Potential future lakes from continued glacier shrinkage in the Aosta Valley Region (Western Alps, Italy)

Abstract

Aosta Valley (Western Alps, Italy) is the region with the largest glacierized area of Italy. Like other high mountain regions, it has shown a significant glacier retreat starting from the end of the 'Little Ice Age' that is expected to continue in the future. As a direct consequence of glacier shrinkage, glacier-bed overdeepenings become exposed, offering suitable geomorphological conditions for glacier lakes formation. In such a densely populated and developed region, opportunities and risks connected to lakes may arise: 1) economic exploitation for hydropower production, tourism and water supply; 2) environmental relevance for high mountain biodiversity and geodiversity; 3) potential risks due to outbursts and consequent floods. In this study, the locations of potential future glacier lakes over large glacierized areas (183 glaciers covering 163,1 km 2) of Aosta Valley were assessed by using the GlabTop2 model. 46 overdeepenings larger than 10,800 m 2 were identified, covering an area of 3.1 ± 0.9 km 2 and having a volume of 0.06 ± 0.02 km 3. The majority of the overdeepenings are located in the Monte Rosa-Cervino massif and a mean depth b10 m characterizes them. Moreover, an estimation of the most recent total ice volume for the Aosta Valley was provided (5.2 ± 1.6 km 3 referred to 2008). Thanks to the validation by the proposed "backward approach" and GPR (Ground Penetrating Radar) data, we can confirm that the location of the overdeepenings is robust while their actual dimensions are subject to considerable uncertainties. Almost all of large lakes (area N 10,000 m 2), potentially the most dangerous, are modelled. Finally, we suggest choosing medium pixel size (about 60 m) of the DEM in order to obtain, at least, the location of the largest lakes and to avoid overestimations of ice thickness and thus a great number of false positive overdeepenings. The results presented here can be useful for understanding how the alpine environment will look in the future and can help the management of water resources and risks related to glacier lakes.

Fieldtrips and Virtual Tours as Geotourism Resources: Examples from the Sesia Val Grande UNESCO Global Geopark (NW Italy)

“…In the present context of climate change, high-altitude geotrails are essential for raising awareness among the general public of ongoing environmental changes, and the glacial and periglacial areas offer some of the best evidences of these developments (e.g., glacier shrinkage, new glacier lakes formation, permafrost degradation [91,114,118]). Moreover, high altitude geotrails could also contribute to the explanation of the indirect effect of climate change on human settlements in mountain areas (eg., ski resorts, water supply, mountain huts access), and allow to test the fruitor perception about the environmental resources related to climate changes [126].…”

“…The glaciological trail of the Upper Sesia Valley Natural Park has been recently included among the glaciological itineraries on the Italian glacial mountains [90,91]. The contents of the trail drive the attention of the geotourists to some of the most important topics of the present-day debate on environmental changes of the glacial environments [114].…”

An integrated approach to investigate climate-driven rockfall occurrence in high alpine slopes: the Bessanese glacial basin, Western Italian Alps

“…The highest ice losses occurred in the lowest part of the western lobe, where the glacier surface lowered of about 35 m, and in most of the accumulation area, where the surface elevation change was about 20-30 m. On the contrary, losses in the order of 10-20 m are found along the western margin of the accumulation area of the glacier, likely because of snow avalanche feeding from the Bessanese NE face. Even lower values can be found in the portion of the glacier located immediately below the 2010 front limit: this area is steeper than the rest of the glacier, and thus ice here was presumably thin (Linsbauer et al 2012;Viani et al 2020) and rapidly thawed away, causing the 1990s glacier tongue to separate from the accumulation area in the years 2000s. For the period 1991-2011, the cumulative glacier thickness changes measured by the CGI operator at two benchmarks located at 2950 and 2877 m a.s.l.…”

Toward Numerical Modeling of Interactions Between Ice-Marginal Proglacial Lakes and Glaciers

“…Examples of studies documenting increasing number and area of proglacial lakes from other regions of the world include southern Iceland (Schomacker, 2010;Guðmundsson et al, 2019), western Greenland (Carrivick and Quincey, 2014), central Tibet (Wang et al, 2013), Austria (Buckel et al, 2018) and south America (Wilson et al, 2018;Emmer et al, 2020). The prevalence of proglacial lakes will continue as glacier overdeepenings become ice-free and fill with meltwater (e.g., Magnin et al, 2020;Viani et al, 2020). Proglacial lakes can be ice-marginal (or else situated beyond an ice margin) and impounded by ice, debris or bedrock.…”