Geomorphic influence on small glacier response to post‐Little Ice Age climate warming: Julian Alps, Europe

Abstract

The evolution of glaciers and ice patches, as well as the equilibrium‐line altitude (ELA) since the Little Ice Age (LIA) maximum were investigated in the Julian Alps (south‐eastern European Alps) including ice masses that were previously unreported. Twenty‐three permanent firn and ice bodies have been recognized in the 1853 km2 of this alpine sector, covering a total area in 2012 of 0.385 km2, about one‐fifth of the area covered during the LIA (2.350 km2). These features were classified as very small glaciers, glacierets or ice patches, with major contribution to the mass balance from avalanches and wind‐blown snow. Localized snow accumulation is also enhanced in the area due to the irregular karst topography. The ice masses in the region are at the lowest elevations of any glaciers in the Alpine Chain, and are characterized by low dynamics. The ELAs of the two major LIA glaciers (Canin and Triglav) have been established at 2275 ± 10 m and 2486 ± 10 m, respectively, by considering the reconstructed area and digital elevation model (DEM) and using an accumulation area ratio (AAR) of 0.44 ± 0.07, typical of small cirque glaciers. Changes in the ELA and glaciers extension indicate a decoupling from climate. This is most evident in the smallest avalanche‐dominated ice bodies, which are currently controlled mainly by precipitation. The damming effect of moraine ridges and pronival ramparts at the snout of small ice bodies in the Julian Alps represents a further geomorphological control on the evolution of such ice masses, which seem to be resilient to recent climate warming instead of rapidly disappearing as should be expected. Copyright © 2016 John Wiley & Sons, Ltd.

Projected effects of temperature changes on the Italian Western Tauri glaciers (Eastern Alps)

“…For mountain glaciers with lengths ≤ 1 km, surface area reductions far >60% are expected. These area losses lead to a general fragmentation into smaller units with consequent acceleration of the retreat rate, given the positive feedback due to thermal radiation from now ice-free terrain observed at the snout of some glaciers (Comitato Glaciologico Italiano, 1981-2016 and to the decrease in glacier albedo caused by several years with negative mass balance (Paul and others, 2005;Haeberli and others, 2007). The expected length reduction obtained from the linear model (Fig.…”

“…Among these 26 glaciers, none is in the potentially favourable situation to be avalanche-fed at sites that are radiation-protected and at low elevation and thus sensitive to increasing winter precipitation. The interaction of these negative feedbacks described by Huss and Fischer (2016) for the Swiss Alps, by Colucci (2016) and Carturan and others (2013a) in the Julian Alps and by DeBeer and Sharp (2009) for the Monashee Mountains (Canada) counteracts the glacier decay. Although almost all presented glaciers are avalanche-fed, the southern exposure makes the survival of some of these glaciers impossible.…”

“…Areas in 2008 are from Smiraglia and Diolaiuti (2015). The lengths in 2015 have been obtained from field measurements (Comitato Glaciologico Italiano, 1981-2016 starting from 1982 lengths. α is the angle between the glacier surface and the horizon.…”

Quaternary glaciation in the Mediterranean mountains: a new synthesis

“…Small glaciers are present today in the mountains of Slovenia (Colucci 2016;Del Gobbo et al 2016), including on the highest peak of Triglav (2864 m Hughes 2014). The glacial record of Slovenia is still poorly dated -as noted in the review by Ferk et al (2015) in this volume -although a few ages were presented over a decade ago in Bavec et al (2004) from the glaciated Soča valley.…”

“…These can be divided into studies that focus on the Late Pleistocene geomorphological record, which is well preserved on mountains such as Velebit (Belij 1985;Bognar et al 1991;Velić et al 2011, Bočić et al 2012 and Risnjak (Bognar and Prugovečki 1997). Other researchers also recognize much larger Middle Pleistocene glaciations that even reached offshore (Marjanac & Marjanac 2004, 2016Marjanac 2012). The latter studies highlight the rich body of sedimentological evidence exposed at the present coast, including sites such as Novigrad More, where glacial deposits are visible in section.…”