ARGO is an array of floats drifting freely around the oceans, 2,800-strong so far and still growing. Each float shuttles back and forth between the surface and the ocean depths measuring temperature and salinity, then sending data home via satellite when it is at the surface.

In 2006, data from the array led a team of scientists to the surprising conclusion that the world's oceans had cooled during 2003-05 - exceptionally warm years in terms of global surface temperature. The team published its findings in Geophysical Research Letters1. Such apparent cooling was seized on by people keen to highlight the uncertainties in forecasts of global warming2.

That cooling has now been shown to be an artefact. In some of the buoys - they are manufactured in separate batches - a software glitch caused the temperature and salinity data to be associated with the wrong depths. When the problem data are excluded from the analysis, the cooling trend drops below the level of statistical significance.

From Energy Bulletin among other sources including Nature if you pay.