Before Caspar Ammann started playing for the Team, he was a geologist who wrote the following serviceable discussion of glaciation in the “dry” Andes between 19 and 27S (Quelccaya is at 12S).
Under current climatic conditions, no glaciers can exist in the high Andes of the Western Cordillera in the high Andes of the Western Cordillera between 19 and 27 S. The annual mean temperatures in the highest peaks are far below freezing but the extremely dry conditions make any glacial development impossible. With increasing summer precipitation towards the tropics, persistent snowfields are more frequent and at 18 30′S the first glacier appears (Volcano Guallatiri) In the southern region, first glaciers appear under sharply increased wintertime precipitaiton south of 27S. Between these two regimes, the South American Dry Diagonal crosses the Andes from the northwest to the southeast.
What does that mean for glaciation at Quelccaya? It might not mean anything. But it’s interesting that the glaciers in the region are on a macro scale precipitation-limited.
When I see a rather good geologically-based article by Ammann, it’s too bad to see him writing such statistical bilge with his co-author Rev. Wahl. He should have stuck to being a geologist.
Now that I think about it, for all the criticism from the Team about me being an “amateur”, neither Ammann nor Wahl is a statistical specialist. Ammann studied as a geologist and Wahl took economics and theology cv here. He has some theological material on the internet.
Ammann et al 2001, PPP 172, 313-326 http://www.glaciologia.cl/textos/amman.pdf