Antarctic sea ice expanding despite global warming

Science : The observation that Antarctic sea ice appears to be expanding seems to run counter to the fact that Earth’s climate is growing warmer. To find out why, Ian Eisenman of the Scripps Institution of Oceanography in San Diego, California, and colleagues decided to look more closely at the data behind the 2007 and 2013 reports from the Intergovernmental Panel on Climate Change. In comparing them, the researchers found that the data had been recalibrated several times to ensure continuity from one satellite to the next over time and that discrepancies existed between the two different versions of the algorithm used to process the data. While it does indeed appear that Antarctic sea ice is expanding overall, the expansion varies regionally and seasonally, and in some places the ice is actually retreating. It is that complex spatial pattern that researchers seek to understand, and more thorough satellite data calibration methods may be needed to do so.