The recent, mysterious expansion of Antarctic ice could be overestimated because of a data-analysis error, according to US scientists.

Ian Eisenman at the Scripps Institution of Oceanography in La Jolla, California, and his colleagues found the mistake when they compared two versions of satellite data on Southern Hemisphere sea ice that were calibrated differently. The incorrect calibration of one of the data sets might account for more than half of the jump in Antarctic sea-ice growth.

The finding means that either the 2007 or the 2013 report by the Intergovernmental Panel on Climate Change reflects this error, but the authors were not able to determine which one.

Cryosphere 8, 1289–1296 (2014) Footnote 1