the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 24 Mar 2026
On thin glacial ice: New Austrian Glacier Inventory shows accelerating glacier shrinkage and 31% area loss within two decades
Abstract. We present the new Austrian glacier inventory, AGI 5. Glacier outlines were manually digitized from high-resolution orthoimagery and digital elevation models (DEM), using older inventory data as a baseline. The delineation of debris-covered ice was supported by visual analysis of multi-temporal imagery and DEM differencing, depending on data availability. We assessed discrepancies with older inventories and differences in interpretation between analysts using a round robin experiment (mapping of selected glaciers by several analysts). The updated inventory reflects glacier extent in 2023 (55 % of total glacier area in the study region), 2022 (43 %), and 2021 (2 %). The total glacier area in AGI5 is 285±12 km2. Most glaciers in Austria (87 %) are smaller than 0.5 km2. These "very small" glaciers comprise 22 % of the total glacier area. Nine glaciers remained larger than 5 km2 and account for more than a quarter of Austria's glacierized area. Area losses since the previous inventory (2004–2012) amount to 129±23 km2, corresponding to 31 % of the total glacier area. Median area loss rates differ between regions, ranging from 2–3 % per year in more heavily glacierized regions to almost 7 % per year in regions with smaller glaciers. Of 894 glaciers listed in the previous inventory, 95 have disappeared completely or were no longer mappable. Compared to other glacierized regions, Austria's glacier recession since the Little Ice Age (LIA) maximum is well constrained with a LIA inventory, four high-resolution, consistent AGIs from 1969 to 2022/23, and additional coverage in complementary inventories using different data sources. As glacier loss accelerates, more frequent updates to the AGIs are needed to keep pace with rapid changes.
Competing interests: At least one of the (co-)authors is a member of the editorial board of The Cryosphere.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.- Preprint
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Status: open (until 30 Jun 2026)
- RC1: 'Comment on egusphere-2026-1241', Anonymous Referee #1, 20 Jun 2026 reply
Data sets
The Austrian Glacier Inventory GI 5, 2021-2023, as vector files [dataset] Hartig et al. https://doi.pangaea.de/10.1594/PANGAEA.991106
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This is a thorough, detailed and well written design and description of the new Austrian Glacier Inventory (AGI5).
I question the value of 10-25cm orthophotography for glacier mapping - one could not identify extent to this precision even if one was in situ, and with summer melt, it would change on a daily/weekly basis - these images were captured over two summers (2022-23). However this is the resolution of the available imagery !
The round robin experiment is curiously interesting but I note that the analyst variability far exceeds the image resolution.
I identify some very minor graphic issues in the otherwise excellent figures:
Figure 1: there is no need to add 0' in each graticule label - this is simply 'noise'
Figure 7: it seems inconsistent to shorten the labels on the Vanishing Glaciers to GI3,GI5 when even in the caption, they are written in full: AGI3, AGI5 etc..
Supplementary material: the scale bar divisions on figures should be standard/round numbers e.g. 50,100 rather than 40, 45, 0.45, 0.26, 70 etc.. (figures S1,2,4,5,9)