There’s an urgent need for more studies of European permafrost, says the leader of a TerraDat team which has just completed a new geophysical survey in the high mountains of Spain.
Professor Christian Hauck’s team repeated readings in the Sierra Nevada mountains 20 years after the company was an intrinsic part of a pan-European study into permafrost in high mountain areas.
Permafrost is permanently-frozen rocks, sand, gravel, and soil, with much of it originating from the last Ice Age.
Recently back from the field trip and analysing the results, Prof. Hauck says some of the new readings showed evidence of the thawing of the permafrost, but that others were inconclusive because of differences in the data and advances in technology since the original study, the PACE (Permafrost And Climate in Europe) Project.
You can read about TerraDat’s involvement with the PACE Project and how permafrost is a key indicator of climate change in our previous blog.
Prof. Hauck stressed that new funding for the study of Europe’s key permafrost sites is vital.
There are currently no good international databases to help the monitoring of permafrost and no European institutional funding for ongoing permafrost monitoring is available.
What did TerraDat survey in 2019?
The 2019 surveys in Sierra Nevada aimed to repeat the ERT (electrical resistivity tomography) profiles conducted in September 1999 within the PACE project.
After 20 years had elapsed, the team wanted to see to what extent climate warming has affected mountain permafrost conditions in Europe.
These surveys are part of a larger initiative which covers many of the old PACE field sites. The Italian and Swiss PACE site surveys were repeated in 2018, and the Norwegian and Spanish sites have been repeated in 2019.
The sites in Svalbard and Sweden are yet to be resurveyed.
Geophysicists from TerraDat took measurements on the Corral del Veleta rock glacier and the mountain saddle, the Lomos de los Machos ridge, both of which had been measured in 1999.
The team also took a cross profile over the same rock glacier feature.
Prof Hauck said: “Comparing the results with the old data from 1999, we found that either we measured in 1999 along a slightly different profile or the data from 1999 suffered partly from insufficient current flow in the coarse blocky surface layer – as the results from 1999 and 2019 differ too much, which is difficult to explain with warming effects only.
“The quality of the 2019 data was good, though.
“In addition to the difficulties in finding the exact profile location from 1999, technology improved since that time and the measurement geometry (more electrodes, longer survey lines) was adapted to match the present state-of-the art.
“This increased the quality of the data, but care has to be taken when comparing the 1999 and 2019 results, as changes may also be due to the different measurement geometries.”
What do the 2019 study’s images tell geophysicists?
The images the team created from their data in 2019 shows a much clearer picture of the extent of the presumed permafrost, thanks to longer and deeper profiles.
Prof Hauck said: “The image of Corral del Veleta shows that the ground ice within the rock glacier quite probably did not change much.
“Maybe the active layer increased slightly. That is not evident in the 2019 results because of the resolution of the image but it can be verified with the digital terrain model available from our Spanish colleagues.
“During our study, it became clear that the rock glacier is a very singular feature in an otherwise unfrozen environment and is very probably of glacial origin.
“However at Lomos de los Machos, the obtained resistivities decreased substantially, or at least smaller resistivities were found than in 1999.
“If this result is confirmed, then it would indicate a thawing of the ground. The resistivities obtained in 2019 are quite low for frozen sediments (which are on top of the bedrock), but 10’000 Ohm is still possible for a warm but frozen environment.”
What are the next steps to build on the work of the PACE Project?
The PACE Project was the beginning of organised, quantitative, and long-term permafrost monitoring and modelling in mountain regions in Europe.
The PACE scientific community is now established and very active, with many national networks in place.
Prof. Hauck said that several steps now need to be taken to ensure effective monitoring of the permafrost.
“A good, coupled monitoring-modelling approach is still missing, no good international data bases for permafrost data exist yet, and no institutional European funding for permafrost monitoring is available,” he said.
All of these issues must now be addressed to ensure we have the best data available for people living in high mountain areas and engineers planning buildings and infrastructure projects.
Degrading permafrost makes buildings, roads, and ski resorts more vulnerable to landslides.
TerraDat Director and Founder Nick Russill added: “Having good international permafrost databases will help teams all over Europe, and the rest of the world, access the data they need to monitor what’s happening with the climate, assess whether the permafrost is melting because of it, how quickly it is melting, and what the impacts might be on nearby settlements.”
– TerraDat, an industrial partner on the original PACE Project, offers the electrical resistivity techniques it used in the Sierra Nevada as a commercial service. A geophysical survey will help warn engineers, planners, and local authorities about any potential for permafrost thaw and ground movement. Call us on +44 (0) 2920 700127 for more information.