Miriam Jackson explaining to students the importance of permafrost. (Photo: Chimi Seldon/ICIMOD)

“Do you know that the ground can be frozen?”, asks Miriam Jackson, our Senior Cryosphere Expert, to a group of bewildered students of MahaBouddha Secondary School in Yalbang, Humla District, Nepal.

We were on the final leg of our fieldwork in Humla, where we had just installed micro weather stations and deployed ground temperature sensors in various sites of the Limi Valley. Along with conducting important scientific work, educating communities about the scientific processes and implications of climate change are also critical parts of our work on permafrost. In Yalbang, we interacted with students from grades 9 and 10 to teach them about permafrost. This was the first time most of them had heard that the ground can be frozen.

Permafrost is the soil, rock, or sediment, usually held together by ice, that stays frozen for at least two consecutive years. It can be found in high-latitude and high-elevation regions, mostly 4,000 metres above the sea level in the High Mountains in case of the HKH region. A significant part of Humla falls within the famous Limi Valley, and as we travelled through the valley, our experts identified several signs that showed the presence of permafrost.

One of these signs is the rock glaciers, which are frequently used as a proxy to map permafrost distribution. Rock glaciers in the Hindu Kush Himalaya are hydrologically significant because they hold large amounts of water that are frozen. Further, rock glaciers are more resistant to climate change than glaciers. Our colleague, Prashant Baral, explains how to differentiate active rock glaciers from inactive ones.

ICIMOD has been piloting permafrost research to better understand the impacts of permafrost thaw in Humla and its possible effects on steep slopes. In the form of ice, permafrost helps bind soil and other loose material within the ground in high mountains. However, as the climate warms, permafrost starts to thaw in many parts of the world. Melting permafrost can lead to more frequent and greater landslides, especially on steep slopes.

Permafrost thaws have direct implications on the livelihoods, particularly mountain communities. It is therefore imperative to include a social angle in the physical permafrost research to collectively improve disaster preparedness, raise awareness about permafrost occurrence, and build adaptative capacity where needed.

As part of the pilot study, our research team installed an automatic weather station in Tungling, which records soil moisture, solar radiation, and ground and air temperatures in the area. Data from the weather station will help the scientific community understand the changes in ground thermal regime and subsequent changes in permafrost landscapes. Understanding these changes is essential in making recommendations on safe locations to build and develop infrastructure.

A TidbiT sensor is commonly used to record ground temperature in permafrost research. Data collected with TidbiT loggers helps determine the mean annual ground surface temperature and enables scientists to better understand and distinguish permafrost and non-permafrost areas. During the fieldwork, our team deployed 10 GST sensors (TidbiT) loggers at selected sites in Limi Valley and retrieved data from the five TidbiT sensors deployed in September 2021.

The impacts of permafrost thaw are likely to be significant and far-reaching. It is therefore essential to understand and address these impacts as part of the efforts to address climate change. Despite widespread permafrost occurrence in the HKH, this major element of the cryosphere is under researched in the region. ICIMOD, through the pilot research in Humla, Lower Mustang, and Langtang will continue working to promote permafrost research in the region and the potential impacts of permafrost thaw to develop effective adaptation strategies.

Chimi Seldon

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