Brief communication: Do 1.0, 1.5, or 2.0 °C matter for the future evolution of Alpine glaciers?

Loris Compagno,Sarah Eggs,Matthias Huss,Daniel Farinotti,Harry Zekollari

doi:10.5194/tc-15-2593-2021

Abstract

Abstract. With the Paris Agreement, the urgency of limiting ongoing anthropogenic climate change has been recognised. More recent discussions have focused on the difference of limiting the increase in global average temperatures below 1.0, 1.5, or 2.0 ∘C compared to preindustrial levels. Here, we assess the impacts that such different scenarios would have on both the future evolution of glaciers in the European Alps and the water resources they provide. Our results show that even half-degree differences in global temperature targets have important implications for the changes predicted until 2100, and that – for the most optimistic scenarios – glaciers might start to partially recover, owing to possibly decreasing temperatures after the end of the 21st century.

Highlights

Climate change is one of the largest challenges that society will face during this century
While there is overwhelming consensus that decisive action has to be taken to limit the unwanted consequences of ongoing climatic change (UN, 2015; IPCC, 2018; IPBES, 2019; IPCC, 2019; WEF, 2020), the debate around which temperature targets to pursue is all but settled
We quantified the impact that a global temperature change of +1.0, +1.5, or +2.0 ◦C compared to preindustrial levels would have on glaciers of the European Alps

Summary

Introduction

Climate change is one of the largest challenges that society will face during this century. Put forward in 2015 and adopted by 196 parties, the Paris Agreement concurred that such a threshold is “well below 2 ◦C above preindustrial levels”, and that efforts should be pursued to “limit the temperature increase to 1.5 ◦C” (UN, 2015) Even under these ambitious climate targets, important environmental changes, such as changes in water availability, migration of species, or glacier loss, are expected to occur. For the upcoming 26th United Nations Climate Change Conference of the Parties, for example, emphasis is put on separating the impacts occurring under scenarios of 1.0, 1.5, and 2.0 ◦C of warming above preindustrial levels In this brief communication, we focus on the differing impacts that such scenarios would have on glaciers and related water resources in the European Alps. We consider projections until the year 2300, albeit acknowledging that large uncertainties exist when doing so

Data and methods

Results and discussion

Conclusions