See highlights from the 2017 issue of the planet's most comprehensive annual physical, the American Meteorological Society's State of the Climate report.
ocean heat content
In 2014, the upper ocean held more heat than average throughout most of the major ocean basins.
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.
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.
Except for some La Niña-cooled regions of the tropical Pacific and a few other cool spots, the upper ocean held more heat than average in 2011 in the Pacific, Atlantic, Indian, and Southern Oceans.
More than 90 percent of the warming that has happened on Earth over the past 50 years has occurred in the ocean. Not all of that heating is detectable yet at the surface