The top layer of water may protrude 150 or more centimeters above sea level. This isn't so hard to picture if you think about tides, which also pile water up above sea level. It contains more energy than has been procured from all the fossil fuels burned in the United States since the beginning of the century - that's all the gasoline in all the cars, the coal in all the power plants, the natural gas in all the furnaces. It would take more than a million large power plants, at 1,000 megawatts each, running full tilt for a year, to heat the ocean that much. Or if you want to think in more violent terms, that's all the energy produced by about half a million 20 megaton hydrogen bombs, gone into heating water.
Scientists are divided on what triggers the buildup.
There the waters pile up like driftwood blown into a harbor. The birth of El Nino. As spring became summer in 1997, a Kelvin Wave of warm water crossed the Pacific and accumulated off the coast of South America, shown here in red. See the 775K animation of the wave. This vacuum sucks the trade winds toward it, making them stronger.