The evolution of the Italian glaciers from the previous data base to the New Italian Inventory. Preliminary considerations and results

Abstract

A glacier inventory is a fundamental tool for describing and managing the Alpine glacierized environment and evaluating the impacts of the ongoing climate change. After the 1959-1962 Italian glacier inventory published by the Italian Glaciological Committee (CGI) in cooperation with the National Research Council (CNR), only regional glacier lists have been developed in Italy, thus giving partial pictures of the evolution of the Italian glaciers. In this work, we summarized the main results from the New Italian Glacier Inventory, a national glacier atlas recently completed and based on the analysis of high resolution color orthophotos which were acquired in the time frame 2005-2011. In the New Italian Glacier Inventory 903 glaciers are described, covering a total area of 369.90 km² ± 2%. The largest part of the glacier coverage is located in the Aosta Valley Autonomous Region (36.15 % of the total), followed by the Lombardy Region (23.71 %) and the Autonomous Province of Bolzano (23.01 %). The highest number of glaciers was found in Lombardy (230), then in the Autonomous Province of Bolzano (212), in the Aosta Valley Autonomous Region (192), and in the Autonomous Province of Trento (115). About 84 % of the census is composed by glaciers minor than 0.5 km² covering only the 21% of the total area. Glaciers wider than 1 km² are 9.4 % of the whole number, but they cover 67.8 % of the total area. In the widest size class (>10 km²), only three glaciers are found. Only 25 glaciers (2.8 % of the census) were classified as “valley glacier”, while the largest part (57.3%) was classified as “mountain glacier” and “glacieret” (40%), thus underlining that the Italian glaciers are spread into several small ice bodies with few larger glaciers. A first comparison between the total area reported in the New Italian Glacier Inventory and the value reported in the CGI –CNR Inventory (1959-1962) suggests an overall reduction of the glacier coverage of about 30% (from 526.88 km² in the Sixties to 369.90 km² in the present time). A second comparison was performed with the WGI (World Glacier Inventory) dataset which in the Eighties listed 1381 Italian glaciers covering a total area of 608.56 km₂. This comparison suggests a loss of 478 glaciers and an area reduction of 238.66 km² (-39 %).