Modelling the future evolution of glaciers in the European Alps under the EURO-CORDEX RCM ensemble

Abstract

Abstract. Glaciers in the European Alps play an important role in the hydrological cycle, act as a source for hydroelectricity and have a large touristic importance. The future evolution of these glaciers is driven by surface mass balance and ice flow processes, which the latter is to date not included in regional glacier projections for the Alps. Here, we model the future evolution of glaciers in the European Alps with GloGEMflow, an extended version of the Global Glacier Evolution Model (GloGEM), in which both surface mass balance and ice flow are explicitly accounted for. The mass balance model is calibrated with glacier-specific geodetic mass balances, and forced with high-resolution regional climate model (RCM) simulations from the EURO-CORDEX ensemble. The evolution of the total glacier volume in the coming decades is relatively similar under the various representative concentrations pathways (RCP2.6, 4.5 and 8.5), with volume losses of about 47–52 % in 2050 with respect to 2017. We find that under RCP2.6, the ice loss in the second part of the 21st century is relatively limited and that about one-third (36.8 % ± 11.1 %) of the present-day (2017) ice volume will still present in 2100. Under a strong warming (RCP8.5) the future evolution of the glaciers is dictated by a substantial increase in surface melt, and glaciers are projected to largely disappear by 2100 (94.4 ± 4.4 % volume loss vs. 2017). For a given RCP, differences in future changes are mainly determined by the driving global climate model, rather than by the RCM that is coupled to it, and these differences are larger than those arising from various model parameters. We find that under a limited warming, the inclusion of ice dynamics reduces the projected mass loss and that this effect increases with the glacier elevation range, implying that the inclusion of ice dynamics is likely to be important for global glacier evolution projections.

On the Imbalance and Response Time of Glaciers in the European Alps

“…(a) Evolution of volume over time. The black line is the actual glacier evolution between 1990 and 2018 (modelled by Zekollari et al, ), while the colored lines indicate the committed evolution. (b) Relative (dark grey) and absolute (light grey) committed volume loss for a given year.…”

“…Here, we use a novel glacier evolution model (Zekollari et al, ) that explicitly accounts for surface mass balance (SMB) and ice flow processes, to quantify the temporal evolution of the committed glacier loss in the European Alps. Through various numerical experiments, we aim at shedding light on the evolution of the glacier‐climate imbalance over time and its link to the glacier response time.…”

Formation and future evolution of glacier lakes in Austria (FUTURELAKES)

“…This projected trend of glacier melt however represents a decrease of glacier melt compared to the most recent trends and thus a slow down in emergence of ice-free area (Figure 14). The authors also acknowledge this discrepancy to measured data and relate this to stagnant ablation areas and disconnected ice patches that are included in glacier inventories, but cannot be reproduced in their models (Zekollari et al, 2018). The resulting difference would preserve glaciers in the Austrian Alps until the late 21 st century (Table 6).…”

“…The linear prognosis refers to a continuation of glacier retreat applying the mean melt rate between 2006 and 2015. Other scenarios of glacier melt are taken from Zekollari et al (2018). 31 Figure 15 Lake Sulzsee in Obersulzbachtal, Hohe Tauern.…”

“…Assuming a similar mean lake size of 12,000 m², which formed on average between 2006 and 2015, we would have to expect another 200 lakes within the remaining glacier area of 2015. Fischer et al (2015a) In a different approach we applied scenarios of glacier decrease taken from Zekollari et al (2018). They modelled the future evolution of glaciers in the European Alps for three climate scenarios (RCP 2.6, RCP 4.5, RCP 8.5) based on glacier changes between 2008 and 2017 using a modified ice-thickness model evolved from the HF approach.…”