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By Steve Hall |
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September 26, 2010
- Scientists analyzing measurements taken in the deep ocean
around the globe over the past two decades find a warming trend that
contributes to sea level rise, especially around
Greenhouse gases
in the atmosphere, such as carbon dioxide, cause heating of the Earth.
Over the past few decades, at least 80 percent of this heat energy has
gone into the ocean, warming it in the process. ?Previous studies have shown that the upper ocean is warming, but our analysis determines how much additional heat the deep ocean is storing from warming observed all the way to the ocean floor,? said Sarah Purkey, an oceanographer at the University of Washington and lead author of the study. |
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This study shows
that the deep ocean ? below about 3,300 feet ? is taking up about 16
percent of what the upper ocean is absorbing. The authors note that
there are several possible causes for this deep warming: a shift in
Southern Ocean winds, a change in the density of what is called
Antarctic Bottom Water, or how quickly that bottom water is formed near
the Antarctic, where it sinks to fill the deepest, coldest portions of
the ocean around much of the globe.
The scientists
found the strongest deep warming around
?A warming Earth
causes sea level rise in two ways,? said Gregory Johnson, a NOAA
oceanographer at the Pacific Marine Environmental Laboratory in |