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

Harry Zekollari,Daniel Farinotti,Matthias Huss

doi:10.5194/tc-13-1125-2019

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, of which the latter is to date not included explicitly 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 %, multi-model mean ±1σ) of the present-day (2017) ice volume will still be 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 (GCM), rather than by the RCM, and these differences are larger than those arising from various model parameters (e.g. flow parameters and cross-section parameterisation). 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.

Highlights

In the coming century, glaciers are projected to lose a substantial part of their volume, maintaining their position as one of the main contributors to sea-level rise (Slangen et al, 2017; Bamber et al, 2018; Marzeion et al, 2018; Moon et al, 2018; Parkes and Marzeion, 2018)
GloGEMflow consists of a surface mass balance component (Sect. 3.1), which is taken from Global Glacier Evolution Model (GloGEM) (Huss and Hock, 2015), and an ice flow component (Sect. 3.2)
We extended an existing glacier evolution model (GloGEM) through the incorporation of an ice flow component

Summary

Introduction

Glaciers are projected to lose a substantial part of their volume, maintaining their position as one of the main contributors to sea-level rise (Slangen et al, 2017; Bamber et al, 2018; Marzeion et al, 2018; Moon et al, 2018; Parkes and Marzeion, 2018). The future evolution of glaciers in the European Alps was modelled as a part of global studies, relying on methods that parameterise glacier changes through volume–area–length scaling (Marzeion et al, 2012; Radicet al., 2014) and methods in which geometry changes are imposed based on observed changes (Huss and Hock, 2015). These regional and global studies generally suggest a glacier volume loss of about 65 %–80 % between the early 21st century and 2100 under a moderate warming (RCP2.6 and RCP4.5) and an almost complete disappearance of glaciers under warmer conditions (RCP8.5)

Methods

Findings

Discussion

Conclusion