Ka-Kit Tung of the University of Washington and Chen Xianyao of the Ocean University of China have published research in Science (August 2014) that may explain the pause in global warming.Dr. Tung, pictured below, is Professor of Applied Mathematics and Adjunct Professor in Atmospheric Science at the University of Washington.
|Ka-Kit Tung, Ph.D.|
Global temperatures rose from the 1970s to the late 1990s, but have been relatively stable since. "Over the past few years, one of the biggest questions in climate science has been why, since the turn of the century, average surface-air temperatures on Earth have not risen, even thought the concentration in the atmosphere of heat-trapping carbon dioxide has continued to go up." The Economist, August 23, 2014.
The answer, suggested in the research by Tung and Chen, is that global warming seems to have paused while the deep ocean takes the heat instead. The thermal capacity of the oceans far exceeds that of the atmosphere, so the oceans can store up to ninety percent of the heat buildup caused by increased concentrations of greenhouse gases such as carbon dioxide.Chen and Tung used observational data to trace the pathways of recent ocean heating. They conclude that the deep Atlantic and Southern Oceans, but not the Pacific, have absorbed the excess heat that would otherwise have fueled continued warming. They also note trends of several decades in which the oceans absorb and release heat.The study suggests that a natural cycle of ocean currents has caused the phenomenon by drawing heat from shallow waters down almost a mile into the depths of the Atlantic and Southern Oceans. If the authors are correct, we can expect to see surface-air temperatures continue to be mitigated for another decade. Dr. Tung of the University of Washington said: "Historically the cool period lasted 20 to 35 years. The current period already lasted 15 years, so roughly there [are] 10 more years to go."