Changes in glacier length

Description of the results

South Tyrol‘s glaciers are shrinking. The figure shows the changes in glacier length over the last 100 years, during which almost all glaciers have retreated steadily. On average, all glaciers analyzed have lost about 790 m in length since 1990.

The large changes in Langtaufererferner/ Vedretta di Vallelunga in 1956/1957 (220 m) and 1962/1963 (725 m) are due to the separation of a glacier section in each year (1)(2). Once the lower part of the glacier separates from the main glacier, it is classified as dead ice only. This part is no longer included in the length measurements and there are large jumps in the length measurements of glaciers. The glaciers (Weißbrunnferner/Ghiacciaio di Fontana Bianca , Langenferner/ Vedretta Lunga, Übeltalferner/Ghiacciaio di Malavalle, Hangender Ferner/Vedretta Pendente, Westlicher Rieserferner/Vedretta di Ries occidentale) are not only becoming shorter, but have been showing a massive decrease in total glacier mass for years (3). Between 1997 and 2005, the glacier area in South Tyrol also decreased by almost 15% as a result of global warming, and by a further 19% between 2005 and 2016/17 (4).

In 2016/2017, about 83.9 km² of glaciers covered the mountains of South Tyrol. Their area corresponds to about a quarter of the Italian glacier area (5). The largest glacier in South Tyrol is the Übeltalferner/Vedretta di Malavalle in the Stubaier/Stubia Alps with about 7 km². Other important glaciers can be found in the Ortler/Ortles-Cevedale group and in the Ötztal Alps. 86% of the glaciers in South Tyrol are smaller than 1 km². In the future, South Tyrol‘s glaciers will continue to shrink and, due to their small size, many will have completely melted by the end of the 21st century (6).

Method

The Office for Hydrology and Dams of the Autonomous Province of Bolzano is responsible for glacier monitoring. Glacier length measurements are carried out by the Italian Glacier Committee (Comitato Glaciologico Italiano) and the Alto Adige Glacier Service (Servizio glaciologico Alto Adige) of the Italian Alpine Club (CAI) on behalf of the provincial office, using the method of the World Glacier Monitoring Service. The change in length of a glacier is relatively easy to measure, but is an indirect and delayed response of the glacier to a change in climate. The difference from the previous year‘s measurement gives the change in glacier length. The measurements are supplemented by observations from satellite images and reconstructions. The distance from the glacier snout to a defined point in the terrain is measured once a year. In addition, mass balance measurements are carried out on the selected glaciers Weißbrunnferner/Ghiacciaio di Fontana Bianca, Langenferner/ Vedretta Lunga, Übeltalferner/Ghiacciaio di Malavalle, Hangender Ferner/Vedretta Pendente and Westlicher Rieserferner/Vedretta di Ries occidentale in collaboration with the CGI. Ice thickness will also be measured on about 30 glaciers.

The cumulative changes in glacier length document transformation over several years and decades. In order to monitor climate change more closely through glacier changes, the mass balance, which is a direct signal of a change in atmospheric conditions, is calculated. It indicates the amount of snow and ice, measured in millimeters of water, by which a glacier grows or shrinks in a year. However, this method is more complex and very few long-term worldwide series are available .

Sectors affected

• Snow and glacier

• Water balance and water management

• Flora and Fauna

• Soil

• Ecosystem services

• Tourism

Related indicators

Further research at Eurac Research

Magazine and Dossier

• https://www.eurac.edu/en/blogs/covid-19/klimawandel-covid-19-in-zeitlupe

• https://www.eurac.edu/de/dossiers/dossier-schnee-suedtirol-alpen

Current Projects

• https://www.eurac.edu/en/institutes-centers/institute-for-earth-observation/projects/snowline4dailywater

• https://www.eurac.edu/de/institutes-centers/institut-fuer-alpine-umwelt/projects/alpwater

• https://www.eurac.edu/de/institutes-centers/institut-fuer-alpine-umwelt/projects/changelake

Scientific papers from Eurac Research

• Barandun M, Callegari M, Strasser U, Notarnicola C (2021): Towards daily snowline observations on glaciers using multi-source and multi-resolution satellite data.- Presentation/Speech at the Conference: SPIE.remote sensing | Madrid | 13.9.2021 - 17.9.2021

• Barandun M, Becker C, Warscher M, Callegari M, Notarnicola C, Mayer C, Strasser U (2021): Using close-to-daily snowline observations to derive glacier melt water contribution to total river runoff.- Presentation/Speech at the Conference: Workshop Alpine Hydrology 2021 | Obergurgel | 24.11.2021 - 26.11.2021

References

1) Consiglio nazionale delle ricerche: Bollentino del comitato glaciologico Italiano N. 0 - II Serie Parte Prima Ghiacciai 1957/1958. BCGI_8_II_1_Campagne_glaciologiche_1956_1957_160_345.pdf (glaciologia.it)

 2) Consiglio nazionale delle ricerche: Bollentino del comitato glaciologico Italiano N. 13 - II Serie Parte Prima Ghiacciai 1963. BCGI_13_II_1_Campagne_glaciologiche_1963_15_143.pdf (glaciologia.it)

3) Hydrographisches Amt Bozen (2016 und 2022): Glacierreport.

4) Universität Innsbruck / Eurac Research / Agentur für Bevölkerungsschutz, Autonome
Provinz Bozen, 2021: Ein interregionales Gletschermonitoringkonzept für die Region Südtirol-Tirol GLISTT

5) ZAMG (Zentralanstalt für Meteorologie und Geodynamik), Abteilung Brand­ und Zivilschutz ­ Autonome Provinz Bozen, Agenzia Regionale per la Prevenzione e Protezione Ambientale del Veneto (ARPAV) (Hrsg.) (2015): Das Klima von Tirol – Südtirol – Belluno. http://www.alpenklima.eu

6) Marzeion, B. (2015): Vergletscherungsprojektionen für Südtirol.- Bericht an das Hydrographische Amt der Autonomen Provinz Bozen– Südtirol.

Contact

Eurac Research: Center for Climate Change and Transformation

Data provided by: Office for hydrology and dams of the Autonomous Province in Bolzano, Roberto Dinale