Centennial Climate Drivers of Glacier Changes in Greenland

Greenland`s ice masses are currently experiencing particularly strong changes due to human-induced climate change. The observed time series of atmospheric conditions and impacts on the glacier surface are limited to recent decades. A longer perspective is particularly important if we are to achieve realistic reconstructions of the past or modeling of the future, but is usually limited to indirect proxies. In the project `WEG_RE - Centennial Climate Drivers of Glacier Changes in Greenland` an interdisciplinary approach is taken to improve our understanding between glacier changes and the underlying climatic drivers. The project is based on archival data from the legendary expedition of the Graz-based researcher Alfred Wegener in the years 1929-1931. During this ambitious expedition climatological and glaciological data were collected, which are excellently documented and available for the project in the archives of Graz University. Climatologically, these are of particular relevance because they were at the core of a short warm phase in which air temperatures were similar to those currently observed. Moreover, they are available at a temporal resolution that is unique for the time. Almost a century later, we will therefore again monitor the same parameters over three years at exactly the same measurement sites and under similar atmospheric conditions, albeit under fundamentally different geometric boundary conditions. We will expand the monitoring to include modern methods based on artificial intelligence and innovative process studies. Using modeling and deep learning approaches, patterns will be compared and feedback mechanisms quantified on a local scale. Dynamic models are then used in a next step to perform sensitivity studies. This allows us to determine which factors are causing the observed changes and how glacier surface and atmosphere influence each other. This will give the results further spatial relevance, as the geometric configuration of the study area is representative of large parts of the Greenland ablation area. An important component of the work will also be the interaction and involvement of the Greenlandic people. We will be logistically supported by local operators and at the end of the project the results of the research will be presented in the neighboring settlements. Further outreach activities beyond the core project are already planned. The project will be a collaboration between the University of Graz, KnowCenter Graz, the University of Fairbanks, Alaska and GEUS, Denmark.

Almost a century ago, the legendary geoscientist Alfred Wegener led groundbreaking expeditions to West Greenland, meticulously documenting glaciers, weather, and snow conditions. The results remained largely unused for almost a century, not least due to his tragic passing away on the Greenland Ice Sheet in November 1930. The FWF-funded project WEG_Re set out to revisit these historical observations and combine them with modern climate science, artificial intelligence, and field measurements to understand what has changed in one of the world's most climate-sensitive regions. Greenland sits at the heart of global climate dynamics. Its ice sheet holds enough water to raise global sea levels by over seven meters, and the Arctic is warming roughly four times faster than the global average. Understanding how the interaction between Greenland's ice and atmosphere has evolved over the past century is essential for projecting climate evolution globally. The WEG_Re project, centered at Graz University, retraced Wegener's routes in West Greenland, recovering historical data and combining it with modern satellite observations, automatic weather stations, and state-of-the-art reanalysis datasets. A key finding: large-scale atmospheric circulation patterns play a decisive role in driving Greenland's warming periods - including the dramatic warming observed in the early 20th century, which bears striking resemblance to recent decades. This suggests that both natural variability and human-induced climate change are shaping the Arctic in ways that historical records can help us decode. The project also explored how artificial intelligence can help bridge the gap between sparse historical observations and the dense data sets of modern climate science. Machine learning tools were applied to identify connections between large-scale atmospheric drivers and local glacier behaviour - an approach that holds promise well beyond Greenland. Also, the project highlights the value of short-term (historical) observation time series for bias-correcting reanalysis products. As a complementary, opportunistic outcome, WEG_Re documented the formation, extent and decay of aufeis - extensive seasonal ice formations in glacier forefields that play an understudied but important role in local hydrology and ecosystems. Field expeditions to Uummannaq and Qaamarujup Sermia provided ground truth data and allowed for connecting it to longer time scales. The project generated and contributed to several peer-reviewed publications, dozens of conference presentations at leading international venues, and a remarkable public footprint: from an ARD television documentary reaching millions of viewers, to school talks delivered in Austria and Greenland, to interviews on Austrian public radio. Science communication was an integral and important pillar of the project that we intend to expand upon.