While El Niño is being blamed for an outbreak of floods, storms and unseasonable temperatures across the planet, a much slower-moving cycle of the Pacific Ocean has also been playing a role in record-breaking warmth. The recent effects of both ocean cycles are being amplified by climate change.
A 2014 flip was detected in the sluggish and elusive ocean cycle known as the Pacific Decadal Oscillation, or PDO, which also goes by other names, including the Interdecadal Pacific Oscillation. Despite uncertainty about the fundamental nature of the PDO, leading scientists link its 2014 phase change to a rapid rise in global surface temperatures.
The effects of the PDO on global warming can be likened to a staircase, with warming leveling off for periods, typically of more than a decade, and then bursting upward.