What was done
Noting that earth's polar regions "are expected to provide early signals of a climate change primarily because of the 'ice-albedo feedback' which is associated with changes in absorption of solar energy due to changes in the area covered by the highly reflective sea ice," the authors set about to provide updated and improved estimates of trends in Arctic and Antarctic sea ice cover for the period extending from November 1978 to December 2006, based on data obtained from the Advanced Microwave Scanning Radiometer (AMSR-E), the Special Scanning Microwave Imager (SSM/I) and the Scanning Multichannel Microwave Radiometer (SMMR), where the data from the last two instruments were adjusted to be consistent with the AMSR-E data.

What was learned
Comiso and Nishio report that trends in sea ice extent and area in the Arctic over the period of their analysis were -3.4 ± 0.2 and -4.0 ± 0.2% per decade, respectively, while the corresponding trends in the Antarctic were +0.9 ± 0.2 and +1.7 ± 0.3% per decade.

What it means
If it indeed is true that earth's polar regions should "provide early signals of a climate change," it would appear that the Northern and Southern Hemispheres are scheduled to go their own separate ways in response to a continuation of whatever caused them to behave as they did over the past three decades, which climate alarmists claim were increasing greenhouse gas concentrations. But since we don't really know if either of these two assumptions is true, it is anyone's guess as to what really may lie in store for the planet, as the future gradually unfolds in the years and decades ahead.