Global warming 'hiatus' means heat is hiding in ocean

An apparent slowdown in the Earth's surface warming in the last 15 years could be due to that heat being trapped in the deep Atlantic and Southern Ocean, researchers said Thursday. The findings in the journal Science suggest that such cycles tend to last 20-35 years, and that global warming will likely pick up again once that heat returns to surface waters.
"Every week there's a new explanation of the hiatus," said co-author Ka-Kit Tung, a University of Washington professor of applied mathematics and adjunct faculty member in atmospheric sciences. "We looked at observations in the ocean to try to find the underlying cause." Tung and Xianyao Chen of the Ocean University of China studied deep-sea temperatures from floats that sample the water as deep as 6,500 feet (2,000 meters) depth. They found that more heat began to sink around 1999, just when the rapid warming of the 20th century began to flatline. The movement of more heat into the water explains how surface temperatures could stay close to the same, even as mounting greenhouse gases trap more solar heat at the Earth's surface, researchers said.