The Guardian editorializes:
There is, however, a serious debate about why the observed temperatures have not kept pace with computer-modelled predictions and where the heat that should have registered on the global thermometer has hidden itself. One guess – supported by some sustained but still incomplete research – is that the deep oceans are warming: that is, the extra heat that should be measurable in the atmosphere has been absorbed by the sea. This is hardly good news: atmosphere and ocean play on each other, and any stored heat is likely to be returned to the atmosphere sooner or later, in unpredictable ways. The real lesson from the latest finding is that there is a lot yet to be understood about how the planet works, and precisely how ocean and atmosphere distribute warmth from the equator to the poles.