Several "Gore"-ites have used a story from the G&M about the Ayles Ice Shelf breaking off as a partisian attack on the governing CPC and the Gov'ts response to the trendy global warming debate.

The sea-ice ice shelves began to form at about 4.5 kilo-annum (ka,10³ years) (before the present, present defined by geochronologists as A.D. 1950) during a middle Holocene climatic deterioration.

Prior to that, the Pleistocene glaciers had retreated to behind their present positions, the summer sea-ice cover was much less severe with predominantly open water compared with modern conditions, and no ice shelves were present (Evans and England, 1992).

The timing of glacier readvance and formation of the glacial [sic, glacier] ice shelves and the glacier component of the composite ice shelves is more difficult to ascertain. Some large glaciers are still advancing in response to the middle Holocene climatic deterioration, and some glaciers display evidence of dual advances, which may reflect both the middle Holocene and "Little Ice Age" (400-100 years before present) accumulations (Evans and England, 1992).

GLACIERS OF THE ARCTIC ISLANDS ELLESMERE ISLAND ICE SHELVES AND ICE ISLANDS, MARTIN O. JEFFRIES, Glaciers of North America - GLACIERS OF CANADA, U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1386-J-1, J147-J163

Now, while this is a signifcant event, I think any conclusions based on the article are a little premature, another example of looking out the window and calling it climate. The G&M notes that Dr. Warwick Vincent of Laval who in 10 years of studying the Artic flows had never seen it's like. That is true. Nothing as signifcant has happened in ten years. However, if you look back a little farther, you can see that significant events happen to the ice shelves (sea, glacial or composite) on a regular basis.

As noted in the article, the amount of ice in the ice-shelves in only about 10% of what they were in 1905. In fact, from Point Moss on the north coast of Ellesmere down the west coast to the Ice Plug in Nansen Sound is estimated to have been one gigantic ice shelf. Arctic ice shelves are composed of three distinct types of ice. Glacial, sea and composite ice. All that means is where the majority of the ice comes from. In Antarctica, the ice shelves are mainly glacial-fed ice.

The largest observed ice island calving occurred at Ward Hunt Ice Shelf (Fig. l), where almost 600 km2 of ice broke away at some time between August 1961 and April 1962 (Hattersley-Smith, 1963

"Ice Island Calvings and Ice Shelf Changes, Milne Ice Shelf and Ayles Ice Shelf, Ellesmere Island, N.W.T.", MARTIN O. JEFFRIES, ARCTIC, VOL. 39, NO. 1 (MARfloat: ;CH 1986) P. 15-19

In his paper, Jefferies lays out the ground-work to explain last years fracturing of the the Ayles Ice Sheet:

During the period 1959-74 some 48 km2, involving 3.3 km3, of ice calved from Milne and Ayles ice shelves and the remainder of Ayles Ice Shelf moved some way out of the mouth of Ayles Fiord. Although the total loss of ice from these events is much less than the massive loss from Ward Hunt Ice Shelf, it still constitutes a considerable loss, indicating the ice shelves remain unstable and prone to disintegration.

The movement of the Ayles Ice Sheet some 5 kilometers into the Artic Ocean spelled it's impending distruction.

In a paper contributed to by the G&M's quoted scientist, Ice-shelf collapse, climate change, and habitat loss in the Canadian high Arctic, Polar Record 37 (201): 133-142 (2001), W. F, Vincent, J.A.E. Gibson, and M.O. Jeffries is a table examining the amount of ice based on the estimated control of the 1906 survey.

Year	Area		Source
	km²	% 1906
1906	2327	100.0	Bushnell (1956)
1954	1422	61.1	Crary (1956)
1962	906	38.9	Hattersley-Smith (1963)
1985	644	27.7	Jefferies and Serson (1983)
1998	490	21.1	present study

As this table indicates, the vast majority of ice shelf loss occured in the first half of the 20th century, assuming there's been no difference in the Helocene ice shelves. from 4500 years ago to 100 years ago. To me, that's a significant assumption.

Even moreso, it isn't exactly something that you can bring to bear on a government that has been in power for almost a year.

Partisian blogging . . . apparently a place where facts hurt and global conditions don't apply.

Cheers,
lance

Update:BigCityLib's rebuttal.

Posted at: 18:54 | Comments (2) | [misc] | G