This story was first published on The Conversation. It is now available here under a Creative Commons licence.
Ice is essential for life in the high mountains of the world. Glaciers and other accumulations snow and ice can be found all year, from the Rockies to Himalayas. These ice patches, which are often found on slopes shaded from the sun, transform barren peaks into biological hotspots.
These snow and ice patches are important to me as an archaeologist because they provide a rare glimpse into the past through the fog of alpine history. Ice patches can be used as natural deep-freezers when objects are lost in the ice. They can hold snapshots of culture, daily life, technology and behavior for thousands of years.
In every hemisphere, frozen heritage is melting out of mountain ice. As this happens, small groups archaeologists scramble to raise the funds and staffing to study and identify these objects before they disappear.
I am working with a team of researchers from the University of Colorado and the National Museum of Mongolia and other partners around the globe to identify, analyze and preserve ancient materials that have emerged from the ice in Mongolia's grassy steppes. These discoveries are a huge help for scientists understanding the past.
To escape heat and insects, domestic reindeer in northern Mongolia use an ice sheet to cool off. Others try the same thing in an area where recent melting has left no perennial ice, which can harm herd health. 2019 Taylor et al, CC BY
Unique plants flourish in the well-watered margins and ice patches during the summer months. Large animals like bison, caribou, elk and sheep seek the ice for cooling off from or escape from insects.
Ice patches provide water and plants for nearby residents. The Mongolian dry steppes are fed by meltwater from the mountain ice. Domestic reindeer search for the ice the same way they do wild animals. Climate warming aside, the ice margins serve as magnets for people and repositories for the materials they leave behind.
Ice patches are important tools for understanding the past because of their cultural and biological significance. Soft, organic materials were used to create tangible objects that were used by early hunters and herders in mountainous areas. These fragile objects are prone to weather and erosion. Items that are otherwise susceptible to decay can be kept for many centuries in deep freeze conditions, even if they are thrown away or lost in the snow.
An 1,500-year-old heap of argali sheep skulls & horn curls melts from a glacier margin, western Mongolia. William Taylor, CC BY -ND
High mountains are subject to extreme weather conditions and are therefore often far away from urban centers, where modern researchers are concentrated. These factors make it difficult to record significant contributions from mountain people to the human story.
In Mongolia, for example, the Altai high mountains housed the oldest pastoral societies. These cultures are only known through a handful of burials, and the ruins a few windswept stones buildings.
One of our discoveries was a finely weaved piece of animal hair rope, which we found in a melting mountaintop glacier in western Mongolia. It was found among the rocks at the edge the retreating ice when we went to survey it. It could have been a bridle, or harness. We spotted it among the rocks at the edge of the retreating ice. Scientific radiocarbon dating proved that the artifact was actually older than 1,500 years.
These objects provide rare clues to the daily lives of the ancient Mongolian herders. We can perform advanced analysis back in the laboratory to reconstruct the choices and materials of early herding cultures, which eventually led to the creation of pan-Eurasian empires such as the Xiongnu or the Great Mongol Empire.
Scanning electron microscopy, for example, allowed us to determine that camel hair was used as a fiber in this rope bridle. Collagen preserved in ancient sinew also revealed that deer tissue was used by the Bronze Age to attach an arrowhead to its shaft.
An arrow preserved in ice patches of western Mongolia from the Bronze Age period pasta was found with sinew lashing, red pigmentation and other details that revealed previously unknown information about the region's early inhabitants. Peter Bittner. CC BY -ND
Sometimes the objects that are found end up challenging archaeologists' basic assumptions about the past. My colleagues and I discovered that the ice and Mongolian glaciers in this region contained hunting artifacts. These included spears and bows as well as bones from big game animals such argali sheep. This was over a period of three millennia. These findings show that mountain ice hunting has been an integral part of Altai Mountains pastoral subsistence and culture for thousands of years.
The clock is ticking. As scorching summer temperatures wreak havoc on the Pacific Northwest rainforest and wildfires devastate the Siberian Arctic, the summer of 2021 looks set to be one the hottest. Extremely cold regions are most affected by rising temperatures.
Satellite photos of western Mongolia show that over 40% of the ice-covered surface has disappeared in the region my colleagues and me study. Each artifact may only have a short window of recovery time after it has been exposed to melting ice.
Satellite photos show how glacier and ice have melted in the western Mongolian study area over a period of less than 30 years. Taylor, W., Hart, I., Pan, C. et al. High altitude hunting, climate changes, and pastoral resilience in eastern Eurasia. Sci Rep 11, 14287 (2021), CC BY
It is difficult to estimate how much material is being lost due to the magnitude of climate change. Many high mountains in Central and South Asia have not been systematically surveyed for melting artifacts. Many international projects have been stopped since the COVID-19 pandemic, which has also led to reductions in pay and complete closure of archaeology departments at top universities.
The irreplaceable scientific data of ice patches is invaluable to researchers who can help them understand the effects of climate change on our world today and characterize ancient climate responses.
The ice patches not only preserve human-made artifacts, but also ecofactsnatural materials that track important ecological changes such as shifting tree lines and changing animal habitats. Scientists can use these data sets and artifacts to gain insight into the adaptations of people to major ecological changes. This could help them prepare for the 21st century climate crisis.
The ice-covered ice area that was once permanent (left) is now gone. This was the first time the ice has ever melted in local history. 2019 Taylor et al, CC BY
The dwindling ice sheets are also threatening the health of all living things, including animals, plants, and humans. My research in northern Mongolia shows that summer ice is threatening the health of domestic reindeer. Local herders are concerned about the effect of ice loss on pasture viability. The melting ice can also be influenced by other environmental changes. In western Mongolia, poaching and poorly controlled tourism hunting have led to a dramatic decline in animal population.
The ice loss is also reducing humanity's resilience over the coming years, as a result of the rising heat.
William Taylor is an assistant professor at the University of Colorado Boulder and curator of archaeology.
