How thick is the old ground ice?

AWI researcher Jens Strauss and his IPA Action Group are working on the world’s first map of the Yedoma region.

To avoid unnecessary confusion, this story begins with a clarification of terms – because not all types of permafrost are the same. There are essential differences: “Permafrost refers to soil that has been frozen for at least two years,” explains researcher Jens Strauss from the AWI Potsdam. “But our specific focus is on the Yedoma permafrost – permanently frozen soil that formed during the last ice age and is permeated by long ice wedges.”

These up to 50-metre-long deposits of sediment and ground ice are the focus of a new two-year data synthesis project launched by the International Permafrost Association, which Jens Strauss is coordinating. Working together with his colleagues at the AWI and researchers from Russia, the USA, Canada and Sweden, his goal is to determine the distribution and regional thickness of the Yedoma, and to depict these aspects in the first-ever Arctic-wide Yedoma map.

Yedoma - A special permafrost form

“There are different schools of thought in international Yedoma research, and with this project we want to get them all together at the same table and effectively combine their data. After all, this special form of permafrost is especially important when it comes to determining how great the potential levels of greenhouse gas slumbering in the permafrost regions are,” says Strauss.

In addition to ice wedges, Yedoma permafrost contains a great deal of organic material, which is then broken down by microorganisms when it thaws. However, this massive carbon reservoir is largely ignored in today’s climate models. As the researcher relates, “All of our current estimates on potential sources of greenhouse gases involve considerable uncertainty, partly because we still don’t know how thick the Yedoma is in different parts of the Arctic. The map we’re making is designed to fill that gap.”

Pool of measurement data

In addition to measurement data from drilling sites in the Yedoma region, the new map will incorporate remote sensing data, geological maps and datasets from Russia that were never before digitalised. “Russian researchers have been working on this topic for over 50 years, but many of their results are only available in Russian. We will translate and digitalise those datasets, making them accessible for the international research community,” says Strauss.

The map will ultimately be released as a GIS variant and as a scientific dataset, as well as a web version for Wikipedia, ensuring that non-experts can also learn more about the significance of Yedoma. (Sina Löschke)

Ice wedges come to day light at eroded cliffs.
Ice wedges come to daylight at eroded cliffs. (Photo: Thomas Opel, Alfred-Wegener-Institut)
Ice wedges (Yedoma) on the Bol'shoy Lyakhovsky, the most southern Island of the New Siberian Archipelago
Ice wedges on the New Siberian Island Bol'shoy Lyakhovsky (Photo: Georg Schwamborn)