The state of Italian glaciers: a snapshot of the 2006-2007 hydrological period

In this study, we present a snapshot of Italian glaciers that outlines the hydrological years of 2006 and 2007 and was derived from the interpretation of high-resolution orthophotographs. The results are freely available and downloadable on the website of the Italian Glaciological Committee (http://www.glaciologia.it/). Considering that glacial resources are suffering the effects of an extreme degree of ongoing climate warming, glacier monitoring requires homogeneous and accurate contemporary surveying approaches to realize the effective management of multi-temporal glacier inventories in GIS environments. Furthermore, the diffuse and rapid withdrawal of glaciers requires the use of multi-temporal, repeatedly updated data acquired with the same instruments during the same time interval. In this work, the data collected were organized and processed using the orographic setting of the Alps (International Standardized Mountain Subdivision of the Alps, ISMSA-SOIUSA) rather than local and regioal administrative boundaries within which glaciers are placed (regions and provinces). The conducted survey allowed us to evaluate the distribution of Italian glaciers (969 including the two small Apennine glacierets of Calderone in the Gran Sasso Massif), which covered an area of 387.4 km2 ± 2%. The most glaciated mountain group is the Ortles, with 134 glaciers covering an area of 76.5 km2, whereas the Alpi Marittime hosts only one small glacier (0,041 km2). New data, which until now have never been published in Italian inventories, refer to the extension of the glacial debris cover (> 46 km2, equivalent to 12% of the whole glaciated surface in 2006-2007). Debris cover was outlined on 614 glaciers, corresponding to 63% of all surveyed glacial units. The comparison of our data with those recorded in the first systematic glacier inventory of the Italian Alps (CGI 1959-1962) shows that in 2006-2007, 181 glaciers were completely extinct, 470 glaciers remained unitary, and 171 bodies were fractionated to generate 243 new glaciers. As a consequence of recent glacial retreat and the induced fractionation of glacial bodies, the total number of glaciers increased (+ 147 glaciers), whereas the surface decreased by ca. 140 km2 (-27%). This work represents a breakthrough in the availability of glaciological data from the Italian Alps collected over a very short time period. This study will also satisfy the rising demand of open source availability of environmental data pertaining to mountainous regions.