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ClimatEnerGeopolitics
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As El Nino Emerges, Ominous Findings on Ocean HeatThe long-term heat gain in the top 700 meters (.43 miles) of the world’s oceans has likely been underestimated by as much as half, according to Lawrence Livermore National Laboratories research scientist Paul Durack. Earlier measurements had lowballed heat accumulation due to historically sparse observations for large parts of the ocean. The figures were especially low for the Southern Hemisphere, which contains about 60 percent of the planet’s oceans but was very poorly sampled — until Argo, an array of around 3,500 floating sensors, was deployed worldwide in 2005. An updated analysis by Durack and colleagues found that from 1970 to 2004, the upper 700 meters of oceans in the Southern Hemisphere had gained from 48 to 166 percent more heat than earlier observations had estimated. Globally, the findings suggest, upper oceans hold 24 to 58 percent more heat than most current climate models assumed. “We have likely been missing a portion of the heat,” said Durack. His study and other recent research, he said, suggests that “we may need to go back and start recalculating the climate sensitivity estimates of the earth.” Excess energy is also penetrating deeper into the ocean and farther south, Roemmich and colleagues found, analyzing Argo data measuring heat down to 2,000 meters (1.24 miles). The network provides the first comprehensive measurements of the deeper ocean; most prior readings stopped at 700 meters. The researchers found that from two-thirds to 98 percent of the substantial ocean heat gain between 2006 and 2013 took place well south of the equator, where giant gyres drew it down. And half of the gain occurred from 500 to 2,000 meters deep. Roemmich estimates that at depths from 500 to 2000 meters, oceans are warming by .002 degrees Celsius every year, and in the top 500 meters, they’re gaining .005 degrees C. annually. While that may not seem like a big temperature jump, it amounts to a staggering load of heat when multiplied throughout the depths of this immense system that covers 70 percent of the planet. http://climatecrocks.com/2015/03/31/as-el-nino-emerges-ominous-findings-on-ocean-heat/ |
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