Keywords: Southern Hemisphere Sea Ice Extent Anomalies.png Southern Hemisphere Antarctic Sea Ice Extent Anomalies Ice extent anomalies are plotted as a time series of percent differences between the total extent for the month in question and the mean for that month where the mean is based on the January 1979 - December 2000 portion of the data set The trend in percent change per decade is obtained using least squares regression and a 95 confidence interval for the resulting slope is given http //nsidc org/data/seaice_index/s_plot html 2008-09 National Snow and Ice Data Center 300px left graph PD-USGov Trend analysis Ecological trends Antarctic sea ice |