(2ND EXPLAINER STORY) How climate change is threatening permafrost’s delicate balance

Permafrost is the hidden frozen “glue” – a layer formed by ice, rock and soil – that holds icy northern landscapes together. From the Alps to the Arctic, permafrost is slowly warming, a process that could accelerate global climate change. Here’s what you need to know about permafrost research in Switzerland and beyond.

What is permafrost?

Permafrost is rock, scree or moraine, mixed with ice, which remains at or below 0° Celsius (32° Fahrenheit). Around 11% of the Earth’s land mass is covered by permafrost. It is found in all polar and high mountain regions of the world and is most abundant in the northern hemisphere, in the Arctic and high Arctic regions of Canada and Russia.

PERMOS

Permafrost is also found in the Alps. It covers some 3-5% of Switzerland’s territory and is found in scree slopes and rock walls at altitudes above 2,600 metres. It is mostly invisible because it lies beneath the surface of mountains. Permafrost’s temperature is an important climate indicator. It also influences how the landscape evolves, the construction of mountain infrastructure and slope stability.

SHORT 1m ANIMATION –PERMAFROST ANIMATION TO TRANSLATE FROM GERMAN IN TITLETOOL

In permafrost regions, the uppermost layer of the ground thaws during warmer weather and is called the “active layer”. Below that is the permafrost body.

The thickness of the lower layer in the Swiss Alps ranges from tens of metres to several hundreds of metres below the highest peaks. In the coldest polar regions, the depth of permafrost can extend as far as 1.7 km.

SWI swissinfo.ch

What’s the state of permafrost thawing in Switzerland and the rest of the world?

An international studyExternal link led by Swiss scientist Jeannette Nötzli published last December in the journal Nature revealed how permafrost temperatures in Europe’s mountain regions are rising, stronger and faster than ever.

Researchers collected and analysed measurements in nine European countries, from Svalbard near the Arctic Circle to the Alps and the Sierra Nevada mountains in southern Spain. Their results clearly showed that mountain permafrost is getting warmer throughout Europe. In the past ten years, the temperature at a depth of ten metres has increased by over 1°C in some places.

“The warming of permafrost in the mountains is significant,” said Nötzli, who is a researcher at the WSL Institute for Snow and Avalanche Research (SLF) in Davos. “And it is observed in all regions, depths and time periods that we have looked at.”

The study published in NatureExternal link, showed that the increase in permafrost temperatures in Europe’s mountainous regions are similar to that in the Arctic. The greatest warming was measured at the highest-altitude and northernmost locations. Scientists also found that when temperatures in the ice-rich permafrost approach 0°C, the warming slows significantly and almost stops because energy is needed to melt it underground. But once the ice in the permafrost has melted, temperatures rise again.

The general thawing trend looks set to continue, the researchers say. “This can also be seen from the fact that the warming at a depth of ten metres is greater than deeper underground,” said Nötzli. The scientists warn that the observed warming will continue to penetrate to greater depths in the coming decades.

The permafrost warming trendExternal link is visible across the Swiss Alps. Over the past 20 years, the Permafrost Monitoring Network PERMOS has kept watch at 30 sites. Its measurements paint a worrying picture: permafrost temperatures have reached record levels in many high-altitude locations, as have the thickness of the active layer and the velocity of rock glaciers. In Switzerland there is “no respite for permafrost”,External link PERMOS reported last June.

Edited by Veronica De Vore