed up far beyond any recorded value, shifting hurricane tracks, weakening trade winds and causing coral bleaching in the Hawaiian Islands," Timmermann said in a report. "An initial extratropical sea surface temperature anomaly already developed in January 2014. A few months later, in April and May 2014, a massive wind-triggered equatorial sloshing of warm water from the western to the eastern tropical Pacific and the subsequent spreading of this water along the North American coast, released large amounts of energy to the surface that had been locked up in the western tropical Pacific for almost a decade. Additional warming contributions came from record-breaking greenhouse gas concentrations and an unusual weakening of the North Pacific summer trade winds, which reduced the evaporative cooling of the oceans."
In July, ocean surfaces were nearly 1 degree Fahrenheit (0.55 Celsius) above the average since 1890, topping the previous record of 0.9 F in 1998, Timmermann said. In the North Pacific the temperatures were 1.44 degrees Fahrenheit above average, or 0.45 degree warmer than the 1998 peak.
"It’s a remarkable situation, and I’ve never seen warming of the North Pacific like that," Timmermann told New Scientist magazine.
