Glacier retreat in the maritime alps area

Abstract

In the southernmost tract of the Alps (Italian-French Maritime Alps), extensively covered by glaciers during the Last Glacial Maximum, about 30 small glaciers were present by the end of the Little Ice Age. The aim of this paper is to document the progressive decrease towards exhaustion of these glaciers, located at the latitude of 44° N, highlighting the factors affecting their retreat. All available data sources were investigated for this work including: the annual glaciers fluctuations record, comparative analyses of historical maps and multitemporal oblique photographs and direct surveys in the field. The history of the Maritime Alps glaciers fluctuations was thoroughly reconstructed. Stationary conditions were observed from 1896 up to the beginning of the 1930s; since then they underwent phases of withdrawal with variable intensity. In the early 1990s, only six glaciers were still present, the extent of which were all was dramatically reduced. In the past two decades, the Maritime Alps glacier fronts experienced a global retreat of about 100 m, with a sharp acceleration after 2002. Currently ice patches along cirque walls and/or semi-buried lenses of ice are still present; morphological evidence of permafrost creeping in the glacier forefield accounts for the incipient transition to periglacial landforms (i.e. rock glaciers). The main factors controlling glaciers retreat seem to have been their original extent at the beginning of the current regressive phase and their distance from the main chain divide. From a climatic point of view unfavourable factors for glaciers persistence have been in the last decades a remarkable and sharp temperature increase, a decrease in winter snowfall and a shift of the rainfall peak from autumn to spring.

Last Glacial Maximum and the Gschnitz stadial in the Maritime Alps according to 10Be cosmogenic dating

“…(Chiotas meteo station, source: Agenzia Regionale per la Protezione Ambientale, Piemonte) increases regularly from November (>10 cm) to April (>280 cm), constantly exceeds 100 cm between December and April, and typically persists on the surface until early June. It is probably because of high snowfall that some small glaciers presently survive in the Maritime Alps (Federici & Pappalardo, 2010), despite a general trend of glacial retreat elsewhere in the Alps (Maragno et al 2009;Baroni et al 2010). These peculiar characteristics also make this part of the mountain range an ideal place to test the synchroneity of the LGM in the Alps.…”

“…The present ELA of the Maritime Alps glaciers, as evaluated from six relict ice bodies in the Maritime Alps, is 2900 m a.s.l., with local controls raising and depressing it by up to several tens of metres (Federici et al 2000;Federici & Pappalardo 2010). The LIA ELA of the Gesso basin, as calculated from various reconstructed cirque glaciers, is around 2800 m a.s.l.…”

The Medieval Climate Anomaly in the Mediterranean Region

“…Long‐term climatic warming of the past century resulted in a significant retreat of southern European glaciers, which were losing 30–100% of their volume (Chueca et al, ; Grunewald & Scheithauer, ). Today, only a few small glaciers have survived in the Mediterranean region (Hughes, ), namely, in the Pyrenees, Maritime Alps (Federici & Pappalardo, ; Federici et al, ), Italian Apennines (D'Orefice et al, ), the Dinaric and Albanian Alps (Grunewald & Scheithauer, ), and the mountains of Turkey (Çiner, ; Kurter, ; Sarıkaya, ; Yavaşlı et al, ). The last glaciers in the Cantabrian Mountains completely melted during the first half of the 20th century (Serrano et al, ).…”

Little Ice Age and contemporary glacier extent in the Western and South-Western Piedmont Alps (North-Western Italy)

“…Glaciers of the Piedmont Alps have previously been investigated by Sacco (1925Sacco ( , 1927Sacco ( , 1928Sacco ( , 1932 and the Italian Glaciological Committee (Comitato Glaciologico Italiano;CGI, 1961); recently, accurate studies were carried out in the Maritime Alps by Federici, Pappalardo, and Ribolini (2003) and Federici and Pappalardo (2010), and in the Central Graian Alps by Mercalli and Cat Berro (2005).…”