The globally averaged sea surface temperature in 2013 was among the 10 highest on record, with the North Pacific reaching an historic high temperature. ENSO-neutral conditions and a negative Pacific Decadal Oscillation pattern had the largest impacts on global sea surface temperature in 2013.
Upper ocean heat content has increased significantly over the past two decades. An estimated 70 percent of the excess heat has accumulated in the top 2,000 feet of the ocean, and the rest has flowed into deeper ocean layers.
Sea surface temperature—the average temperature of water at the surface of the global ocean—is a key indicator of the ocean's status.
The ocean’s ability to store and release heat over long periods of time gives it a central role in stabilizing Earth’s climate system. But when the ocean absorbs more heat than it releases, its heat content increases. Warming causes water to expand, raising global sea level. Higher water temperatures can also threaten marine ecosystems, disrupting fisheries and the people who depend upon them. The upper ocean held more heat than average in 2012 in most of the major ocean basins, with the exception of the Pacific Ocean.
Understanding the Pacific Decadal Oscillation (PDO) as multiple layers of ice cream. And how is it related to the El Niño-Southern Oscillation?