May 21, 2010
From Science News: "Earth’s upper ocean warmed substantially between 1993 and 2008, a new analysis reveals. The trend signals growing heat storage in oceans, researchers say, a result of human-caused warming. The new study, reported in the May 20 Nature, combined oceanographic data gathered worldwide between 1993 and 2008, the time period with the most data available. During that period, the upper 700 meters of the world’s ocean warmed on average by about 0.18 degrees Celsius, says John M. Lyman, a physical oceanographer with the National Oceanographic and Atmospheric Administration in Seattle. “But that little bit of temperature increase represents a lot of heat,” Lyman says. In fact, Lyman and his colleagues estimate that the total heat added to the oceans during that 15-year period is equivalent to the energy that would be released by exploding about 2 billion Hiroshima-scale atomic bombs, he says. Most of that added heat comes from the greenhouse effect, which in turn stems from the heat-trapping effect of gases like carbon dioxide, Lyman says. Because water has a vastly higher capacity to absorb heat than air, between 80 and 90 percent of the heat trapped by the greenhouse effect eventually ends up in the ocean. "