Davy Jones’s heat locker

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 though the concentration in the atmosphere of heat-trapping carbon dioxide has continued to go up. This “pause” in global warming has been seized on by those sceptical that humanity needs to act to curb greenhouse-gas emissions or even (in the case of some extreme sceptics) who think that man-made global warming itself is a fantasy. People with a grasp of the law of conservation of energy are, however, sceptical in their turn of these positions and doubt that the pause is such good news. They would rather understand where the missing heat has gone, and why—and thus whether the pause can be expected to continue.

The most likely explanation is that it is hiding in the oceans, which store nine times as much of the sun’s heat as do the atmosphere and land combined. But until this week, descriptions of how the sea might do this have largely come from computer models. Now, thanks to a study published in Science by Chen Xianyao of the Ocean University of China, Qingdao, and Ka-Kit Tung of the University of Washington, Seattle, there are data.