The Adamello Glacier (Central Alps): areal and volumetric variation since the Little Ice Age

More than 140 glaciers developed during the Little Ice Age on the Adamello - Presanella Group covering an area almost the double of their present surface.Since the middle of the 19th Century there was an important reduction in thickness and area extension of glacier bodies, broken by brief and weak advances, the most recent of which is around the 1980 AD. Here we present new data on both areal and volumetric Holocenic variations of the Adamello Glacier, the widest glacier of the Italian Alps. Through detailed geomorphological and glacial geological field surveys aided by photointerpretation, we reconstructed the Little Ice Age glacial limits; areal variations occurred in the 20th and 21th Centuries have been inferred from historical maps and multitemporal aerial photographs. On the basis of detailed maps, precisely dated positions of the front of the Adamello glacier have been reconstructed and used for checking the time-distance curve obtained from annual glaciological surveys (conducted since the beginning of the 20th Century by the Italian Glaciological Committee). All the collected data have been georeferenced and managed using a GIS for evaluating the most relevant quantitative parameters. Data on mass balance variations show that the Adamello glacier lost about 60% of its volume in 160 years (between LIA and 2007 AD) and about 30% in only 30 years (between 1982 and 2007). Data collected allow us to estimate the amount of ice melting as a consequence of global warming and evaluating future availability of melt-water.