Ortles: after 7000 years, the glacier moves

Thanks to an international study published in The Cryosphere and conducted with scientists from Ca’ Foscari and the Institute for the dynamics of environmental processes of the National Research Council (CNR-IDPA), it was found that the deepest and oldest ice on Mount Ortles (3,905 m, on the eastern Alps), has started moving for the first time since the time of the Similaun Man, 7000 years ago.

The first ice cores extracted indicate that the highest glacier in South Tyrol has started a phase of acceleration of unprecedented movement in the observed period. Tests are from the deeper layers, using carbon 14 technique, and from measurements conducted in the drilling hole using an inclinometer, an instrument that can detect even minimal glacial movements.

"These ice cores offer a unique opportunity to study the characteristics of the atmosphere when the Similaun Man lived in this region, so we can also learn about the environment and the climate in which he was immersed", says Carlo Barbante, professor at the Department of Environmental Sciences, Informatics and Statistics and director at IDPA-CNR of Venice.

The rapid melting of the ice is linked to global warming. "The glaciers are retreating fast because of the intense fusion linked to atmospheric warming", adds Paolo Gabrielli, a researcher at the Byrd Polar and Climate Research Center at Ohio State University, and also head of this research. "Our findings have highlighted the action of a new process that could accelerate the flow of glaciers, even at higher altitudes, helping to speed up the retreat. With the Ortles ice cores we can see precisely how environmental changes taking place at the regional level climate interact with those at the global level". Among information stored in the ice that the researchers identified are signals of radioactive atmospheric deposition resulting from the accident occurred at the Fukushima nuclear plant in Japan in March 2011, only months before the Ortles drilling operations.

"The movement of ice at this depth could be caused by water seepage of surface melting, starting from the rocky margins upstream of the drilling site, and by the fact that now this water, during exceptionally hot summers, is lubricating the bottom part of the glacier and thus allowing the movement", continues Gabrielli.

The research results indicate that the Ortler glacier, as we know it today, was formed about 7,000 years ago, at the end of the so-called 'Climatic Optimum' of the northern hemisphere, a particularly warm period which saw the glaciers retreat up to high altitudes. Subsequently, the beginning of a cooler period, known as Neo-glacial, helped to accumulate snow and ice on the frozen ground again near the top of Ortles. During this new climate period the mummy of the Similaun Man was buried and remained in the ice until the late summer of 1991 when it emerged near the Giogo di Tisa, at 3,210 meters of altitude.

Researchers are analyzing the ice cores identifying stable isotopes of oxygen, the major ions, carbon particles, pollen, trace elements and dust. These parameters can provide important information about climatic conditions from 7,000 years ago.

"One of the extracted cores could enter the Ice Memory project, the new international programme that aims to transport ice cores extracted from low latitudes in an international archive located in Antarctica, where they will be preserved for future generations of scientists", concludes Barbante.

The cores were extracted from an international team of glaciologists led by the University of Ohio, with logistical support from the Autonomous Province of Bolzano and direct participation of researchers from Ca’ Foscari and IDPA-CNR. The international research group is also made up of: U.S. Geological Survey, University of Padova, Udine and Pavia, Enea, Waterstones Geomonitoring; Central Institute for Meteorology and Geodynamics ZAMG and Innsbruck University in Austria; Laboratoire de Géophysique glaciologie et de l'Environnement (LGGE), CNRS and Grenoble Alpes University in France; Paul Scherrer Institute and the University of Bern in Switzerland and the Russian Academy of Sciences. The research was funded by the US National Science Foundation and the Autonomous Province of Bolzano.