Apologies for the length of this post.Lovuian wrote:
n parts of Antarctica, the yearly rate of thinning from 2003 to 2007 was 50 per cent higher than it was from 1995 to 2003.
The more the ice melts, the more water surrounds and eats away at the remaining ice.
'To some extent it's a runaway effect. The question is how far will it run?' said Hamish Pritchard of the British Antarctic Survey.
'It's more widespread than we previously thought.'
The following studies put the statement about the “rates of thinning” into perspective. There is considerable variation from year to year. The “rates of thinning” statement is based on selective data, it would seem. The trend is up. The following is summarized from: Taylor, G. Antarctic Temperature and Sea Ice Trends over the Last Century
. From: http://icecap.us/images/uploads/antarct ... _final.pdf
1. Zwally, et al (2002) used “a systematically calibrated and analyzed data set for 20.2 years (1979–1998).” They report that the total Antarctic sea ice extent increased by 11,180 ± 4190 sq. km. per year.
2. Vyas, et al (2003) used data from several satellite platforms (Nimbus-7, DMSP and OCEANSAT-1) to estimate trends in sea ice around Antarctica. They found decreasing sea ice in the Weddell Sea, increases in the Ross Sea, and insignificant changes elsewhere. For the continent as a whole there has been an increase in sea ice, a “weak but consistent increasing trend of approximately 43,000 sq. km. per year.”
3. Liu, et al (2004) report that total Antarctic sea ice (the area covered by at least 15% ice concentration) has increased significantly since 1979, by about 13,295 sq. km. per year.
4. Cavalieri, et al (2004) extended the analysis of Arctic and Antarctic sea ice variability from two to three decades (1973–2002). They found that the Antarctic sea ice extent decreased dramatically over the period 1973–1977, then gradually increased. Over the period 1979-2002, Antarctic sea ice extent increased by 0.11 ± 0.05 million sq. km. per decade.
5. Antarctic Sea Ice Area Anomalies, 1978-2005, from NSIDC (2006) shows the annual variability in the Antarctic area along with the 30 year trend.
Conclusion: The data clearly show that Antarctica as a whole is seeing increases in sea ice extent in recent decades, in spite of what climate models suggest should be occurring: steady warming. There are regional differences, with Weddell Sea ice extent decreasing and Ross Sea ice increasing, but overall the pattern is clear: there is more ice, not less, surrounding Antarctica.
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, VOL. 107, NO. C5, 10.1029/2000JC000733, 2002
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.
Liu, J., Curry, J.A. and Martinson, D.G. 2004. Interpretation of recent Antarctic sea ice variability. Geophysical Research Letters 31: 10.1029/2003GL018732.
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.
But I keep an open mind on this. After all the science is not settled.
Regards to all