Comment on this excursion by Allan Maguire

My comment regarding the ice age wind is that I have read in Scientific American when discussing conditions during the last ice age. The wind in the northern hemisphere was cold and dry and of much greater strength than now. In addition a research report by Professor Archer of Sydney University on ice age conditions in Australia indicates that we had no glaciers on the mainland, and refers to the howling cold winds which stripped surface soil and caused loss of two thirds of trees, and terrible loss of plant and animal life.

The previous warm wet climate referred to by Noel, according to my reading, ended after Australia broke away and Antarctica and started to freeze because of the change of climate when a circumpolar current arose to shield Antarctica from warm tropical water.

At such a gathering it was inevitable there would be mention of global warming. On two occasions Noel remarked on the Milankovitch hypothesis without much further discussion.

I thought it would be of interest to set out a reference to this.
The most recent ice age had thick ice as far south as Switzerland in Europe and to Wisconsin in USA. Vancouver Canada was covered with one mile thick ice.

The Ice Ages recur at about 100,000 year intervals as revealed by ice cores and also cold-loving marine animals. The occurrence of ice ages is governed by a combination of factors as revealed by the Milankovitch hypothesis. This deals with the orbital geometry of the earth – a 100,000 year cycle around the sun, a ’tilt ‘cycle of 42,000 years, a ‘wobble’ cycle of 23,000 years. A fuller description can readily be seen in an encyclopedia.

For further information

Nature July 31, 1997 ‘A Warm Future in the Past’ William R Howard of University of Tasmania.
Australasian Science Vol 25/7 August 2004. ‘The Day after Tomorrow’ Kershaw and Turney.
Both of these references list curves for ice ages (only Howard has ice volume) during the past 500,000 years. The curves show every ice age is very different from each other. Howard selects the interglacial of the past 423,000 to 362,000 years as having the similar orbital geometry to the present. It was a long hot interglacial and he suggests it may be a model for our time. Both authors remark on the unknown effect of CO2.


Double Creek nature track. This was an example of wet and dry slerophyl forest, first a section at creek level was followed by a higher level track with some impressive large trees. It was obvious that all nature walks including the one across the border at Nagee were showing the effects of the long period below average rainfall.

Supplied by Allan Maguire, Sale & District FNC.