There's ice thousands of years old in the Velebit Caves: 'Somewhere it's completely gone'

A two-week speleological expedition in Northern Velebit National Park has concluded with findings indicating that glaciers and perennial ice formations within the area, some estimated to be thousands of years old, are showing signs of melting and disappearance. The research team documented changes in microclimates and ice levels during their exploration of 33 caves, revealing that while winter temperatures remain extremely low, certain areas have experienced reductions in both the quantity and elevation of permanent ice. The expedition took place in one of Croatia’s coldest locations this summer, according to reports from the Speleological Department of PDS Velebit and the Committee for Speleology of the Croatian Mountaineering Association. They noted that the lowest recorded temperature last year was approximately -22 degrees Celsius at one location, reinforcing the park's status as one of the country’s most frigid spots. Despite these cold conditions, researchers observed variations in ice levels, including instances where the ice had completely vanished. According to preliminary data collected during the expedition, the microclimate conditions in the caves remain unique, allowing snow to persist even into August in some parts of the Hajdučki Kukovi region. This phenomenon highlights the distinct environmental characteristics of Northern Velebit. However, experts caution that despite the cold winters, which help preserve these microclimates, the underground environment is still vulnerable to the effects of climate change. Dalibor Paar, from Zagreb’s Faculty of Science, emphasized that in some caves, the level of perennial ice has dropped significantly, and in certain cases, the ice has disappeared entirely. His comments underscore the growing concern over how global warming might affect even the most remote and seemingly stable environments. The expedition explored 33 speleological sites with a total depth of around 1,100 meters, expanding existing knowledge about previously studied caves. A total of 51 spelunkers from ten different speleological clubs participated, representing countries such as Croatia, Austria, the United States, Portugal, and Bosnia and Herzegovina. Their work focused on monitoring changes in microclimatic conditions within the caves and examining the relationship between deep underground systems and surface ecosystems. Ema Buljan, who led the expedition alongside Olga Jerković Perić from the Speleological Department of PDS Velebit and the Committee for Speleology of the Croatian Mountaineering Association, stated that the gathered information will contribute to a better understanding of the impact of climate change on both subterranean and above-ground ecosystems within the national park. These findings could also be used to develop educational materials highlighting the natural values of Croatia. The expedition received support from Northern Velebit National Park, which recognized the importance of studying these unique geological features. Researchers hope that the data will provide insights into long-term environmental trends and inform conservation strategies for preserving the delicate balance of the region’s ecosystems. The findings from the expedition add to a growing body of evidence suggesting that even the most isolated and ancient ice formations are not immune to the pressures of a changing climate. As scientists continue to monitor these developments, they emphasize the need for ongoing research and international collaboration to address the challenges posed by global warming. The expedition’s results highlight the urgency of protecting these fragile environments, as the loss of ancient ice formations could have far-reaching consequences for local biodiversity and ecological stability. Scientists are already planning further studies to track the evolution of these changes over time.