The loss of ‘eternal ice’ threatens Mongolian reindeer herders’ way of life

Patches of long-frozen snowpack and ice in the Mongolian steppes are rapidly vanishing — with dire consequences for the reindeer and herders who rely on the icy spots.

About 30 families, members of the Tsaatan people (SN: 1/14/03), live within a remote part of northern Mongolia called the Ulaan Taiga Special Protected Area. Interviews with some of these families have let researchers create a never-before-recorded history of this frozen resource, and gain new insight into how quickly it is vanishing.

During the summer, the Tsaatan bring their reindeer herds to a treeless, tundra valley region called Mengebulag. There, numerous large patches of snow and ice have historically persisted, regardless of season, for decades, perhaps longer. The people call these patches “eternal ice,” or munkh mus.

The ice is an important source of freshwater for families, and reindeer lie on it to cool themselves and seek respite from biting insects, says William Taylor, an archaeologist at University of Colorado Boulder and the Max Planck Institute for the Science of Human History in Jena, Germany. Without the cooling and insect-suppressing ice, the herders told researchers, the animals are more vulnerable to parasite-borne illnesses, and are also increasingly heat-stressed, which reduces their immunity to disease (SN: 12/23/16).

“These folks are immediately experiencing the consequences, because of the way their livelihood is tied to the animals, and tied to the water,” Taylor says. He and his colleagues recount these people’s ethnographic history, increasingly recognized as an important part of documenting ongoing climate change, in a study published online November 20 in PLOS ONE.

Mongolia is one of the driest countries in the world, but “mountains provide these unique microenvironments, where the seasonal precipitation is banked up in the form of snowpack,” Taylor says. That has allowed people to live and herd animals throughout the country.

But many of the ice patches appeared to be shrinking, or even vanishing, Taylor and his colleagues have noted on repeat visits to the region. To learn more about where and when the ice began to vanish, the researchers interviewed, in Mongolian, members of three families with summer camps in the region and who have visited the ice patches year after year. Loss of eternal ice patches appears to have accelerated in the last decade, the families reported; many long-standing patches melted away completely during the summers of 2016, 2017 and 2018.  

“The really troubling stories were the ones where the families took us to where patches used to be, and now they are just barren rock faces,” Taylor says. “The term munkh mus —it’s a term of respect,” he adds. “They don’t use ‘eternal’ lightly in the Mongolian language. And the loss is, in many ways, felt as a tragic one.”

The study doesn’t analyze how the loss of these ice patches is related to warming temperatures in the region. But the team notes that average temperatures in Mongolia as of 2001 were already 1.5 degrees Celsius higher than the 20th century average, according to a United Nations climate change report.

Using locations given by the families as well as satellite data from 2016 and 2017, the researchers did visit 11 existing ice patches and two sites that were covered in ice in 2016 but are now completely melted. Those surveys, by horseback, yielded wooden artifacts, once buried by the ice, that Taylor says represent clues to the history of reindeer herding in the region. For instance, a long, cylindrical wooden stick may have been a “scaring stick,” an object herders still use to control the behavior of wild reindeer, the herders told researchers. Lines of such sticks, placed upright in the snow, can trigger the animals’ instincts to shy away from a location.

Carbon-14 dating suggests these artifacts were used in the 1960s or 1970s, the team found. Melting ice patches may have previously exposed many other, perhaps older, organic artifacts, once preserved in ice that have already degraded away. “After those are gone, it’s impossible to backtrack and extrapolate what may have been lost,” Taylor says.

Since the early 2000s, similar finds have begun emerging from melting ice in Norway, North America and in the Alps, says Lars Holger Pilø, a glacial archaeologist with the Glacier Archaeology Program in Oppland, Norway. Now, scientists are racing to collect oral histories and vulnerable artifacts at rapidly melting sites in remote areas. “Many of the finds are in organic materials that are not preserved elsewhere, but which have survived hundreds or thousands of years inside the ice like in a time machine,” Pilø says.

Taylor’s group is the first to undertake such glacial archaeology work in Mongolia, Pilø says. “They are doing really important work.” The ethnographic information “adds meat to the bone, so to speak. It makes it easier to understand why finds are made in ice patches and glaciers and how the finds should be interpreted.”