Among the many atmosphere-ocean oscillations that occur in the Earth’s global climate system, the Pacific Decadal Oscillation is one of the longest, with swings that may last 30 years or so between phases. Like the El Niño-Southern Oscillation (ENSO) which swings back and forth between El Niño and La Niña, it can regulate global temperatures because of changes in ocean temperatures that affect the air above those regions. You can learn more about the PDO in this 2015 article at Weather Underground at https://www.wunderground.com/blog/JeffMasters/are-we-entering-a-new-period-of-rapid-global-warming.html.

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