13.3.2026
An international research team, including Heidelberg University researchers Prof. Dr. Werner Aeschbach and Dr. David Wachs from the Institute of Environmental Physics and Prof. Dr. Markus Oberthaler from the Kirchhoff Institute for Physics, has uncovered a unique record of climate and environmental history in a glacier in the Ötztal Alps. However, this archive is now under serious threat. Scientists warn that rapidly melting Alpine glaciers could destroy important records of Earth’s environmental history before they can be fully studied.
At the center of the study is the Weißseespitze glacier, located on the border between Austria and Italy. A nearly ten-meter-long ice core drilled down to the glacier bedrock contains a record of atmospheric changes spanning almost two thousand years. By analyzing trace elements, microcharcoal, and chemical compounds formed during wood burning, researchers were able to reconstruct how air pollution, wildfire activity, and volcanic events have changed over the centuries.
Ice cores from high-mountain glaciers function as natural archives of the atmosphere. Year after year, snowfall deposits particles from the air, which are subsequently preserved in the ice. Using modern isotope and elemental analyses, researchers can reconstruct environmental conditions from past centuries.
“These remarkable climate archives function much like a history book: past atmospheric conditions and environmental changes are recorded in their layers,” said Dr Azzurra Spagnesi of the University Ca’ Foscari of Venice, lead author of the article in Frontiers in Earth Science. “Alpine glaciers offer a unique opportunity to investigate the critical transition between pre-industrial and industrial times, because of their proximity to human settlements.”
The analyzed ice layers date from around 349 BCE to the 17th century. Particularly striking is a period of elevated metal concentrations between 950 and 1280 CE, which coincides with intensified medieval mining and smelting activities in the Alpine region. At the same time, the researchers identified increased levels of microcharcoal, indicating more frequent and intense fires, possibly promoted by a prolonged drought period between about 950 and 1040 CE.
In addition to human activities, volcanic eruptions, dust transport, and climatic fluctuations also left clear chemical signatures in the ice.
However, these valuable natural archives are under immediate threat. When the research team revisited the drilling site seven years later, they found that the glacier had shrunk significantly: instead of roughly 9.5 meters of ice thickness, only about 5.5 meters remained in 2025.
Researchers therefore warn that a race against time has begun. If Alpine glaciers continue to melt, unique records of past climate variability could be lost forever.
“If glaciers disappear, we also lose the chemical and physical information they contain about past climate conditions,” the researchers emphasize. “Protecting glaciers therefore also means safeguarding the memory of Earth’s climate.”
Photo credit: Norbert Span
