200\xa0years of equilibrium-line altitude variability across the European Alps (1901\u22122100)

Manja Žebre,Neil F Glasser,Renato R Colucci,Costanza Del Gobbo,Filippo Giorgi,Adina E Racoviteanu

doi:10.1007/s00382-020-05525-7

Abstract

Mountain glaciers are key indicators of climate change. Their response is revealed by the environmental equilibrium-line altitude (ELA), i.e. the regional altitude of zero mass balance averaged over a long period of time. We introduce a simple approach for distributed modelling of the environmental ELA over the entire European Alps based on the parameterization of ELA in terms of summer temperature and annual precipitation at a glacier. We use 200 years of climate records and forecasts to model environmental ELA from 1901 to 2100 at 5 arcmin grid cell resolution. Historical environmental ELAs are reconstructed based on precipitation from the Long-term Alpine Precipitation reconstruction (LAPrec) dataset and temperature from the Historical Instrumental climatological Surface Time series of the greater Alpine region (HISTALP). The simulations of future environmental ELAs are forced with high-resolution EURO-CORDEX regional climate model projections for the European domain using three different greenhouse gas emissions scenarios (Representative Concentration Pathways, RCP). Our reconstructions yielded an environmental ELA across the European Alps of 2980 m above sea level for the period 1901−1930, with a rise of 114 m in the period 1971−2000. The environmental ELA is projected to exceed the maximum elevation of 69%, 81% and 92% of the glaciers in the European Alps by 2071−2100 under mitigation (RCP2.6), stabilization (RCP4.5) and high greenhouse gas emission (RCP8.5) scenarios, respectively.

Highlights

The European Alps have warmed twice as much as the global average between the late 19th and the early twenty-first century (Auer et al 2007; Ceppi et al 2012), and a trend of faster warming at Electronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.The 4395 glaciers currently still present in the Alps with a total area of 1806 ± 60 km2 (Paul et al 2020) are projected to lose a substantial part of their volume in the coming1 3 Vol.:(0123456789)century and many of them are expected to disappear by 2100 regardless of which emission scenario is used (Haeberli and Hoelzle 1995; Zemp et al 2006, 2007)
We present the analysis of mean summer temperature and annual precipitation, which are used as inputs for the envELA computations
Projections suggest that the warming will be stronger in the western Alps with respect to the eastern and this anomaly is evident under RCP4.5 and RCP8.5 (Fig. 3)

Summary

Introduction

Current regional and global estimates of the future evolution of glaciers in the Alps are based on models of variable complexity and rely on different climate projections. These models generally suggest a glacier volume loss of about 65–80% between the early twenty-first century and 2100 under a low greenhouse gas emission scenario (RCP2.6), 80–90% under a moderate greenhouse gas emission scenario (RCP4.5) and an almost complete disappearance of glaciers (volume loss 90−98%) under a high greenhouse gas emission scenario (RCP8.5) (Marzeion et al 2012; Radić et al 2014; Huss and Hock 2015; Zekollari et al 2019). There are socio-economic risks related to rapid changes in mountain glaciers, such as the decline of tourism (Spandre et al 2019; Steiger et al 2019), deterioration of drinking water quality (Hodson 2014), impact on livelihoods (Haeberli and Whiteman 2015; Carrivick and Tweed 2016) and hydro-electric power generation (Farinotti et al 2019)

Objectives

Results

Discussion

Conclusion