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Antarctic Sea Ice (1979-2002)
Reference
Liu, J., Curry, J.A. and Martinson, D.G.  2004.  Interpretation of recent Antarctic sea ice variability.  Geophysical Research Letters 31: 10.1029/2003GL018732.

What was done
The authors used sea ice concentration data retrieved from the scanning multichannel microwave radiometer on the Nimbus 7 satellite and the spatial sensor microwave/imager on several defense meteorological satellites to develop a quality-controlled history of Antarctic sea ice variability covering an entire 22-year solar cycle (1979-2002) that includes different states of the Antarctic Oscillation and several ENSO events, after which they evaluated total sea ice extent and area trends by means of linear least-squares regression.

What was learned
Liu et al. report that "overall, the total Antarctic sea ice extent (the cumulative area of grid boxes covering at least 15% ice concentrations) has shown an increasing trend (~4,801 km2/yr)."  In addition, they find that "the total Antarctic sea ice area (the cumulative area of the ocean actually covered by at least 15% ice concentrations) has increased significantly by ~13,295 km2/yr, exceeding the 95% confidence level," noting that "the upward trends in the total ice extent and area are robust for different cutoffs of 15, 20, and 30% ice concentrations (used to define the ice extent and area)."

What it means
As the great bulk of Antarctica continues to cool [see Temperature (Trends - Regional: Antarctica) in our Subject Index], so too does the amount of sea ice that surrounds the continent continue to increase, both of which observations provide little justification (actually, none at all) for the climate-alarmist claim that CO2-induced global warming is a reality, especially when most climate models predict it should be most evident in earth's polar regions, where it obviously is nowhere to be seen [see also Temperature (Trends - Regional: Arctic) in our Subject Index].


Reviewed 16 June 2004