Contrary to what one would expect on the basis of these predictions, and especially in light of what climate alarmists call the unprecedented warming of the past quarter-century, the two scientists observed statistically significant increases in both sea ice area and sea ice extent over the period studied; and when they combined their results with results for the preceding period of 1978-1987, both parameters continued to show increases over the sum of the two periods (1978-1996).  In addition, they determined that the 1990s also experienced increases in the length of the sea ice season.

Watkins and Simmonds' findings, i.e., that Southern Ocean sea ice has increased in area, extent and season length since at least 1978, are also supported by a number of other studies.  Hanna (2001), for example, published an updated analysis of Antarctic sea ice cover based on Special Sensor Microwave Imager data for the period October 1987-September 1999, finding that the serial sea ice data depict "an ongoing slight but significant hemispheric increase of 3.7(±0.3)% in extent and 6.6(±1.5)% in area."  Likewise, Parkinson (2002) utilized satellite passive-microwave data to calculate and map the length of the sea-ice season throughout the Southern Ocean for each year of the period 1979-1999, finding that although there are opposing regional trends, a "much larger area of the Southern Ocean experienced an overall lengthening of the sea-ice season … than experienced a shortening."

Zwally et al. (2002) also utilized passive-microwave satellite data to study Antarctic sea ice trends.  Over the 20-year period 1979-1998, they report that the sea ice extent of the entire Southern Ocean increased by 11,181 ± 4,190 square km per year, or by 0.98 ± 0.37 percent per decade, while sea ice area increased by nearly the same amount: 10,860 ± 3,720 square km per year, or by 1.26 ± 0.43 percent per decade.  And in contradiction of the climate-alarmist claim that earth's climate should exhibit greater extremes when warming (which climate alarmists claim is occurring), they observed that the variability of monthly sea ice extent declined from 4.0% over the first ten years of the record, to 2.7% over the last ten years (which have supposedly been the warmest of the past millennium, according to the world's climate alarmists).

In yet another assessment of Antarctic sea ice behavior, Yuan and Martinson (2000) analyzed Special Sensor Microwave Imager data together with data derived from brightness temperatures measured by the Nimbus-7 Scanning Multichannel Microwave Radiometer.  Among other things, they determined that the mean trend in the latitudinal location of the Antarctic sea ice edge over the prior 18 years was an equatorward expansion of 0.011 degree of latitude per year.  But that is still not the end of the scientific testimony in this case.

Vyas et al. (2003) analyzed data from the multi-channel scanning microwave radiometer carried aboard India's OCEANSAT-1 satellite for the period June 1999-May 2001, which they combined with data for the period 1978-1987 that were derived from space-based passive microwave radiometers carried aboard earlier Nimbus-5, Nimbus-7 and DMSP satellites to study secular trends in sea ice extent about Antarctica over the period 1978-2001.  Their work revealed that the mean rate of change of sea ice extent for the entire Antarctic region over this period was an increase of 0.043 M km² per year.  In fact, they concluded that "the increasing trend in the sea ice extent over the Antarctic region may be slowly accelerating in time, particularly over the last decade," noting that the "continually increasing sea ice extent over the Antarctic Southern Polar Ocean, along with the observed decreasing trends in Antarctic ice surface temperature (Comiso, 2000) over the last two decades, is paradoxical in the global warming scenario resulting from increasing greenhouse gases in the atmosphere."

In a somewhat similar study, Cavalieri et al. (2003) extended prior satellite-derived Antarctic sea ice records several years by bridging the gap between Nimbus 7 and earlier Nimbus 5 satellite data sets with National Ice Center digital sea ice data, finding that sea ice extent about the continent increased at a mean rate of 0.10 ± 0.05 x 10⁶ km² per decade between 1977 and 2002.  Likewise, Liu et al. (2004) 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 the period 1979-2002, which 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.  They found 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 determined 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)."

Finally, on a somewhat different note, Elderfield and Rickaby (2000) concluded that the sea ice cover of the Southern Ocean during glacial periods may have been as much as double the coverage of modern winter ice, suggesting that "by restricting communication between the ocean and atmosphere, sea ice expansion also provides a mechanism for reduced CO2 release by the Southern Ocean and lower glacial atmospheric CO2."

In considering the findings of the several research papers described above that apply to the last few decades, if one were to infer anything about the planet in terms of what state-of-the-art climate models predict and what is known about real-world sea ice behavior around Antarctica, one would be tempted to conclude that the globe is currently in a cooling mode.  Does that mean that the IPCC-endorsed air temperature history of the planet is in error?  Or does it mean that the climate models are in error?  Or does it mean that both are in error?  All three of these important questions need to be pondered before rushing headlong into adopting expensive and economy-wrenching measures to battle what could well turn out to be an imaginary enemy, i.e., CO2-induced global warming.

References
Cavalieri, D.J., Parkinson, C.L. and Vinnikov, K.Y.  2003.  30-Year satellite record reveals contrasting Arctic and Antarctic decadal sea ice variability.  Geophysical Research Letters 30: 10.1029/2003GL018031.

Comiso, J.C.  2000.  Variability and trends in Antarctic surface temperatures from in situ and satellite infrared measurements.  Journal of Climate 13: 1674-1696.

Elderfield, H. and Rickaby, R.E.M.  2000.  Oceanic Cd/P ratio and nutrient utilization in the glacial Southern Ocean.  Nature 405: 305-310.

Hanna, E.  2001.  Anomalous peak in Antarctic sea-ice area, winter 1998, coincident with ENSO.  Geophysical Research Letters 28: 1595-1598.

Parkinson, C.L.  2002.  Trends in the length of the Southern Ocean sea-ice season, 1979-99.  Annals of Glaciology 34: 435-440.

Vyas, N.K., Dash, M.K., Bhandari, S.M., Khare, N., Mitra, A. and Pandey, P.C.  2003.  On the secular trends in sea ice extent over the antarctic region based on OCEANSAT-1 MSMR observations.  International Journal of Remote Sensing 24: 2277-2287.

Watkins, A.B. and Simmonds, I.  2000.  Current trends in Antarctic sea ice: The 1990s impact on a short climatology.  Journal of Climate 13: 4441-4451.

Yuan, X. and Martinson, D.G.  2000.  Antarctic sea ice extent variability and its global connectivity.  Journal of Climate 13: 1697-1717.

Zwally, H.J., Comiso, J.C., Parkinson, C.L. Cavalieri, D.J. and Gloersen, P.  2002.  Variability of Antarctic sea ice 1979-1998.  Journal of Geophysical Research 107: 10.1029/2000JC000733.