>2015’s sharp spike in temperatures was aided by a strong El Nino weather pattern late in the year that caused ocean waters in the central Pacific to heat up. B

>2015’s sharp spike in temperatures was aided by a strong El Nino weather pattern late in the year that caused ocean waters in the central Pacific to heat up. But the unusual warming started early and steadily gained strength in a year in which ten of 12 months set all-time records, scientists said.