glenglat: a database of global englacial temperatures

Abstract. Measurements of englacial temperatures have been collected since the earliest years of glaciology, with the first measurements dating back to the mid-19th century. Although temperature is a defining characteristic of any glacier – and is notoriously laborious to collect – no effort had been made yet to gather all existing measurements. In an attempt to make existing ice temperature data more accessible, we present glenglat, the global englacial temperature database compiled from 316 literature sources and 12 data submissions and composed of 1 931 831 measurements of depth and temperature from 788 boreholes located on 213 glaciers outside the ice sheets. Alongside recent compilations for the ice sheets (Løkkegaard et al., 2023; Vandecrux et al., 2023), most published englacial temperature measurements are now readily available to the research community. Here, we review the variety of glacier thermal regimes that have been measured and summarize the spatial, temporal, and climatic coverage of measurements relative to the global glacierized area. Measurements of cold and polythermal glacier ice greatly outnumber those of temperate ice. Overall, temperature has been measured in fewer than 1 ‰ of all glaciers, and only 27 % of boreholes have been measured more than once, highlighting the great potential to investigate changing temperature conditions by repeating past measurements. The database is developed on GitHub (https://github.com/mjacqu/glenglat, last access: 7 April 2024) and published to Zenodo (https://doi.org/10.5281/zenodo.11516611, Welty et al., 2025). It consists of four relational tables and detailed machine-actionable and human-readable metadata. The GitHub repository also provides submission instructions (including a spreadsheet template and validation tools), in the hope that investigators will help us keep glenglat complete and current going forward. We hope that glenglat will improve our understanding of glacier thermal regimes, refine glacier thermodynamic models, and give insight into hazardous glacier instabilities in a warming world.