Study Finds Earth's Ocean Abyss Has Not Warmed   
       
   Oct. 6, 2014: The cold waters of Earth's deep ocean have not warmed measurably   
   since 2005, according to a new NASA study, leaving unsolved the mystery of why   
   global warming appears to have slowed in recent years.   
       
   Scientists at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California,   
   analyzed satellite and direct ocean temperature data from 2005 to 2013 and   
   found the ocean abyss below 1.24 miles (1,995 meters) has not warmed   
   measurably. Study coauthor Josh Willis of JPL said these findings do not throw   
   suspicion on climate change itself.   
       
   "The sea level is still rising," Willis noted. "We're just trying to   
   understand the nitty-gritty details."   
       
   http://www.nasa.gov/sites/default/files/anemone-full.jpg   
       
   Deep sea creatures, like these anemones at a hydrothermal vent, are not yet   
   feeling the heat from global climate change. Although the top half of the   
   ocean continues to warm, the bottom half has not increased measurably in   
   temperature in the last decade. Image credit: NERC   
       
   In the 21st century, greenhouse gases have continued to accumulate in the   
   atmosphere, just as they did in the 20th century, but global average surface   
   air temperatures have stopped rising in tandem with the gases. The temperature   
   of the top half of the world's oceans -- above the 1.24-mile mark -- is still   
   climbing, but not fast enough to account for the stalled air temperatures.   
       
   Many processes on land, air and sea have been invoked to explain what is   
   happening to the "missing" heat. One of the most prominent ideas is that the   
   bottom half of the ocean is taking up the slack, but supporting evidence is   
   slim. This latest study is the first to test the idea using satellite   
   observations, as well as direct temperature measurements of the upper ocean.   
   Scientists have been taking the temperature of the top half of the ocean   
   directly since 2005, using a network of 3,000 floating temperature probes   
   called the Argo array.   
       
   "The deep parts of the ocean are harder to measure," said JPL's William   
   Llovel, lead author of the study published Sunday in the journal Nature   
   Climate Change. "The combination of satellite and direct temperature data   
   gives us a glimpse of how much sea level rise is due to deep warming. The   
   answer is -- not much."   
       
   The study took advantage of the fact that water expands as it gets warmer. The   
   sea level is rising because of this expansion and the water added by glacier   
   and ice sheet melt.   
       
   http://www.nasa.gov/multimedia/imagegallery/image_feature_2515.html   
       
   While the upper part of the world's oceans continue to absorb heat from global   
   warming, ocean depths have not warmed measurably in the last decade. This   
   image shows heat radiating from the Pacific Ocean as imaged by the NASA's   
   Clouds and the Earth's Radiant Energy System instrument on the Terra   
   satellite. (Blue regions indicate thick cloud cover.) Image credit: NASA To   
   arrive at their conclusion, the JPL scientists did a straightforward   
   subtraction calculation, using data for 2005-2013 from the Argo buoys, NASA's   
   Jason-1 and Jason-2 satellites, and the agency's Gravity Recovery and Climate   
   Experiment (GRACE) satellites. From the total amount of sea level rise, they   
   subtracted the amount of rise from the expansion in the upper ocean, and the   
   amount of rise that came from added meltwater. The remainder represented the   
   amount of sea level rise caused by warming in the deep ocean.   
       
   The remainder was essentially zero. Deep ocean warming contributed virtually   
   nothing to sea level rise during this period.   
       
   Coauthor Felix Landerer of JPL noted that during the same period warming in   
   the top half of the ocean continued unabated, an unequivocal sign that our   
   planet is heating up. Some recent studies reporting deep-ocean warming were,   
   in fact, referring to the warming in the upper half of the ocean but below the   
   topmost layer, which ends about 0.4 mile (700 meters) down.   
       
   Landerer also is a coauthor of another paper in the same journal issue on   
   1970-2005 ocean warming in the Southern Hemisphere. Before Argo floats were   
   deployed, temperature measurements in the Southern Ocean were spotty, at best.   
   Using satellite measurements and climate simulations of sea level changes   
   around the world, the new study found the global ocean absorbed far more heat   
   in those 35 years than previously thought -- a whopping 24 to 58 percent more   
   than early estimates.   
       
   Both papers result from the work of the newly formed NASA Sea Level Change   
   Team, an interdisciplinary group tasked with using NASA satellite data to   
   improve the accuracy and scale of current and future estimates of sea level   
   change. The Southern Hemisphere paper was led by three scientists at Lawrence   
   Livermore National Laboratory in Livermore, California.   
       
   Credits:   
   Production editor: Dr. Tony Phillips | Credit: Science@NASA   
       
   More information:   
       
   NASA monitors Earth's vital signs from land, air and space with a fleet of   
   satellites and ambitious airborne and ground-based observation campaigns. NASA   
   develops new ways to observe and study Earth's interconnected natural systems   
   with long-term data records and computer analysis tools to better see how our   
   planet is changing. The agency shares this unique knowledge with the global   
   community and works with institutions in the United States and around the   
   world that contribute to understanding and protecting our home planet.   
       
   For more information about NASA's Earth science activities in 2014, visit:   
   http://www.nasa.gov/earthrightnow   
       
   For more information on ocean surface topography from space, visit:   
   http://sealevel.jpl.nasa.gov   
       
   More information on NASA's GRACE satellites is available at: htt   
   ://grace.jpl.nasa.gov   
       
   For more information on the Argo array, visit: http://www.argo.u   
   sd.edu/index.html   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.99   
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